Re: [Tutor] Mobile apps in Python
I definitely recommend Kivy. I have enjoyed great success with it, and it was very easy to port my code to work on Android. ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] sql-like join on two lists or dictionaries
On 14/02/15 09:55, Peter Otten wrote:
with open(headerfile) as f:
lookup_header = {
headerdata[:6]: headerdata.rstrip(\n) for headerdata in f}
Then you can iterate over the lines in linefile, extract the key from that
and look it up in the dict:
with open(linefile) as lines, open(hl.dat, w) as joined:
for line in lines:
try:
header = lookup_header[line[:6]]
except KeyError:
header =
print(line.rstrip(\n), header, sep=, file=joined)
The try/except could be written more concisely as
header = lookup_header.get(line[:6], )
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] sql-like join on two lists or dictionaries
street.swee...@mailworks.org wrote:
Hello all,
Basically what I have here is header and line data for sales or purchase
orders, and I'm trying to do a sql-like join to bring them together
(which ultimately I did because I couldn't figure this out :)). I've
managed to get the files into python using string slicing, that's not a
problem.
headers - h.dat
B134542Bob ZQ775235
B875432Joe ZQ987656
B567943SteveZQ256222
lines - l.dat
B134542 112342 0012
B134542 176542 0001
B875732 765420003
B567943 654565 0001
B567943 900011 0001
desired result - hl.dat
B134542 112342 0012BobZQ775235
B134542 176542 0001BobZQ775235
B875732 765420003JoeZQ987656
B567943 654565 0001Steve ZQ256222
B567943 900011 0001Steve ZQ256222
in python3 on linux:
#!/usr/bin/env python3
import os
basepath=os.path.join(os.path.expanduser('~'),'temp',)
linefile=os.path.join(basepath,'l.dat')
headerfile=os.path.join(basepath,'h.dat')
with open(headerfile) as h, open(linefile) as l:
lines = l.readlines()
headers = h.readlines()
llist = [[linedata[0:7],
linedata[14:23],
linedata[23:27]] for linedata in lines]
hlist = [[headerdata[0:7],
headerdata[11:19],
headerdata[19:28]] for headerdata in headers]
ldict = [{linedata[0:7]:
[linedata[14:23],
linedata[23:27]]} for linedata in lines]
hdict = [{headerdata[0:7]:
[headerdata[11:19],
headerdata[19:28]]} for headerdata in headers]
# :)
quit()
Details on the data are that it's a one or many lines to one header
relationship, at least one of each will exist in each file, and
performance probably isn't an issue as it will only be a few tens to
about 100 lines maximum in the lines file. The match string will be the
0:7 slice.
You can probably guess my questions: should I be making lists or
dictionaries out of this data, and then of course, what should I do with
them to arrive at the combined file? I saw some examples of joining two
two-item lists, or dictionaries with a single string as the value, but I
couldn't seem to adapt them to what I'm doing here. I also ran across
the dict.extend method, but looking at the result, I didn't think that
was going to go anywhere, particularly with the one to many
headers:lines relationship.
After a while I pulled this into a sqlite file in memory and did the
join. Using writelines I think I'll be able to get it out to a file,
but it seems to me that there's probably a way to do this without
resorting to sql. Or is there?
You only need one dictionary that maps the first column in headerfile to the
complete line:
with open(headerfile) as f:
lookup_header = {
headerdata[:6]: headerdata.rstrip(\n) for headerdata in f}
Then you can iterate over the lines in linefile, extract the key from that
and look it up in the dict:
with open(linefile) as lines, open(hl.dat, w) as joined:
for line in lines:
try:
header = lookup_header[line[:6]]
except KeyError:
header =
print(line.rstrip(\n), header, sep=, file=joined)
This approach works with linefiles of arbitrary size as you only ever have
one line of that file in memory.
As written the output file includes lines with no matching header; replace
header =
with a
continue
statement to get an inner join.
A general remark: whenever possible you should avoid the readlines() method
which creates a list of lines and instead iterate over the file directly.
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Re: [Tutor] trivial simple program..can it be made more concise?
