Re: [Tutor] Looping through Dictionaries
On 05/23/2017 11:38 AM, Rafael Knuth wrote:
> I wrote a function (shopping list) which calculates the total price of
> the purchase (quantity * price) as well as the stock change (stock -
> quantity). I know the latter is imperfect (my function does not take
> into account if items are out of stock for example, but that's my next
> challenge. The function does exactly what it's supposed to do:
>
> def shopping(quantity, price, stock):
> total = 0
> for key in quantity:
> total += quantity[key] * price[key]
> stock_update = stock[key] - quantity[key]
> print(stock_update)
> print(total)
>
> quantity = {
> "bapple": 10,
> "banana": 20
> }
>
> price = {
> "bapple": 5,
> "banana": 3
> }
>
> stock = {
> "bapple": 20,
> "banana": 50
> }
>
> shopping(quantity, price, stock)
>
> Now, I want to print the item next to the stock update, and I am
> receiving an error message. I couldn't figure out how to fix that:
in the code below you're trying to use "value" as your key, but it isn't
the key. Why did you change that from the code above?
it helps if you include the errors, by the way :)
>
> def shopping(quantity, price, stock):
> total = 0
> for key, value in quantity.items():
> total += quantity[value] * price[value]
> stock_update = stock[value] - quantity[value]
> print(key, stock_update)
> print(total)
>
> quantity = {
> "bapple": 10,
> "banana": 20
> }
>
> price = {
> "bapple": 5,
> "banana": 3
> }
>
> stock = {
> "bapple": 20,
> "banana": 30
> }
>
> shopping(quantity, price, stock)
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Re: [Tutor] Looping through Dictionaries
On 23/05/17 18:38, Rafael Knuth wrote:
> Now, I want to print the item next to the stock update, and I am
> receiving an error message. I couldn't figure out how to fix that:
So show us the error message, all of it.
I can't begin to guess what it might be.
UI also don't understand what "print the
item next to the stock update" means.
Do you mean the actual location of the
data in the printed string? Or do you
mean the value(which?) next to the one
in your function?
Can you show us some examples?
> def shopping(quantity, price, stock):
> total = 0
> for key, value in quantity.items():
> total += quantity[value] * price[value]
> stock_update = stock[value] - quantity[value]
I don't see how this would work. value is the value
from the dictionary which is an integer. But you are
using it as a key which should be a string?
So in your first iteration key,value will be
key = 'bapple', value=10
so you are trying to evaluate
stock[10]-quantity[10]
but thee are no such items.
I suspect you mean:
stock['bapple'] - quantity['bapple']
or in your function:
stock[key] - quantity[key]
But in that case you don;t need the value from items()
you can just iterate over the keys:
for item in quantity:
...
stock_update = stock[item] - quantity[item]
print(item, stock_update)
> print(key, stock_update)
> print(total)
>
> quantity = {
> "bapple": 10,
> "banana": 20
> }
>
> price = {
> "bapple": 5,
> "banana": 3
> }
>
> stock = {
> "bapple": 20,
> "banana": 30
> }
>
> shopping(quantity, price, stock)
I'm not clear on what these variables indicate.
What is the difference between quantity and stock?
Also this might be a good time to look at classes
and objects. You could avoid all the multiple
stores by putting the various data elements
in a class. This would avoid the potential
headaches caused by mis-typing the item names
in each store, for example. You could then
have variables bapple and banana and access,
for example, bapple.quantity and bapple.price.
And just keep a simple list of items.
Just a thought...
--
Alan G
Author of the Learn to Program web site
http://www.alan-g.me.uk/
http://www.amazon.com/author/alan_gauld
Follow my photo-blog on Flickr at:
http://www.flickr.com/photos/alangauldphotos
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Re: [Tutor] looping - beginner question
On Thu, Mar 2, 2017 at 8:42 AM, Rafael Knuth wrote:
> I wrote a program that is supposed to take orders from customers in a bar.
> If the desired drink is available, the customer will be served. If
> not, he will be informed that the drink is not available. This is what
> I wrote:
>
> bar = ["beer", "coke", "wine"]
>
> customer_order = input("What would you like to drink, dear guest? ")
>
> for drink in bar:
> if customer_order != drink:
> print ("Sorry, we don't serve %s." % customer_order)
> else:
> print ("Sure, your %s will be served in a minute!" %
> customer_order)
>
> What I want the program to do is to "silently" loop through the list
> of drinks and to print the correct answer. Instead, it loops through
> each item on the list like this:
>
> >>>
> == RESTART: C:/Users/Rafael/Documents/01 - BIZ/Python/Python Code/PPC_4.py
> ==
> What would you like to drink, dear guest? coke
> Sorry, we don't serve coke.
> Sure, your coke will be served in a minute!
> Sorry, we don't serve coke.
> >>>
>
> Rafael, don't forget that your input string might have a newline character
that needs to be cleaned off. I think, can't test at the moment. The
simplest test might be:
if drink in bar:
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Re: [Tutor] looping - beginner question
On 03/02/2017 08:06 AM, Alan Gauld via Tutor wrote:
> On 02/03/17 13:42, Rafael Knuth wrote:
>
>> bar = ["beer", "coke", "wine"]
>>
>> customer_order = input("What would you like to drink, dear guest? ")
>>
>> for drink in bar:
>> if customer_order != drink:
>> print ("Sorry, we don't serve %s." % customer_order)
>> else:
>> print ("Sure, your %s will be served in a minute!" % customer_order)
>>
>> What I want the program to do is to "silently" loop through the list
>
> So you only want the sorry... message if the loop completes without
> finding a drink. That means you need to put that print statement after
> the loop. Python includes a feature for that - a for/else construct.
>
> for drink in bar:
> if drink == customer_order:
>print(Sure...)
>break #exit loop and avoid else
> else:
> # only if the loop completes normally
>
> However, there is another way to do this that doesn't
> use an explicit loop: the 'in' operator
>
> if customer_order in bar:
> print("sure)
> else:
> print ("Sorry)
To follow on to what Alan said, you don't need to loop over a list (or
tuple, or dictionary, or other "iterable") to find out if it contains an
item. You can just test membership directly.
