Re: [Tutor] Help

[David Palao]

2016-06-28 7:54 GMT+02:00 Aaron Johnson :
> I have a program that is telling my i need your digital snake, but i dont
> want a snake. Help
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I think you have to decide. I see two options:
1) keep obeying your program. That sounds a bit hazardous to me.
Consider that the 3 laws of robotics apply to machines not to humans!
2) Ignore your program.
You ask for help. My suggestion is: take 2).

Best
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Re: [Tutor] Root and power

[David Palao]

2015-07-29 5:29 GMT+02:00 Job Hernandez jobrh2...@gmail.com:
 How is it going tutors?

 The following problem seems impossible to me:

 *Write a program that asks the user to enter an integer and prints two
 integers, root and pwr, such that 0  pwr  6 and root^pwr (root**pwr) is
 equal to the integer entered by the user. If no such pair of integers
 exists, it should print a message to that effect*.

 I would like to solve this problem myself so please don't give me the
 solution.

  I need to learn how in the world do find the root and power of an integer
 that x user entered? I haven been looking on the python website for an
 appropriate function but I have not.

 If you have the time can you please tell me about the functions and other
 facts I need to know in order to solve this problem?

 Is there a book you guys recommend for total beginners who have no ideal of
 what computer science and programming is?

 Thank you,

 Job
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Hello,
First, you need an algorithm that solves your problem. Once you have
it, you need to implement it in Python.
For the algorithm. Although there are theorems and all sort of smart
mathematical tricks you could use, given the conditions you have, have
you considered to use a brute force approach? I mean: if all involved
numbers are positive you could start testing different values for root
from 0 on, and for each value test pwr from 1 to 5 until you find
either a solution, something bigger than x.
Once you chose the algorithm, for the actual implementation you have
to say what part you are blocked at.
Best.
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Re: [Tutor] Should error checking be duplicated for both functions if one function calls another one?

[David Palao]

Hello,
Not sure if I got it, but, in my opinion functions should do only one
thing.So if function 2 finds an error, it should raise it. There
should be another function  (function 1 in your case?) taking care of
possible raised errors.

Best

2015-06-01 16:27 GMT+02:00 boB Stepp robertvst...@gmail.com:
 Suppose in a given state of a program, function 1 calls function 2.
 Function 1 includes checks for possible error conditions. If there are
 no issues, then function 2 should execute with no issues as well. The
 question is, should function 2 include the error checking done in
 function 1 if function 2 is only ever called by function 1?

 My inclination is to say yes, as in some future incarnation of the
 program function 2 might get called in new ways. What are your
 thoughts?

 --
 boB
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Re: [Tutor] Function not returning 05 as string

[David Palao]

Hello,
In the code that you posted, as it is, you are:
1) defining a function (numberentry)
2) defining a global variable (number01) and setting it to 0
3) calling numberentry discarding the result
4) printing the value of the global variable number01

I would guess that you want to store the result of the function and
print it. Is that correct?

Best

2015-04-13 14:11 GMT+02:00 Ken G. beachkid...@gmail.com:
 I am sure there is an simple explanation but when I input
 5 (as integer), resulting in 05 (as string), I get zero as the end
 result. When running the code:

 START OF PROGRAM:
 Enter the 1st number:  5

 05

 0
 END OF PROGRAM:

 START OF CODE:
 import sys

 def numberentry():
 print
 number01 = raw_input(Enter the 1st number:  )
 if number01 == 0:
 sys.exit()
 if  len(number01) == 1:
 number01 = 0 + number01
 print
 print number01
 return(number01)

 number01 = 0
 numberentry()
 print
 print number01
 END OF CODE:
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Re: [Tutor] While truth

[David Palao]

Hi,
6, -1 or 0 are not bools (True or False):
 6 is True
False

 0 is False
False
 If you had to design a language and want to think about using numbers
in a logical context you could do at least two things:
1) convert the number to bool, ie define a set of rules to assign to
each number a logical value, or
2) don't convert and raise an error.
In python, like in many other languages, option 1) has been chosen.
The rules are roughly: when using a number in a logical context 0 is
casted to False, and the other numbers are considered True.
The while statement expects an expression that returns a logical
value. Put both things together and I think you get your answer, if I
well understood.
Best

2014-05-20 10:25 GMT+02:00 Ian D dux...@hotmail.com:
 I was reading a tutorial that had these examples in it:


 while False:

   print(False is the new True.)


 while 6:

   print(Which numbers are True?)


 while -1:

   print(Which numbers are True?)


 while 0:

   print(Which numbers are True?)



