Question

i recently wrote a method to cycle through /usr/share/dict/words and return a list of palindromes using my ispalindrome(x) method
here’s some of the code…what’s wrong with it? it just stalls for 10 minutes and then returns a list of all the words in the file

def reverse(a):
    return a[::-1]

def ispalindrome(a):
    b = reverse(a)
    if b.lower() == a.lower():
        return True
    else:
        return False

wl = open('/usr/share/dict/words', 'r')
wordlist = wl.readlines()
wl.close()
for x in wordlist:
    if not ispalindrome(x):
        wordlist.remove(x)
print wordlist

Answer 1

wordlist = wl.readlines()

When you do this, there is a new line character at the end, so your list is like:

['eye\n','bye\n', 'cyc\n']

the elements of which are obviously not a palindrome.

You need this:

['eye','bye', 'cyc']

So strip the newline character and it should be fine.

To do this in one line:

wordlist = [line.strip() for line in open('/usr/share/dict/words')]

EDIT: Iterating over a list and modifying it is causing problems. Use a list comprehension,as pointed out by Matthew.