for loop nested inside the expression from an if statement

Question

This is a question about syntax more than anything. I am pretty sure that I am almost right, but not quite. I'm trying to put a for loop inside of the expression for an if statement.

A mock-up of what I think it should be for a simple palindrome tester:

toTest = "asdffdsa"
if toTest[i]==toTest[-i] for i in range(len(toTest)/2):
    print("It's a palendrome!")

Thanks in advance for your help!

I did look through that, however there isn't an example of what I'm looking for. — Mokolodi1, Feb 21 '12 at 02:12

Sven Marnach · Accepted Answer · 2012-02-21T02:29:08.503

7

I guess you mean

if all(toTest[i] == toTest[-i] for i in range(len(toTest)/2)):
    print("It's a palindrome!")

Note that it would be much easier to do

if toTest == toTest[::-1]:
    print("It's a palindrome!")

edited Feb 21 '12 at 02:29

answered Feb 21 '12 at 02:11

Sven Marnach

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Thanks! You just answered my question AND taught me a new keyword. Does the "-1" in "toTest[::-1]" reverse the list? – Mokolodi1 Feb 21 '12 at 02:15
1

@Mokolodi1: Yes, it reverses the string, see http://stackoverflow.com/a/3705676/279627. – Sven Marnach Feb 21 '12 at 02:17
Not a keyword; `all` is a function. – Karl Knechtel Feb 21 '12 at 03:40

score 1 · Answer 2 · answered Feb 21 '12 at 02:13

1

While it may not be exactly what you're looking for, here is a short-hand to check if a string is a palindrome in Python:

toTest = "asdffdsa"
if toTest == toTest[::-1]: print ("It's a palindrome!")

answered Feb 21 '12 at 02:13

mau5padd

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10

for loop nested inside the expression from an if statement

2 Answers2