 Unfortunately the author never explained these statements.


 I was wondering if the gist of a while statement could be explained in the 
 context of these examples.


 e.g. while False:


 means while True is False, which is never True because True is of course True 
 not False.


 but while 6:


 means. err while 6 is True? and this is True because... err.


 Anyway I am a  bit lost with this.


 Can anyone shed any light please?


 Thanks.
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Re: [Tutor] Inheritance in classes

[David Palao]

2014-04-08 7:44 GMT+02:00 Santosh Kumar rhce@gmail.com:
 Can i mask the parent attibutes in the child. let me give a quick example.

 In [1]: class a:
...: value1 = 1
...: value2 = 2
...:

 In [2]: class b(a):
...: value3 = 3
...:

 In [3]: obj1 = b()

 In [4]: obj1.value1
 Out[4]: 1

 In [5]: obj1.value2
 Out[5]: 2

 In [6]: obj1.value3
 Out[6]: 3

 If you notice in the below example you will see that the child class object
 ``obj1`` has inherited all the attibutes of the parent class. Is there a way
 by which i can make the child class not inherit some of the properites of
 parent class.


 --
 D. Santosh Kumar



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Hi,
This is the default behaviour. You can ovrcome that, but it will
require extra work. For instance you could make use of pseudoprivate
attributes (any attribute starting with double underscore, but not
ending with dtwo underscores); or some managing attributes tool:
*) __getattr__, __getattribute__ are generic ways to manage attribute fetching
*) properties and descriptors allow a more specific way to control
attributes (one by one)
But, be careful. These tools can be very tricky at first.
Hope it helps.

Best
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Re: [Tutor] Help Noob Question

[David Palao]

Hello,
What do you mean by open it in the interpreter?
Do you want to open it and read from it its content? or do you want to
execute its python code within the interpreter?
Best

2014-03-27 7:43 GMT+01:00 Leo Nardo waterfallr...@gmail.com:
 Im on windows 8 and i need to open a file called string1.py that is on my
 desktop, in both the interpreter and notepad++, so that i can work on it. I
 already have it open in notepad, but for the life of me cannot figure out
 how to open it in the interpreter. Invalid syntax is the error message when
 i type in python string1.py into the interpreter! maybe a dumb
 question but i would appreciate the help for sure. thanks :)

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Re: [Tutor] When to use multiprocessing Managers?

[David Palao]

2014-02-25 11:52 GMT+01:00 James Chapman ja...@uplinkzero.com:
 Hello tutors

 I'm curious about managers and when to use them.
 For example, I see they offer a Queue() for sharing a Q between
 processes, but if I create a Q in the parent process and pass it down
 to child processes, then they can put messages into that Q just fine,
 and I presume the same thing for other objects available under the
 managers package.

 So unless the other process is on a different machine, is there a
 reason to use a manager?

 Does anyone have any use case examples or snippets I could look at even?

 Thanks in advance
 James
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Hello,
I asked myself the same question when I started using multiprocessing
time ago. So I was very happy when I saw the question by James.

From my limited knowledge, I would say that a Manager can be useful
when processes are distributed across different hosts, or if the
exchange of information between processes is more complex than just a
couple of synchronization primitives.

Best
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Re: [Tutor] from command prompt use interactive python and running script together

[David Palao]

2014-02-21 15:20 GMT+01:00 Gabriele Brambilla gb.gabrielebrambi...@gmail.com:
 Hi,

 Is possible on python to running scripts from the command prompt (I'm using
 python on windows) and in the end saving all the variables and continue the
 analysis in the interactive mode? (the one that you activate typing python
 in the command prompt?)