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Re: [Tutor] looping - beginner question
On 02/03/17 13:42, Rafael Knuth wrote:
> bar = ["beer", "coke", "wine"]
>
> customer_order = input("What would you like to drink, dear guest? ")
>
> for drink in bar:
> if customer_order != drink:
> print ("Sorry, we don't serve %s." % customer_order)
> else:
> print ("Sure, your %s will be served in a minute!" % customer_order)
>
> What I want the program to do is to "silently" loop through the list
So you only want the sorry... message if the loop completes without
finding a drink. That means you need to put that print statement after
the loop. Python includes a feature for that - a for/else construct.
for drink in bar:
if drink == customer_order:
print(Sure...)
break #exit loop and avoid else
else:
# only if the loop completes normally
However, there is another way to do this that doesn't
use an explicit loop: the 'in' operator
if customer_order in bar:
print("sure)
else:
print ("Sorry)
hth
--
Alan G
Author of the Learn to Program web site
http://www.alan-g.me.uk/
http://www.amazon.com/author/alan_gauld
Follow my photo-blog on Flickr at:
http://www.flickr.com/photos/alangauldphotos
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Re: [Tutor] looping generator
On 07/01/16 18:31, richard kappler wrote: > Alan, have you ever actually been guilty of 'missing something'? :-) Actually quite often. Usually when its late at night(tired) or early morning(no coffee) or I'm rushing to go someplace. But it happens quite a lot, Usually Steven or Peter or someone will jump in and show me the error of my ways. ;-) -- Alan G Author of the Learn to Program web site http://www.alan-g.me.uk/ http://www.amazon.com/author/alan_gauld Follow my photo-blog on Flickr at: http://www.flickr.com/photos/alangauldphotos ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] looping generator
Hi there Richard,
>I have a stream of incoming xml data. I can receive the data, parse
>the data, etc, so long as I don't get fancy and I have a miniscule
>delay in between each message. If I get rid of the time delay,
>which I need to, I need the script to continuously process the
>incoming messages. Here's what I have:
To begin, I have a suggestion that is not specifically a Python
suggestion. I have read several of your prior emails describing
your problem.
If I were faced with the problem of receiving and processing data
from remote "dumb" nodes, I would separate the software components
into, at least, two distinct pieces.
1. Trust the filesystem. Write one software component that
receives the data from the wire and writes it out to a
configurable directory. If, for whatever reason, you lose the
data, the performance of the rest of the system does not
matter. Thus, capturing the data is the most important first
step. Use your system's daemonization tools to run this
service.
2. Improve performance of the parsing and processing tools.
Teach the tools how to read the data stored in the filesystem
and iteratively locate hot spots, performance issues, parsing
problems or data shortcomings.
Here are a few disorganized thoughts about why and how to do it this
way:
* the network listener becomes much simpler since it will not
parse, and will only write out to disk
* let's assume each XML chunk is about 128k and you have 30 data
sources and are receiving 4 chunks per second from each; total
data volume is 1.5MiB, easily able to be received and written to
disk on modern hardware
* you could segregate the XML chunks also by data source (and
maybe also time), writing out each chunk into the filesytem; if
you break each message into its own file, that would be a large
number of files (with attendant open() and close() costs), so
perhaps writing out a new file every minute or fifteen minutes;
here's a possible file naming scheme
received/2016/01/-10.143.17.227.data
received/2016/01/0100-10.143.17.227.data
received/2016/01/0200-10.143.17.227.data
...
received/2016/01/2300-10.143.17.227.data
that would leave you with about 720 files per daily directory,
something that is eminently manageable for modern filesystems
(and for any pesky humans who happen to be wandering around)
* if you write out the stream of data to the filesystem, your
network listener need only locate the \x02 byte and the \x03
byte--it could ensure that every file it wrote contained a first
byte of \x02 and a final byte of \x03
* you can independently upgrade the parsing and processing tools
and the data recording service
* if you retain these files, you can "replay" the past (errors,
bursts, reprocessing); alternatively simply delete the files
after they are processed for downstream consumers
* separating the responsibilities of each software component also
simplifies your diagnosis and software authorship process; first
you can make sure that you are recording the data properly; once
that is done, you can start to process your data, moving along
to performance questions next
Now, below, I have a few Python-specific points or questions:
>#!/usr/bin/env python
>
>import socket
>import lxml.etree as ET
>
>def dataRecv(connection):
>print 'receiving'
>while True:
>data = connection.recv(65536)
>while True:
>print "writing to data.in"
>f2.write(data)
>start = data.find('\x02')
>end = data.find('\x03')
>message = data[start+1:end]
>print "writing to messages.out"
>f3.write(message)
>yield message
You do not define f2 and f3 until below. If you are going to do
this, pass them into the function f2 and f3. I.e.
def dataRecv(connection, f2, f3):
while True:
# wait for a connection
connection, client_address = sock.accept()
q = dataRecv(connection, f2, f3)
>def dataParse(message):
>print 'parsing'
>xslt = ET.parse('stack13.xsl')
>dom = ET.XML(message)
>transform = ET.XSLT(xslt)
>newdom = transform(dom)
>f1.write(str(newdom))
>
>
>sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
>sock_addr = ('', 2008)
>#data = sock.makefile('r')
>sock.bind(sock_addr)
>sock.listen(5)
>print 'listening'
>
>f1 = open('parser.out', 'a')
>print "opening parser.out"
>f2 = open('data.in', 'a')
>print "opening data.in"
>f3 = open('messages.out', 'a')
>print "opening messages.out"
>
>while True:
># wait for a connection
>connection, client_address = sock.accept()
>q = dataRecv(connection)
>dataParse(q.next())
>
># close sockrx
>#connection.close()
>
>f1.close()
>
>
By the way, keep on breaking these things into functions
Re: [Tutor] Looping over histogram plots
On 27/06/2012 08:47, Alan Gauld wrote: On 27/06/12 00:32, Elaina Ann Hyde wrote: Thanks for the comment, the set type is no problem for me, this is just a variable that I call set... and it works great for my purposes, It may work just now but if you ever decide you need to use a Python set you will be unable to because you have effectively hidden that data type. And it's unlikely to beimmediately obvious why its not working. That's why its a bad idea to use the built-in type names as variables. eg: myList = [1,2,3,3,4,5,6,3,1,5] myUniqueList = list(set(mylist)) # remove duplicates In your program the second line would fail. If you are confident you will never use sets then its not an issue, but these decisions have a habit of coming back to bite you in the future! And they always seem to bite the most tender part of the anatomy that they can find :) -- Cheers. Mark Lawrence. ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Looping over histogram plots
On Wed, Jun 27, 2012 at 08:47:08AM +0100, Alan Gauld wrote: > On 27/06/12 00:32, Elaina Ann Hyde wrote: > > > Thanks for the comment, the set type is no problem for me, this is > >just a variable that I call set... and it works great for my purposes, > > It may work just now but if you ever decide you need to use a Python set > you will be unable to because you have effectively hidden that data > type. And it's unlikely to beimmediately obvious why its not working. > That's why its a bad idea to use the built-in type names as variables. This is called "shadowing a built-in", and is discouraged for exactly the reasons that Alan mentions. It is much less risky to shadow built-ins inside small functions, so you are not surprised that the built-in doesn't work as expected. When you do it deliberately to change the behaviour of a built-in, it is often called "monkey-patching"[1] which is a risky, sometimes useful but advanced technique. Nevertheless, any of these cases should be used with care, and only if necessary. [1] Sometimes called "raving insanity" *grin* -- Steven ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Looping over histogram plots
On 27/06/12 00:32, Elaina Ann Hyde wrote: Thanks for the comment, the set type is no problem for me, this is just a variable that I call set... and it works great for my purposes, It may work just now but if you ever decide you need to use a Python set you will be unable to because you have effectively hidden that data type. And it's unlikely to beimmediately obvious why its not working. That's why its a bad idea to use the built-in type names as variables. eg: myList = [1,2,3,3,4,5,6,3,1,5] myUniqueList = list(set(mylist)) # remove duplicates In your program the second line would fail. If you are confident you will never use sets then its not an issue, but these decisions have a habit of coming back to bite you in the future! -- Alan G Author of the Learn to Program web site http://www.alan-g.me.uk/ ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Looping over histogram plots
Yay Python:
The solution was a syntax one, if anyone else ever feels like massively
multi-plotting histograms, here is the working code:
#--
fig, axes = plt.subplots(nrows=5, ncols=6, figsize=(12,6))
index=0
for b in axes:
for ax in b:
index=index+1
set=(dat['a'+str(index)] == 1.00)
#write the data
n, bins, patches = ax.hist(VGSR[set], 30, normed=1)
#label the axis
if index==13.0:
ax.set_ylabel('counts')
if index >= 25.0:
ax.set_xlabel('VGSR')
plt.show()
#---
~Elaina Hyde
--
PhD Candidate
Department of Physics and Astronomy
Faculty of Science
Macquarie University
North Ryde, NSW 2109, Australia
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Re: [Tutor] Looping over histogram plots
Dear Don, Thanks for the comment, the set type is no problem for me, this is just a variable that I call set... and it works great for my purposes, I do suspect it is something in the way that matplotlib/pyplot deals with histograms, but I have not so far been able to find the right syntax. Note, the first code example works great, it is only the second (with the hist attempt) that does not do well. It creates 29 blank plots and 1 histogram instead of 30 histograms... so probably it does need a different phrasing, but the one you suggest gives invalid syntax. ~Elaina On Tue, Jun 26, 2012 at 9:19 PM, Don Jennings wrote: > > Message: 1 > > Date: Tue, 26 Jun 2012 18:40:50 +1000 > > From: Elaina Ann Hyde > > To: tutor@python.org > > Subject: [Tutor] Looping over histogram plots > > > > >set=(dat['a'+str(index)] == 1.00) > > You should not override the builtin set() type [1] as you've done here by > assigning it. > > > #write the data > >P.hist(VGSR[set],bins=30, normed=True) > > I am not familiar with matplotlib, etc. but given that the primary > difference in your two code samples is where you write the data, I suspect > you want something like: > >ax.plot(P.hist(VGSR[set],bins=30, normed=True)) > > Take care, > Don > > [1] http://docs.python.org/library/stdtypes.html#set -- PhD Candidate Department of Physics and Astronomy Faculty of Science Macquarie University North Ryde, NSW 2109, Australia ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Looping over histogram plots
> Message: 1 > Date: Tue, 26 Jun 2012 18:40:50 +1000 > From: Elaina Ann Hyde > To: tutor@python.org > Subject: [Tutor] Looping over histogram plots >set=(dat['a'+str(index)] == 1.00) You should not override the builtin set() type [1] as you've done here by assigning it. > #write the data >P.hist(VGSR[set],bins=30, normed=True) I am not familiar with matplotlib, etc. but given that the primary difference in your two code samples is where you write the data, I suspect you want something like: ax.plot(P.hist(VGSR[set],bins=30, normed=True)) Take care, Don [1] http://docs.python.org/library/stdtypes.html#set ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Looping