On 02/14/2015 04:07 AM, Steven D'Aprano wrote: On Sat, Feb 14, 2015 at 03:17:28AM +, steve10br...@comcast.net wrote: Hi all, I was playing with Python tonight and created a simple program that outputs numbers counting up then counting down all on the same terminal line. The code is as follows: # a = 32 #number to count up to for i in range (a): print i, '\r', for i in range ((a-1),0,-1): print i, '\r', # It works as desired. However, I was trying to figure out a way to make it more concise but cannot see a way since the 'range' parameters must be integers (no functions allowed?). Parameters to range can be anything which evaluates to integers, but I'm not sure how that will help you. Also, in Python 2 xrange is a little more efficient than range. How's this? a = 32 counts = (xrange(a), xrange(a-1, 0, -1)) for counter in counts: for i in counter: print i, '\r' BUT I'm not sure why you are worried about making it more concise when your code doesn't do what you want, as far as I can tell. You want the counter to be written on the same line, not 640 thousand lines, but when I try it, I get each number written to a different line. That's probably because you've dropped the trailing comma that the OP used in the print statements. Try this instead: import sys a = 32 counts = (xrange(a), xrange(a-1, 0, -1)) for counter in counts: for i in counter: sys.stdout.write(str(i) + '\r') sys.stdout.flush() -- DaveA ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] trivial simple program..can it be made more concise?
On Sat, Feb 14, 2015 at 06:40:56AM -0500, Dave Angel wrote: On 02/14/2015 04:07 AM, Steven D'Aprano wrote: On Sat, Feb 14, 2015 at 03:17:28AM +, steve10br...@comcast.net wrote: [...] for i in range (a): print i, '\r', [...] BUT I'm not sure why you are worried about making it more concise when your code doesn't do what you want, as far as I can tell. You want the counter to be written on the same line, not 640 thousand lines, but when I try it, I get each number written to a different line. That's probably because you've dropped the trailing comma that the OP used in the print statements. So I did :-( Have I mentioned recently just how awesome Python 3's print is? for i in range(10): print(i, end='\r') Much nicer :-) -- Steve ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] sql-like join on two lists or dictionaries
On Sat, Feb 14, 2015 at 8:03 AM, Alan Gauld alan.ga...@btinternet.com
wrote:
On 14/02/15 09:55, Peter Otten wrote:
with open(headerfile) as f:
lookup_header = {
headerdata[:6]: headerdata.rstrip(\n) for headerdata in f}
Then you can iterate over the lines in linefile, extract the key from that
and look it up in the dict:
with open(linefile) as lines, open(hl.dat, w) as joined:
for line in lines:
try:
header = lookup_header[line[:6]]
except KeyError:
header =
print(line.rstrip(\n), header, sep=, file=joined)
The try/except could be written more concisely as
header = lookup_header.get(line[:6], )
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
You can dispense with the slicing if you use the str.split() method. It
will put each item in a list.
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--
Joel Goldstick
http://joelgoldstick.com
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Re: [Tutor] trivial simple program..can it be made more concise?
On 02/14/2015 07:51 AM, Steven D'Aprano wrote: On Sat, Feb 14, 2015 at 06:40:56AM -0500, Dave Angel wrote: On 02/14/2015 04:07 AM, Steven D'Aprano wrote: On Sat, Feb 14, 2015 at 03:17:28AM +, steve10br...@comcast.net wrote: [...] for i in range (a): print i, '\r', [...] BUT I'm not sure why you are worried about making it more concise when your code doesn't do what you want, as far as I can tell. You want the counter to be written on the same line, not 640 thousand lines, but when I try it, I get each number written to a different line. That's probably because you've dropped the trailing comma that the OP used in the print statements. So I did :-( Have I mentioned recently just how awesome Python 3's print is? for i in range(10): print(i, end='\r') Much nicer :-) Agreed. But don't you need \r so when you're counting down you don't have the trailing crud? The space was implicit on Python 2, because it mistakenly thought the code was printing two elements. -- DaveA ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
[Tutor] Mobile apps in Python
I am a fairly new student of Python, and so far I've been impressed with the speed,ease and comfort of it. In the near future, I would like to build 3d graphical mobile games. Is there any platform out there that would allow me to build 3d mobile apps using the Python language exclusively? Thanks in advance ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Mobile apps in Python
On Sat, Feb 14, 2015 at 05:12:59PM -0500, Unee0x wrote: I am a fairly new student of Python, and so far I've been impressed with the speed,ease and comfort of it. In the near future, I would like to build 3d graphical mobile games. Is there any platform out there that would allow me to build 3d mobile apps using the Python language exclusively? Oh, if only there were a website where you could type in simple queries and have the website search the entire Internet for an answer! https://duckduckgo.com/html/?q=how+to+search+the+internet http://www.google.com.au/search?q=how+to+search+the+internet *wink* If you search for Python mobile apps, e.g. using this: https://startpage.com/do/search/?q=Python+mobile+apps then the top search result that comes up is for Kivy: http://kivy.org/ which is probably the most popular of the mobile app frameworks for Python. Searching for 3D apps: http://www.bing.com/search?q=python+3d+mobile+apps also suggests PyMob and QPython. -- Steve ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] trivial simple program..can it be made more concise?
On Sat, Feb 14, 2015 at 03:17:28AM +, steve10br...@comcast.net wrote: Hi all, I was playing with Python tonight and created a simple program that outputs numbers counting up then counting down all on the same terminal line. The code is as follows: # a = 32 #number to count up to for i in range (a): print i, '\r', for i in range ((a-1),0,-1): print i, '\r', # It works as desired. However, I was trying to figure out a way to make it more concise but cannot see a way since the 'range' parameters must be integers (no functions allowed?). Parameters to range can be anything which evaluates to integers, but I'm not sure how that will help you. Also, in Python 2 xrange is a little more efficient than range. How's this? a = 32 counts = (xrange(a), xrange(a-1, 0, -1)) for counter in counts: for i in counter: print i, '\r' BUT I'm not sure why you are worried about making it more concise when your code doesn't do what you want, as far as I can tell. You want the counter to be written on the same line, not 640 thousand lines, but when I try it, I get each number written to a different line. Try this instead: import sys a = 32 counts = (xrange(a), xrange(a-1, 0, -1)) for counter in counts: for i in counter: sys.stdout.write(str(i) + '\r') sys.stdout.flush() -- Steve ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
[Tutor] sql-like join on two lists or dictionaries
Hello all,
Basically what I have here is header and line data for sales or purchase
orders, and I'm trying to do a sql-like join to bring them together
(which ultimately I did because I couldn't figure this out :)). I've
managed to get the files into python using string slicing, that's not a
problem.
headers - h.dat
B134542Bob ZQ775235
B875432Joe ZQ987656
B567943SteveZQ256222
lines - l.dat
B134542 112342 0012
B134542 176542 0001
B875732 765420003
B567943 654565 0001
B567943 900011 0001
desired result - hl.dat
B134542 112342 0012BobZQ775235
B134542 176542 0001BobZQ775235
B875732 765420003JoeZQ987656
B567943 654565 0001Steve ZQ256222
B567943 900011 0001Steve ZQ256222
in python3 on linux:
#!/usr/bin/env python3
import os
basepath=os.path.join(os.path.expanduser('~'),'temp',)
linefile=os.path.join(basepath,'l.dat')
headerfile=os.path.join(basepath,'h.dat')
with open(headerfile) as h, open(linefile) as l:
lines = l.readlines()
headers = h.readlines()
llist = [[linedata[0:7],
linedata[14:23],
linedata[23:27]] for linedata in lines]
hlist = [[headerdata[0:7],
headerdata[11:19],
headerdata[19:28]] for headerdata in headers]
ldict = [{linedata[0:7]:
[linedata[14:23],
linedata[23:27]]} for linedata in lines]
hdict = [{headerdata[0:7]:
[headerdata[11:19],
headerdata[19:28]]} for headerdata in headers]
# :)
quit()
Details on the data are that it's a one or many lines to one header
relationship, at least one of each will exist in each file, and
performance probably isn't an issue as it will only be a few tens to
about 100 lines maximum in the lines file. The match string will be the
0:7 slice.
You can probably guess my questions: should I be making lists or
dictionaries out of this data, and then of course, what should I do with
them to arrive at the combined file? I saw some examples of joining two
two-item lists, or dictionaries with a single string as the value, but I
couldn't seem to adapt them to what I'm doing here. I also ran across
the dict.extend method, but looking at the result, I didn't think that
was going to go anywhere, particularly with the one to many
headers:lines relationship.
After a while I pulled this into a sqlite file in memory and did the
join. Using writelines I think I'll be able to get it out to a file,
but it seems to me that there's probably a way to do this without
resorting to sql. Or is there?
Thanks!
___
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