I guess you could define a function that does something like this by
using pickle or similar technology.

 Or to use python in the interactive mode and in some moments to run scripts,
 without quit() the interactive mode, and use for the script variables the
 one you have defined in the interactive mode?


You could import some objects from modules and use them in the
interactive session.


 thanks

 Gabriele


Best

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Re: [Tutor] for: how to skip items

[David Palao]

Hi Gabriele,
Without knowing the details of what you are trying, I guess you could
be interested in looking at how to define your own iterators.

Regards

2014-02-17 17:05 GMT+01:00 Gabriele Brambilla gb.gabrielebrambi...@gmail.com:
 Hi,

 I'm wondering how I can (if I can) make a for loop in which I don't use all
 the elements.

 for example

 a100 = list(range(100))

 for a in a100:
  print(a)

 it print out to me all the numbers from 0 to 99
 But if I want to display only the numbers 0, 9, 19, 29, 39, ...(one every 10
 elements) how can I do it WITHOUT defining a new list (my real case is not
 so simple) and WITHOUT building a list of indexes?

 thank you

 Gabriele

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Re: [Tutor] second if

[David Palao]

Also, could you explain better what is your doubt? You don't
understand what index = 1 means, or why this if at this point, or
anything else?

Best

2014-02-07 17:14 GMT+01:00 rahmad akbar matbioi...@gmail.com:
 he guys, i am trying to understand this code: i understand the first if
 statement (if line.startswith..) in read_fasta function but couldnt
 understand the next one(if index =...). thanks in advance!!

 import sys
 #class declaration with both attributes we need
 class Fasta:
 def __init__(self, name, sequence):
 #this will store the sequence name
 self.name = name
 #this  will store the sequence itself
 self.sequence = sequence

 #this function will receive the list with the file
 #contents, create instances of the Fasta class as
 #it scans the list, putting the sequence name on the
 #first attribute and the sequence itself on the second
 #attribute
 def read_fasta(file):
 #we declare an empty list that will store all
 #Fasta class instances generated
 items = []
 index = 0
 for line in file:
 #we check to see if the line starts with a  sign
 if line.startswith():
#if so and our counter is large than 1
#we add the created class instance to our list
#a counter larger than 1 means we are reading
#from sequences 2 and above
if index = 1:
items.append(aninstance)
index+=1
#we add the line contents to a string
name = line[:-1]
#and initialize the string to store the sequence
seq = ''
#this creates a class instance and we add the attributes
#which are the strings name and seq
aninstance = Fasta(name, seq)
 else:
#the line does not start with  so it has to be
#a sequence line, so we increment the string and
#add it to the created instance
 seq += line[:-1]
 aninstance = Fasta(name, seq)

 #the loop before reads everything but the penultimate
 #sequence is added at the end, so we need to add it
 #after the loop ends
 items.append(aninstance)
 #a list with all read sequences is returned
 return items

 fastafile = open(sys.argv[1], 'r').readlines()
 mysequences = read_fasta(fastafile)

 print mysequences

 for i in mysequences:
 print i.name

 --
 many thanks
 mat

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Re: [Tutor] second if

[David Palao]

I guess the replies by Alan and Peter precisely answer to your question?

Best

2014-02-10 12:46 GMT+01:00 rahmad akbar matbioi...@gmail.com:
 David,

 thanks for your reply. i cant figure out why the if at that point and what
 is the 'if' try to accompolish


 On Mon, Feb 10, 2014 at 11:52 AM, David Palao dpalao.pyt...@gmail.com
 wrote:

 Also, could you explain better what is your doubt? You don't
 understand what index = 1 means, or why this if at this point, or
 anything else?