> > xrange was a kludge to improve on range's memory efficiency > but it is a horrible name that obscures the code. > > Also it does not exist in v3 so if you use it you will need to change > the code for v3. It is as well to be as consistent with v3 as possible > IMHO > > Alan G I have felt this way also (i.e., "xrange was a kludge" and "it is a horrible name"), and have resisted the general adoption of xrange in my code. Fortunately, I rarely use range, but iterate over sequences directly; or if I absolutely need the item's index, I iterate over enumerate(seq). But even if you use "range" exclusively, you may need to change code when migrating to Python 3. In Py2, range returns a list; in Py3 range returns an iterator (a la Py2-xrange's behavior). If you have code that uses the value returned from range as a list, then in Py3 you will need to explicitly convert it to a list using "list(range(n))". I concur with Alan's suggestion that you code to Py3 semantics, but there are certainly cases where xrange makes sense vs. range (such as doing some sort of repetitive test 1e8 times, there is no sense in creating a 100-million entry list just to iterate over it). So I'll propose some usages for those who use range: 1. For Py2-Py3 range-xrange compatibility, add this code to the top of your Python scripts: try: range = xrange except NameError: pass In this way, your code under Py2 will use xrange whenever you call range, and you will adopt the future-compatible range behavior. (Hmm, maybe this would have been a good option to add to the "future" module...) 2. In all cases where you really must use the result returned from range as a list, ALWAYS write this as "list(range(n))", as in: nonnegative_numbers_up_to_but_not_including_10 = list(range(10)) even_numbers_up_to_but_not_including_20 = list(range(0,20,2)) Using the "list(range(n))" form when you actually need a list will prepare you for the change in idiom when you upgrade to Py3, and is fully Py2 compatible (even if you don't first bind xrange to range as in suggestion 1 - it simply copies the original list). It also makes it very explicit that you REALLY WANT THE RANGE AS A LIST, and not just as something for counting up to n. -- Paul ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Looping
"Matt" wrote As an aside, why use range rather than xrange? I was under the impression that xrange is a generator and therefore more memory efficient. xrange was a kludge to improve on range's memory efficiency but it is a horrible name that obscures the code. Also it does not exist in v3 so if you use it you will need to change the code for v3. It is as well to be as consistent with v3 as possible IMHO Alan G ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Looping
On Mon, Apr 20, 2009 at 12:34 PM, Matt > wrote: > Thank you. Func is in fact a call to an external non-python program. =] > Therefore, the loop must actually be mindlessly done. My question, however, > has been answered. > As an aside, why use range rather than xrange? I was under the impression > that xrange is a generator and therefore more memory efficient. > Probably because for small values (under 100), range just looks cleaner, and as far as memory goes it's not a whole lot of difference. AFAIK, Wayne -- To be considered stupid and to be told so is more painful than being called gluttonous, mendacious, violent, lascivious, lazy, cowardly: every weakness, every vice, has found its defenders, its rhetoric, its ennoblement and exaltation, but stupidity hasn’t. - Primo Levi ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Looping
Thank you. Func is in fact a call to an external non-python program. =] Therefore, the loop must actually be mindlessly done. My question, however, has been answered. As an aside, why use range rather than xrange? I was under the impression that xrange is a generator and therefore more memory efficient. On Mon, Apr 20, 2009 at 1:27 PM, Alan Gauld wrote: > "Matt" > wrote > > Let's say I want to run func 10 times Is there a more pythonic way to do >> it >> than this: >> for i in xrange(10): >> func() >> > > Yes, use range() rather than xrange :-) > > But more seriously, as others have pointed out, if func() is well > written then calling it ten times will have no effect over calling > it once. (Except taking up 10 times as much time!) > > Its like saying > > for n in range(10): > x = 42 > > The assignment is identical each time through the loop > > In fact it's worse than that because you don't even store the > result of func() so it has no effect whatsoever on your program > outside the loop. It would be more normal to do something like: > > for value in mycollection: > result = func(somevalue) > > in other words apply func() to each value in a collection. > > So unless your func() really takes arguments or prints time > related output or modifies global data (a bad practice) then > what you are asking doesn't make much sense. > > Finally, if your function is really a program in disguise - ie it > does all its own input/output then it would make more sense > to put the loop inside the function and put the repeat count > as a parameter: > > def func(repetitions): > for n in range(repetitions): ># your old func code here > > And call it: > > func(repetitions=10) # use keyword for clarity of purpose > > HTH, > > -- > Alan Gauld > Author of the Learn to Program web site > http://www.alan-g.me.uk/ > > ___ > Tutor maillist - Tutor@python.org > http://mail.python.org/mailman/listinfo/tutor > ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Looping
"Matt" wrote Let's say I want to run func 10 times Is there a more pythonic way to do it than this: for i in xrange(10): func() Yes, use range() rather than xrange :-) But more seriously, as others have pointed out, if func() is well written then calling it ten times will have no effect over calling it once. (Except taking up 10 times as much time!) Its like saying for n in range(10): x = 42 The assignment is identical each time through the loop In fact it's worse than that because you don't even store the result of func() so it has no effect whatsoever on your program outside the loop. It would be more normal to do something like: for value in mycollection: result = func(somevalue) in other words apply func() to each value in a collection. So unless your func() really takes arguments or prints time related output or modifies global data (a bad practice) then what you are asking doesn't make much sense. Finally, if your function is really a program in disguise - ie it does all its own input/output then it would make more sense to put the loop inside the function and put the repeat count as a parameter: def func(repetitions): for n in range(repetitions): # your old func code here And call it: func(repetitions=10) # use keyword for clarity of purpose HTH, -- Alan Gauld Author of the Learn to Program web site http://www.alan-g.me.uk/ ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Looping
Le Mon, 20 Apr 2009 17:26:30 +0200, "A.T.Hofkamp" s'exprima ainsi: > Matt wrote: > > Hey everyone, > > > > First post to this list. I hope I'm doing it right. > > > > Let's say I want to run func 10 times Is there a more pythonic way to do > > it than this: for i in xrange(10): > > func() > > no, that looks fine for your requirement. > > What may be a bit weird here is the requirement to run the same function 10 > times without further input/output parameters. I have never needed such a > construct. > What kind of function do you have that needs to be called 10 times? Actually, it's even rare to have to run a func n times, where n is known at runtime only. Builtin iteration (for item in container) removes 99% (about ;-) of such needs. Denis -- la vita e estrany ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Looping
Matt wrote: Hey everyone, First post to this list. I hope I'm doing it right. Let's say I want to run func 10 times Is there a more pythonic way to do it than this: for i in xrange(10): func() no, that looks fine for your requirement. What may be a bit weird here is the requirement to run the same function 10 times without further input/output parameters. I have never needed such a construct. What kind of function do you have that needs to be called 10 times? If you are doing timing experiments, the timeit library has a way of repeating the same experiment a number of times. Albert ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Looping
On Mon, Apr 20, 2009 at 8:48 AM, Matt > wrote: > Hey everyone, > > First post to this list. I hope I'm doing it right. > > Let's say I want to run func 10 times Is there a more pythonic way to do it > than this: > for i in xrange(10): > func() AFAIK that's the most pythonic way to do it... and probably how I'd do it... if I had a function I needed to run 10 times :P -Wayne ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Looping, and Win32com.client
Am Fri, 19 Dec 2008 15:57:49 +
schrieb Tim Golden :
> Eduardo Vieira wrote:
> > Hello, this is my first post in this list and I'm not a programmer,
> > but am enjoying learning python.
