Managing user input's case in Python

Question

I have set up a script to say something when the user enters something other than Yes. However it still says this when the user says Yes. What am I doing wrong?

I am using Python 2.7.2.
Here is my code:

print 'Hi! Welcome!'
begin = raw_input ('Will you answer some questions for me? ')
if begin == 'yes':
    print 'Ok! Let\'s get started then!'
else:
    print 'Well then why did you open a script clearly entiled\'QUIZ\'?!'

You should use double quotes so you don't have to escape the quotation mark eg. `print "Ok! Let's get started then!"` — jamylak, Apr 08 '12 at 11:50

Abhijit · Answer 1 · 2012-04-08T11:52:12.703

6

Just change the line

if begin == 'yes':

to

if begin.lower() == 'yes':

Because string compare is case sensitive, the match will only if true iff user enters the reply in lower case

edited Apr 08 '12 at 11:52

answered Apr 08 '12 at 11:46

Abhijit

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@Lattyware: Do you see the difference in the posted time? – Abhijit Apr 08 '12 at 11:48
SO normally warns me when an answer has been posted as I am writing mine, so I presumed you would have seen that warning. – Gareth Latty Apr 08 '12 at 11:48
@Lattyware: Your first post was the first three lines. If you disagree now, its difficult to prove :-) – Abhijit Apr 08 '12 at 11:49
1

Ah, this is true - I do the whole post then edit in the links and formatting bit too much now to think about it. My apologies. – Gareth Latty Apr 08 '12 at 11:51
Guys, it's not "difficult to prove": If you're not sure who was first in the future, you can check the edit history by clicking on the modification time, e.g., `edited 2 hours ago` – alexis Apr 08 '12 at 13:58
@alexis Actually, it is. I edited mine within the grace period of 5 minutes (IIRC), so it doesn't get added as another edit. – Gareth Latty Apr 08 '12 at 22:49
Oops, sorry. Hadn't realized that. – alexis Apr 09 '12 at 09:58

score 5 · Answer 2 · edited Oct 24 '17 at 12:19

The issue here is case sensitivity.

>>> "yes" == "Yes"
False

Try using str.lower() on the user input before your comparison to ignore case. E.g:

print 'Hi! Welcome!'
begin = raw_input ('Will you answer some questions for me? ')
if begin.lower() == 'yes':
    print 'Ok! Let\'s get started then!'
else:
    print "Well then why did you open a script clearly entiled\'QUIZ\'?!"

#If a single apostrophe is used inside the print str then it must be surrounded by double apostrophes.

score 0 · Answer 3 · answered Aug 05 '13 at 19:12

Abhijit's method also works if you just want to accept more than one version of a string from a user. For example, I'm using this to confirm whether the user wants to exit:

confirm = input('Are you sure you would like to exit? N to re-run program')
  if confirm.lower() in ('n','no'): #.lower just forces the users input to be changed to lower case
    print("I'll take that as a no.")
    return confirm #this then just goes back to main()
  else:
    exit()

This way either 'n' or 'N'; 'no' or 'NO' or 'nO' are all accepted cases of 'no'.

Managing user input's case in Python

3 Answers3