 Best

 2014-02-07 17:14 GMT+01:00 rahmad akbar matbioi...@gmail.com:
  he guys, i am trying to understand this code: i understand the first if
  statement (if line.startswith..) in read_fasta function but couldnt
  understand the next one(if index =...). thanks in advance!!
 
  import sys
  #class declaration with both attributes we need
  class Fasta:
  def __init__(self, name, sequence):
  #this will store the sequence name
  self.name = name
  #this  will store the sequence itself
  self.sequence = sequence
 
  #this function will receive the list with the file
  #contents, create instances of the Fasta class as
  #it scans the list, putting the sequence name on the
  #first attribute and the sequence itself on the second
  #attribute
  def read_fasta(file):
  #we declare an empty list that will store all
  #Fasta class instances generated
  items = []
  index = 0
  for line in file:
  #we check to see if the line starts with a  sign
  if line.startswith():
 #if so and our counter is large than 1
 #we add the created class instance to our list
 #a counter larger than 1 means we are reading
 #from sequences 2 and above
 if index = 1:
 items.append(aninstance)
 index+=1
 #we add the line contents to a string
 name = line[:-1]
 #and initialize the string to store the sequence
 seq = ''
 #this creates a class instance and we add the attributes
 #which are the strings name and seq
 aninstance = Fasta(name, seq)
  else:
 #the line does not start with  so it has to be
 #a sequence line, so we increment the string and
 #add it to the created instance
  seq += line[:-1]
  aninstance = Fasta(name, seq)
 
  #the loop before reads everything but the penultimate
  #sequence is added at the end, so we need to add it
  #after the loop ends
  items.append(aninstance)
  #a list with all read sequences is returned
  return items
 
  fastafile = open(sys.argv[1], 'r').readlines()
  mysequences = read_fasta(fastafile)
 
  print mysequences
 
  for i in mysequences:
  print i.name
 
  --
  many thanks
  mat
 
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 --
 many thanks
 mat
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Re: [Tutor] good django book?

[David Palao]

Hi,
The Django community has plenty of good information in the web.
I would go there and have a look. At least this is what I did,
precisely for the same reason that you mention.
Best,

David

2014-02-06 Christopher Spears cspears2...@yahoo.com:
 Can anyone recommend a good Django book?  I have been looking on Amazon, and 
 the books seem to be out of date.

 Thanks,
 Chris
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Re: [Tutor] Changing only intergers in a list of strings

[David Palao]

Hi,
Is it not clear to me if you must distinguish ints from other type of
numbers, or if, for instances floats and ints must be dealt
differently.
Anyway, I would propose something like the following function:

def FindNumbers(a_string):
print You entered:, a_string
out_list = []
for item in a_string.split():
try:
num = int(item)
except ValueError:
out_list.append(item)
else:
out_list.append(%s % (num+a,))
out_string = ' '.join(out_list)
# do whatever you want to do with the resulting out_string:
return it, or display it...

Some comments:
1) I would pass the input string as argument rather than using it as a global.
2) You could use float instead of int to make it more general
3) If you need to distinguish between ints and floats, then you must
add a couple of extra lines

I hope it helps.

Best


2014-02-04 Colin Struthers 303cookiemons...@gmail.com:
 I am in a beginning python course and am working through some code and I
 can't even figure out how to start building this particular section of code.

 My goal is to get a sentence for the user and to take each number in the
 user string and add 1 to each number. i.e the 4 people had 6 dogs would
 change to the 5 people had 7 dogs

 a_string = [ ]
 int_list = [ ]
 a_string = raw_input(Enter a sentence with both words and numbers: )

 def FindNumbers():
 print You entered: , a_string
 for ints in a_string
 ...?

 FindNumbers()

 I fully understand that this doesn't even begin to work but I don't really
 know where to start deconstructing the list, editing only the intergers, and
 joining it all back together.

 Thanks for the help.

 --
 Colin

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Re: [Tutor] Changing only intergers in a list of strings

[David Palao]

Sorry, there is a typo:
(num+a,) should be (num+1,), obviously.

2014-02-05 David Palao dpalao.pyt...@gmail.com:
 Hi,
 Is it not clear to me if you must distinguish ints from other type of
 numbers, or if, for instances floats and ints must be dealt
 differently.
 Anyway, I would propose something like the following function:

 def FindNumbers(a_string):
 print You entered:, a_string
 out_list = []
 for item in a_string.split():
 try:
 num = int(item)
 except ValueError:
 out_list.append(item)
 else:
 out_list.append(%s % (num+a,))
 out_string = ' '.join(out_list)
 # do whatever you want to do with the resulting out_string:
 return it, or display it...