> > I'm trying to make a script to add worksheets to excel files:
> > I managed to implement this code:
> >
> > import os
> > folder = 'C:\\Personal\\oldxlsformat\\'
> > from win32com.client import Dispatch
> > xl = Dispatch('Excel.Application')
> > xl.Application.AskToUpdateLinks = "False"
> > for ficheiro in os.listdir(folder):
>
>
> os.listdir returns a list of files relative to
> the directory in question. (Try it at the
> interpreter and see). Excel requires, pretty
> much, a list of absolute filenames. So try
> using something like os.path.join (folder, ficheiro)
> when opening in Excel.
The above should be enough, but if problems persists, it's often
helpful in Win32 OSes to use the 8.3 filename:
shortname = win32api.GetShortPathName(os.path.join(folder, ficheiro))
Another alternative would be to use glob:
import glob
...
for ficheiro in glob.glob(os.path.join(folder, "*.xls")):
glob.glob returns the full path that was found.
Andreas
>
> TJG
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Re: [Tutor] Looping, and Win32com.client
Tim Golden wrote:
Eduardo Vieira wrote:
Hello, this is my first post in this list and I'm not a programmer,
but am enjoying learning python.
I'm trying to make a script to add worksheets to excel files:
I managed to implement this code:
import os
folder = 'C:\\Personal\\oldxlsformat\\'
from win32com.client import Dispatch
xl = Dispatch('Excel.Application')
xl.Application.AskToUpdateLinks = "False"
for ficheiro in os.listdir(folder):
os.listdir returns a list of files relative to
the directory in question. (Try it at the
interpreter and see). Excel requires, pretty
much, a list of absolute filenames.
Of course, I meant this it requires one absolute
filename, not a list :)
TJG
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Re: [Tutor] Looping, and Win32com.client
Thank you, now it worked! I made these changes to my code:
for ficheiro in os.listdir(folder):
file = os.path.join(folder, ficheiro) #added this
if ficheiro.endswith('.xls'):
wb = xl.Workbooks.Open(file, 2) # changed this
On Fri, Dec 19, 2008 at 8:57 AM, Tim Golden wrote:
> Eduardo Vieira wrote:
>>
>> Hello, this is my first post in this list and I'm not a programmer,
>> but am enjoying learning python.
>> I'm trying to make a script to add worksheets to excel files:
>> I managed to implement this code:
>>
>> import os
>> folder = 'C:\\Personal\\oldxlsformat\\'
>> from win32com.client import Dispatch
>> xl = Dispatch('Excel.Application')
>> xl.Application.AskToUpdateLinks = "False"
>> for ficheiro in os.listdir(folder):
>
>
> os.listdir returns a list of files relative to
> the directory in question. (Try it at the
> interpreter and see). Excel requires, pretty
> much, a list of absolute filenames. So try
> using something like os.path.join (folder, ficheiro)
> when opening in Excel.
>
> TJG
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Re: [Tutor] Looping, and Win32com.client
Eduardo Vieira wrote:
Hello, this is my first post in this list and I'm not a programmer,
but am enjoying learning python.
I'm trying to make a script to add worksheets to excel files:
I managed to implement this code:
import os
folder = 'C:\\Personal\\oldxlsformat\\'
from win32com.client import Dispatch
xl = Dispatch('Excel.Application')
xl.Application.AskToUpdateLinks = "False"
for ficheiro in os.listdir(folder):
os.listdir returns a list of files relative to
the directory in question. (Try it at the
interpreter and see). Excel requires, pretty
much, a list of absolute filenames. So try
using something like os.path.join (folder, ficheiro)
when opening in Excel.
TJG
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Re: [Tutor] Looping + Variables
James wrote:
> Hi. :)
>
> I'm trying to write a loop to simplify my life (and code :)). The
> loop is going to iterate over a list of values that I have to change
> in a file. I think my problem is better described with some code. :)
Use a dictionary instead of a tuple ...
# variables
editValues = {
"interface": "eth0",
"address": "192.168.1.5",
"mask": "255.255.255.0",
"gateway": "192.168.1.1"
}
> def replaceText( old , new , file ):
> for line in fileinput.FileInput( file , inplace = 1 ):
> line = line.replace( old , new )
> sys.stdout.write( line )
>
for key in editValues.keys():
replaceText('$' + key + '$' ,
editValues[key] , '/etc/conf.d/net' )
>
> config_$interface$=( "$address$ netmask $mask$" )
> routes_$interface$=( "default via $gateway$" )
Are you locked into this substitution format? If not, then how about
something like this:
# /etc/conf.d/net
config_%(interface)s=( "%(address)s netmask %(mask)s" )
routes_%(interface)s=( "default via %(gateway)s" )
You can then use python string formating (described here:
http://docs.python.org/lib/typesseq-strings.html), and pass the dict
directly. Note: if your file already contains '%' symbols that won't be
substituted, you must escape (prefix) them with an additional '%'.
valuedict = {
"interface": "eth0",
"address": "192.168.1.5",
"mask": "255.255.255.0",
"gateway": "192.168.1.1"
}
template = """\
# /etc/conf.d/net
config_%(interface)s=( "%(address)s netmask %(mask)s" )
routes_%(interface)s=( "default via %(gateway)s" )
"""
print template % valuedict
... prints ...
# /etc/conf.d/net
config_eth0=( "192.168.1.5 netmask 255.255.255.0" )
routes_eth0=( "default via 192.168.1.1" )
HTH,
Marty
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Re: [Tutor] looping problem
John Fouhy wrote:
> On 24/09/06, Python <[EMAIL PROTECTED]> wrote:
>> slices may be the best way to go
>> listA = biglist[0::3] # start from index 0 taking every third element
>> listB = biglist[2::3] # start from index 2 taking every third element
>
> I'm not certain they would be.. If you do that, you will:
>
> 1. Create a really big list.
> 2. Go through the list, taking every third element.
> 3. Go through the list again, taking every third+2 element.
>
> If the list is really big, step 1. might take some time and/or space,
> and you would like to avoid it.
That's a good point, though the OP didn't seem to have a problem with
memory.
>
> If we have:
>
> f2= open('myfile','r')
> listA = []
> listB = []
>
> then we can iterate through f2 as follows:
>
> for i, line in enumerate(f2):
> if i % 3 == 0 then
> listA.append(line)
> elif i % 3 == 2 then
> listB.append(line)
>
> This may be faster..
