comparing user input against a string (newbie)

Dev Shed Forums Sponsor:

March 13th, 2004, 12:14 AM

member009

Registered User

Join Date: Mar 2004

Posts: 2

Time spent in forums: < 1 sec
Reputation Power: 0

comparing user input against a string (newbie)

Hi, i'm trying to break out of a loop whenever user type in "q".
However if ui=="q": never return true when i type in "q"!?!?
what is the reason?

while:
print "Pls input the nominated text: "
ui = str(sys.stdin.readline())
if ui=="q":
break

March 13th, 2004, 02:29 AM

dmills

Registered User

Join Date: Mar 2004

Posts: 5

Time spent in forums: < 1 sec
Reputation Power: 0

Re: comparing user input against a string (newbie)

I believe the problem is that sys.stdin.readline() will read in the whole line, including the carriage return ("\n") at the end. According to the Python docs:

Quote:

readline( [size])
Read one entire line from the file. A trailing newline character is kept in the string (but may be absent when a file ends with an incomplete line).

If you wish to remove the newline character try rstrip(). Here's your code modified to (hopefully) work:

Code:

while 1:  
     print "Pls input the nominated text: "  
     ui = sys.stdin.readline()  
     ui = ui.rstrip("\n")
     if ui=="q":  
          break

March 13th, 2004, 02:54 AM

percivall

Contributing User

Join Date: Jul 2003

Posts: 133

Time spent in forums: < 1 sec
Reputation Power: 10

An easier way is probably to use the function raw_input(). It will strip the newline from the input.

March 13th, 2004, 09:03 AM

netytan

Hello World :)

Join Date: Mar 2003

Location: Hull, UK

Posts: 2,537

Time spent in forums: 1 Week 2 Days 18 h 17 m 47 sec
Reputation Power: 68

A few similar examples of how to do this the easy way.

Code:

#!/usr/bin/env python

user = ''

while user != 'quit':
    user = raw_input('Pls input the nominated text: ')

Code:

#!/usr/bin/env python

user = raw_input('Pls input the nominated text: ')

while user != 'quit':
    user = raw_input('Pls input the nominated text: ')

Of course this exits if the user enters 'quit' but not hard to change to 'q'.

Mark.

__________________
programming language development: www.netytan.com – Hula

March 13th, 2004, 02:24 PM

MasterChief

Contributing User

Join Date: Feb 2003

Location: Canada

Posts: 543

Time spent in forums: 1 Day 11 h 18 m 34 sec
Reputation Power: 23

You should transform the text to be all upper-case letters or all lower-case letters. Then make the quit command 'q' and 'quit'.

So if a user puts in QuIt, it will be transformed into 'quit'.

comparing user input against a string (newbie)

Developer Shed Advertisers and Affiliates