 Some comments:
 1) I would pass the input string as argument rather than using it as a global.
 2) You could use float instead of int to make it more general
 3) If you need to distinguish between ints and floats, then you must
 add a couple of extra lines

 I hope it helps.

 Best


 2014-02-04 Colin Struthers 303cookiemons...@gmail.com:
 I am in a beginning python course and am working through some code and I
 can't even figure out how to start building this particular section of code.

 My goal is to get a sentence for the user and to take each number in the
 user string and add 1 to each number. i.e the 4 people had 6 dogs would
 change to the 5 people had 7 dogs

 a_string = [ ]
 int_list = [ ]
 a_string = raw_input(Enter a sentence with both words and numbers: )

 def FindNumbers():
 print You entered: , a_string
 for ints in a_string
 ...?

 FindNumbers()

 I fully understand that this doesn't even begin to work but I don't really
 know where to start deconstructing the list, editing only the intergers, and
 joining it all back together.

 Thanks for the help.

 --
 Colin

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Re: [Tutor] reading files

[David Palao]

2014-01-29 Mark Lawrence breamore...@yahoo.co.uk:
 On 29/01/2014 14:50, Gabriele Brambilla wrote:

 thanks to everyone, I've used David's method.

 Gabriele

 2014-01-29 Mark Lawrence breamore...@yahoo.co.uk
 mailto:breamore...@yahoo.co.uk


 On 29/01/2014 02:09, Gabriele Brambilla wrote:

 Hi,
 how could I read float numbers if the data format is like this
 (using
 readline):

 1.0551951.26758123387023-0.314470329249235
 -0.293015360064208  6.157957619078221.92919102133526
 13.07804596303782.15175351758512e6

 the numbers aren't equally spaced and they had not the same
 number of
 figures...

 thanks

 Gabriele


 Something like this, untested:-

 floats = []
 with open('myfile') as infile:
  for line in infile:
  floats.extend(float(f) for f in line.split())

 --
 My fellow Pythonistas, ask not what our language can do for you, ask
 what you can do for our language.

 Mark Lawrence


 Please don't top post.

 FTR what is David's method and who is David?


 --
 My fellow Pythonistas, ask not what our language can do for you, ask what
 you can do for our language.

 Mark Lawrence

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I guess he refers to my email, the first answer to his question.

Best regards.
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[Tutor] Fwd: reading files

[David Palao]

...that I forgot to send to the mailing list...


-- Forwarded message --
From: David Palao dpalao.pyt...@gmail.com
Date: 2014-01-29
Subject: Re: [Tutor] reading files
To: Gabriele Brambilla gb.gabrielebrambi...@gmail.com


Hi,
One possibility I can think of: If you make one string with one line
of your input, like
s = 1.0551951.26758123387023
-0.314470329249235 -0.293015360064208  6.15795761907822
1.92919102133526 13.07804596303782.15175351758512e6
then
L = [float(i) for i in s.split()]
is a list of the floats you are looking for.

Best.

2014-01-29 Gabriele Brambilla gb.gabrielebrambi...@gmail.com:
 Hi,
 how could I read float numbers if the data format is like this (using
 readline):

 1.0551951.26758123387023-0.314470329249235
 -0.293015360064208  6.157957619078221.92919102133526
 13.07804596303782.15175351758512e6

 the numbers aren't equally spaced and they had not the same number of
 figures...

 thanks

 Gabriele

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Re: [Tutor] question about the an exercise in core python programing (including the discription about the exercise)

[David Palao]

Hi,
some hints:
1) strings are iterables
2) help(zip)
3) help(enumerate)

Best regards.

2012/1/4 daedae11 daeda...@126.com

 **
 Who can give me an example program about the exercise 6 in chapter 9 in
 core python programming ?

 The exercise is:
 Write a program that compare the two files given by users. If the two
 files' content is equal, just print equal. Else, print the rows And
 column number of the first different position.

 Thank you!





 Thank you!

 --
 daedae11

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