> (although I should like to see evidence before committing to that
> statement :-) )
Since the end goal seems to be to create a dictionary, there is really
no need to create the intermediate lists at all. You could do something
like this (following your file example):
d = {}
while 1:
try:
key, _, value = f2.next(), f2.next(), f2.next()
d[key] = value
except StopIteration:
pass
To do this with a list instead of a file use f2=iter(reallyBigList).
Kent
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Re: [Tutor] looping problem
On 24/09/06, Python <[EMAIL PROTECTED]> wrote:
> slices may be the best way to go
> listA = biglist[0::3] # start from index 0 taking every third element
> listB = biglist[2::3] # start from index 2 taking every third element
I'm not certain they would be.. If you do that, you will:
1. Create a really big list.
2. Go through the list, taking every third element.
3. Go through the list again, taking every third+2 element.
If the list is really big, step 1. might take some time and/or space,
and you would like to avoid it.
If we have:
f2= open('myfile','r')
listA = []
listB = []
then we can iterate through f2 as follows:
for i, line in enumerate(f2):
if i % 3 == 0 then
listA.append(line)
elif i % 3 == 2 then
listB.append(line)
This may be faster..
(although I should like to see evidence before committing to that
statement :-) )
--
John.
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Re: [Tutor] looping problem
kumar s wrote:
> hi,
>
> thank you. this is not a homework question.
>
> I have a very huge file of fasta sequence.
>
> I want to create a dictionary where 'GeneName' as key
> and sequence of ATGC characters as value
>
>
> biglist = dat.split('\t')
> ['GeneName ','','ATTAAGGCCAA'...]
>
> Now I want to select ''GeneName ' into listA
> and 'ATTAAGGCCAA' into listB
>
> so I want to select 0,3,6,9 elements into listA
> and 2,5,8,11 and so on elements into listB
>
> then I can do dict(zip(listA,listB))
>
> however, the very loops concept is getting blanked out
> in my brain when I want to do this:
>
> for j in range(len(biglist)):
> from here .. I cannot think anything..
>
> may be it is just mental block.. thats the reason I
> seek help on forum.
Lloyd has pointed you to slicing as the answer to your immediate
question. However for the larger question of reading FASTA files, you
might want to look at CoreBio, this is a new library of Python modules
for computational biology that looks pretty good.
http://code.google.com/p/corebio/
CoreBio has built-in support for reading FASTA files into Seq objects.
For example:
In [1]: import corebio.seq_io
In [2]: f=open(r'F:\Bio\BIOE48~1\KENTJO~1\SEQUEN~2\fasta\GI5082~1.FAS')
In [3]: seqs = corebio.seq_io.read(f)
seqs is now a list of Seq objects for each sequence in the original file
In this case there is only one sequence but it will work for your file also.
In [4]: for seq in seqs:
...: print seq.name
...: print seq
...:
...:
gi|50826|emb|CAA28242.1|
MIRTLLLSALVAGALSCGYPTYEVEDDVSRVVGGQEATPNTWPWQVSLQVLSSGRWRHNCGGSLVANNWVLTAAHCLSNYQTYRVLLGAHSLSNPGAGSAAVQVSKLVVHQRWNSQNVGNGYDIALIKLASPVTLSKNIQTACLPPAGTI
LPRNYVCYVTGWGLLQTNGNSPDTLRQGRLLVVDYATCSSASWWGSSVKSSMVCAGGDGVTSSCNGDSGGPLNCRASNGQWQVHGIVSFGSSLGCNYPRKPSVFTRVSNYIDWINSVMARN
In your case, you want a dict whose keys are the sequence name up to the
first tab, and the values are the actual sequences. Something like this
should work:
d = dict( (seq.name.split('\t')[0], seq) for seq in seqs)
The Seq class is a string subclass so putting the seq in the dict is
what you want.
There is also an iterator to read sequences one at a time, this might be
a little faster and more memory efficient because it doesn't have to
create the big list of all sequences. Something like this (untested):
from corebio.seq_io.fasta_io import iterseq
f = open(...)
d = dict( (seq.name.split('\t')[0], seq) for seq in iterseq(f))
Kent
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Re: [Tutor] looping problem
#!/usr/bin/python
# or whatever is the absolute path to python on your system
counter = 0
for i in "a","b","c","d","e","f","g" :
if counter%3 == 0 :
print i + " list one ", counter, counter%3
if counter%3 == 1 :
print i + " list two ", counter, counter%3
if counter%3 == 2 :
print i + " not used ", counter, counter%3
print "done"
On Sep 23, 2006, at 9:03 AM, kumar s wrote:
> hi,
>
> thank you. this is not a homework question.
>
> I have a very huge file of fasta sequence.
>
>> GeneName \t
> AATTAAGGAA..
>
> (1000 lines)
> AATAAGGA
>> GeneName \t
> GGAGAGAGATTAAGAA
> (15000 lines)
>
> when I read this as:
>
> f2= open('myfile','r')
> dat = f2.read().split('\n')
>
> turned out to be very expensive deal on computer.
>
> Instead I tried this:
>
> dat = f2.read()
>
> (reading into jumbo file of 19,100,442,1342 lines is
> easy but getting into what i want is a problem).
>
> I want to create a dictionary where 'GeneName' as key
> and sequence of ATGC characters as value
>
> biglist = dat.split('\t')
> ['GeneName ','','ATTAAGGCCAA'...]
>
> Now I want to select ''GeneName ' into listA
> and 'ATTAAGGCCAA' into listB
>
> so I want to select 0,3,6,9 elements into listA
> and 2,5,8,11 and so on elements into listB
>
> then I can do dict(zip(listA,listB))
>
> however, the very loops concept is getting blanked out
> in my brain when I want to do this:
>
> for j in range(len(biglist)):
> from here .. I cannot think anything..
>
> may be it is just mental block.. thats the reason I
> seek help on forum.
>
> Thanks
>
>
> --- jim stockford <[EMAIL PROTECTED]> wrote:
>
>> keep a counter in your loop. is this a homework
>> question?
