StackOverflow2013

Note that there are some explanatory texts on larger screens.

plurals

PORecursive Program: What am I doing wrong?
text
Body
copied!<p>I am trying to write a code that would analyze if a word is a palindrome. BTW a palindrome is a word that is read the same backward and forward. Example are "madam" or "noon"</p> <p>Here is a try:</p> <pre><code>x = raw_input("please enter a word:\n") L = len(x) # this part returns the first letter of the word def first(word): return word[0] # this part returns the last letter of the word def last(word): return word[-1] def middle(word): return word[1:-1] def is_palindrome(word): if L <= 2: print 'enter a word with at least three letters' elif first(word) != last(word): print 'This word is not a palindrome' else: word = middle(word) is_palindrome(word) is_palindrome(x) </code></pre> <p>But when executed, I get </p> <pre><code>IndexError: string index out of range ...line 7, in first return word[0] </code></pre> <p>The first branch of "is_palindrome" works perfectly. i.e. when the word is not a palindrome, I get no errors. Like "noopn" is executed with no errors, but the error is in the second branch</p> <p>I've playing with this code for so many times but can't figure out the "iterative part" I have the answer but I don't want to look at it yet. I need to figure out two things: 1. a way to make the iteration in the function is_palindrome work correctly? and 2. a way to exit the program in the end. </p> <p>Could you folks direct me to how to answer these questions without providing the solution yet?</p> <p>Finally where should I put the print statement: print 'This word is a palindrome'</p> <p>Thank you</p>

Querying!

Guidance

An individual column

Larger individual text columns get their own page to allow for proper reading.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload