List comprehensions

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October 18th, 2012, 07:48 PM

Nick Wyden

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List comprehensions

Hello, what I am trying to do is change the user input to all caps just for practice with list comprehensions. But as soon as I enter some input the program quits. So I am like

here is my code

Code:

input_string = str(input(' your letters here: ')) 

[chars.upper() for chars in input_string]

thanks for your help

October 18th, 2012, 08:57 PM

b49P23TIvg

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It works. Note that in python3 input returns a string, so str(input()) is a bit wasteful. Now, if you're trying to run this as a module and you want to see the result you'd need to explicitly print result of the expression.
print([chars.upper() for chars in input_string])

Code:

$ python3
Python 3.2.3 (default, Sep 10 2012, 18:14:40) 
[GCC 4.6.3] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> input_string = str(input(' your letters here: ')) 
 your letters here: a;kjas;lkf
>>> [chars.upper() for chars in input_string] 
['A', ';', 'K', 'J', 'A', 'S', ';', 'L', 'K', 'F']
>>>

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October 19th, 2012, 04:22 PM

Dietrich

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If you don't use the Python shell, you may need to add a wait:

Code:

# Python3 syntax

input_string = input(' your letters here: ') 

print([chars.upper() for chars in input_string])

# wait for user response
input("Press Enter to go on ...")

Comments on this post

b49P23TIvg disagrees: learn to configure your DOS window so that it doesn't exit rather than writing incompatible
programs.

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October 20th, 2012, 08:38 PM

Nick Wyden

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this forum is great thanks

but how do I get the string returned to just be the characters for example

if I enter 'hi' it would return
['H','I']

but I want it to return

HI

any ideas?

Last edited by Nick Wyden : October 20th, 2012 at 08:43 PM. Reason: I wanted to add one other question

October 20th, 2012, 08:46 PM

b49P23TIvg

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study your string methods.

''.join(iterable_of_strings)

October 20th, 2012, 09:51 PM

Nick Wyden

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can you post some links about string methods?

October 21st, 2012, 08:08 AM

b49P23TIvg

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Post links about string methods?
Bookmark www.python.org

strings in the official python tutorial

Official documents, text sequences

The string module

How to represent a string

There's a lot of other useful information at docs.python.org .

Also, help is available on just about everything in python. For instance, in the interpreter:

>>> help('')

Quote:

Originally Posted by docs.python.org

Library Reference
keep this under your pillow

Last edited by b49P23TIvg : October 21st, 2012 at 08:10 AM.