>>
>> On Sep 23, 2006, at 8:34 AM, kumar s wrote:
>>
>>> hi,
>>>
>>> the reason could be that I did not quite
>> understand
>>> the concept of looping
>>>
>>> I have a list of 48 elements
>>>
>>> I want to create another two lists , listA and
>> listB
>>>
>>> I want to loop through the list with 48 elements
>> and
>>>
>>> select element with index 0,3,6,9,12 ..etc into
>> listA
>>>
>>> select elements with index 2,5,8,11 etc into
>> listB.
>>>
>>>
>>> Could any one help me how can I do that
>>>
>>> thankyou
>>>
>>> __
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>> protection around
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>>>
>>
>>
>
>
> __
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Re: [Tutor] looping problem
On Sat, 2006-09-23 at 09:03 -0700, kumar s wrote:
> hi,
>
> thank you. this is not a homework question.
>
> I have a very huge file of fasta sequence.
>
> > GeneName \t
> AATTAAGGAA..
>
>
>
>
>
> (1000 lines)
> AATAAGGA
> >GeneName \t
> GGAGAGAGATTAAGAA
> (15000 lines)
>
>
>
> when I read this as:
>
> f2= open('myfile','r')
> dat = f2.read().split('\n')
>
> turned out to be very expensive deal on computer.
>
>
> Instead I tried this:
>
> dat = f2.read()
>
> (reading into jumbo file of 19,100,442,1342 lines is
> easy but getting into what i want is a problem).
>
>
> I want to create a dictionary where 'GeneName' as key
> and sequence of ATGC characters as value
>
>
> biglist = dat.split('\t')
> ['GeneName ','','ATTAAGGCCAA'...]
>
> Now I want to select ''GeneName ' into listA
> and 'ATTAAGGCCAA' into listB
>
> so I want to select 0,3,6,9 elements into listA
> and 2,5,8,11 and so on elements into listB
>
> then I can do dict(zip(listA,listB))
>
>
>
> however, the very loops concept is getting blanked out
> in my brain when I want to do this:
>
> for j in range(len(biglist)):
> from here .. I cannot think anything..
slices may be the best way to go
listA = biglist[0::3] # start from index 0 taking every third element
listB = biglist[2::3] # start from index 2 taking every third element
>
> may be it is just mental block.. thats the reason I
> seek help on forum.
>
>
> Thanks
>
>
>
>
>
> --- jim stockford <[EMAIL PROTECTED]> wrote:
>
> >
> > keep a counter in your loop. is this a homework
> > question?
> >
> > On Sep 23, 2006, at 8:34 AM, kumar s wrote:
> >
> > > hi,
> > >
> > > the reason could be that I did not quite
> > understand
> > > the concept of looping
> > >
> > > I have a list of 48 elements
> > >
> > > I want to create another two lists , listA and
> > listB
> > >
> > > I want to loop through the list with 48 elements
> > and
> > >
> > > select element with index 0,3,6,9,12 ..etc into
> > listA
> > >
> > > select elements with index 2,5,8,11 etc into
> > listB.
> > >
> > >
> > > Could any one help me how can I do that
> > >
> > > thankyou
> > >
> > > __
> > > Do You Yahoo!?
> > > Tired of spam? Yahoo! Mail has the best spam
> > protection around
> > > http://mail.yahoo.com
> > > ___
> > > Tutor maillist - Tutor@python.org
> > > http://mail.python.org/mailman/listinfo/tutor
> > >
> >
> >
>
>
> __
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Re: [Tutor] looping problem
kumar s wrote: > [snip] > so I want to select 0,3,6,9 elements into listA > and 2,5,8,11 and so on elements into listB > > Here's a hint: for j in range(0, len(biglist), 3): # this will set j = 0, 3, 6, etc. -- Bob Gailer 510-978-4454 ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] looping problem
hi,
thank you. this is not a homework question.
I have a very huge file of fasta sequence.
> GeneName \t
AATTAAGGAA..
(1000 lines)
AATAAGGA
>GeneName \t
GGAGAGAGATTAAGAA
(15000 lines)
when I read this as:
f2= open('myfile','r')
dat = f2.read().split('\n')
turned out to be very expensive deal on computer.
Instead I tried this:
dat = f2.read()
(reading into jumbo file of 19,100,442,1342 lines is
easy but getting into what i want is a problem).
I want to create a dictionary where 'GeneName' as key
and sequence of ATGC characters as value
biglist = dat.split('\t')
['GeneName ','','ATTAAGGCCAA'...]
Now I want to select ''GeneName ' into listA
and 'ATTAAGGCCAA' into listB
so I want to select 0,3,6,9 elements into listA
and 2,5,8,11 and so on elements into listB
then I can do dict(zip(listA,listB))
however, the very loops concept is getting blanked out
in my brain when I want to do this:
for j in range(len(biglist)):
from here .. I cannot think anything..
may be it is just mental block.. thats the reason I
seek help on forum.
Thanks
--- jim stockford <[EMAIL PROTECTED]> wrote:
>
> keep a counter in your loop. is this a homework
> question?
>
> On Sep 23, 2006, at 8:34 AM, kumar s wrote:
>
> > hi,
> >
> > the reason could be that I did not quite
> understand
> > the concept of looping
> >
> > I have a list of 48 elements
> >
> > I want to create another two lists , listA and
> listB
> >
> > I want to loop through the list with 48 elements
> and
> >
> > select element with index 0,3,6,9,12 ..etc into
> listA
> >
> > select elements with index 2,5,8,11 etc into
> listB.
> >
> >
> > Could any one help me how can I do that
> >
> > thankyou
> >
> > __
> > Do You Yahoo!?
> > Tired of spam? Yahoo! Mail has the best spam
> protection around
> > http://mail.yahoo.com
> > ___
> > Tutor maillist - Tutor@python.org
> > http://mail.python.org/mailman/listinfo/tutor
> >
>
>
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Re: [Tutor] looping problem
keep a counter in your loop. is this a homework question? On Sep 23, 2006, at 8:34 AM, kumar s wrote: > hi, > > the reason could be that I did not quite understand > the concept of looping > > I have a list of 48 elements > > I want to create another two lists , listA and listB > > I want to loop through the list with 48 elements and > > select element with index 0,3,6,9,12 ..etc into listA > > select elements with index 2,5,8,11 etc into listB. > > > Could any one help me how can I do that > > thankyou > > __ > Do You Yahoo!? > Tired of spam? Yahoo! Mail has the best spam protection around > http://mail.yahoo.com > ___ > Tutor maillist - Tutor@python.org > http://mail.python.org/mailman/listinfo/tutor > ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Looping over lists of objects
On Mon, 24 Apr 2006, Etrade Griffiths wrote:
> just feeling my way into Python with a small app that reads data from
> file, creates objects using that data, stores the objects in a list,
> loops over the list doing comparison tests to filter out various
> objects. Here is a code snippet:
>
> class myObj:
>def __init__(self,a,b):
>self.a=a
>self.b=b
>
>def get_a(self):
>return self.a
>
>def get_b(self):
>return self.b
Hi Alun,
Looks ok so far.
Python specific tip: we can avoid writing getters and setters in Python.
Python supports an alternative way to control how clients set and get
attributes. If you're interested, look for information on Python
"properties". So for now, I'd recommend simplifying this to:
##
class myObj:
def __init__(self,a,b):
self.a=a
self.b=b
##
until we get into a real need to set up explicit get/set methods.
> # Read data from file
>
> L1=[]
> nobj=0
>
> for line in input:
>L0=line.split()
>a=L0[1]
>b=L0[2]
>nobj=nobj+1
>
>an_obj=myObj(a,b)
>
>L1.append(an_obj)
There must be additional context here, in the sense that I don't know what
'input' is. I suspect this is a file of some sort. So unfortunately, we
won't be able to test the exact same situation that you have.
I'd recommend turning this into a function as well, just to make the
commend superfluous:
##
def read_data_from_file(input):
L1=[]
nobj=0
for line in input:
L0=line.split()
a=L0[1]
b=L0[2]
nobj=nobj+1
an_obj=myObj(a,b)
L1.append(an_obj)
return L1, nobj
##
If we have this function, we can then test by doing:
#
L1, nobj = read_data_from_file(input)
#
and preserve the original behavior of our program. (We may want to do
some additional revision --- the nobj variable is also superfluous.)
> Trying to debug this using IDLE. The calls x.get_a and x.get_b always
> return zero so something is going wrong somewhere. I think I'm either
> not storing the objects correctly or retrieving them correctly but no
> idea why! All suggestions gratefully received!!!
I don't see anything horribly wrong with the code. There are at least two
possibilities when a problem comes up:
* There's something wrong with the program (which might be the case,
although I don't see it yet.)
* The input to the program is weird.
I'll assume, for the moment, that the input may be weird. *grin*
If we do have read_data_from_file() as function, we can test it by passing
it hardcoded "files", and see that we get the myObj values we expect.
Here's one test to start you off:
import StringIO
def test1():
sample_data = StringIO.StringIO("foo\tbar\tbaz\n")
objs, nobjs = read_data_from_input(sample_data)
assert (len(objs) == 1 == nobjs)
first_object = objs[0]
assert (first_object.a == "bar")
assert (first_object.b == "baz")
(This uses the very useful StringIO module to disguise a string to make it
look like a file. See:
http://www.python.org/doc/lib/module-StringIO.html)
Does this test case make sense to you?
If this test works out ok, then we've still made progress: we can at least
know that our parser is working well. That bolsters the possibility that
the input we're getting from our other source is weird.
Good luck to you.
___
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Re: [Tutor] Looping over lists of objects
Ed the problem is that my original code did not have the closing brackets for the method calls get_a and get_b whereas the code snippet I posted did. That's probably why your version works and mine failed. Thanks for your help! Alun At 17:19 24/04/2006, Ed Singleton wrote: >On 24/04/06, Etrade Griffiths <[EMAIL PROTECTED]> wrote: > > Hi > > > > just feeling my way into Python with a small app that reads data from > > file, creates objects using that data, stores the objects in a list, loops > > over the list doing comparison tests to filter out various > objects. Here is > > a code snippet: > > >[snip] > > > > Trying to debug this using IDLE. The calls x.get_a and x.get_b always > > return zero so something is going wrong somewhere. I think I'm either not > > storing the objects correctly or retrieving them correctly but no idea why! > > All suggestions gratefully received!!! > >I added some test input to give the code below, and it works fine for >me. Can you give us some test input that fails for you? Can you also >show us your test() function as it may the code in there that is >failing. > >Ed > >class myObj: > def __init__(self,a,b): > self.a=a > self.b=b > > def get_a(self): > return self.a > > def get_b(self): > return self.b > > >input = ["1 2 3", "4 5 6"] > >L1=[] >nobj=0 > >for line in input: > L0=line.split() > a=L0[1] > b=L0[2] > nobj=nobj+1 > > an_obj=myObj(a,b) > > L1.append(an_obj) > ># Filter data > >for i in range(1,nobj): > for x in L1:# ... loop over all objects in list > print "a -> ", x.get_a() # ... get value >of a from current object > print "b -> ", x.get_b() > > >It returns: > >a -> 2 >b -> 3 >a -> 5 >b -> 6 ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Looping over lists of objects
On 24/04/06, Etrade Griffiths <[EMAIL PROTECTED]> wrote: > Hi > > just feeling my way into Python with a small app that reads data from > file, creates objects using that data, stores the objects in a list, loops > over the list doing comparison tests to filter out various objects. Here is > a code snippet: > [snip] > > Trying to debug this using IDLE. The calls x.get_a and x.get_b always > return zero so something is going wrong somewhere. I think I'm either not > storing the objects correctly or retrieving them correctly but no idea why! > All suggestions gratefully received!!! I added some test input to give the code below, and it works fine for me. Can you give us some test input that fails for you? Can you also show us your test() function as it may the code in there that is failing. Ed class myObj: def __init__(self,a,b): self.a=a self.b=b def get_a(self): return self.a def get_b(self): return self.b input = ["1 2 3", "4 5 6"] L1=[] nobj=0 for line in input: L0=line.split() a=L0[1] b=L0[2] nobj=nobj+1 an_obj=myObj(a,b) L1.append(an_obj) # Filter data for i in range(1,nobj): for x in L1:# ... loop over all objects in list print "a -> ", x.get_a() # ... get value of a from current object print "b -> ", x.get_b() It returns: a -> 2 b -> 3 a -> 5 b -> 6 ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
