Length of longest word in a list

Question

What is the more pythonic way of getting the length of the longest word:

len(max(words, key=len))

Or:

max(len(w) for w in words)

Answer 1

Just for info using ipython %timeit

In [150]: words
Out[150]: ['now', 'is', 'the', 'winter', 'of', 'our', 'partyhat']

In [148]: %timeit max(len(w) for w in words)
100000 loops, best of 3: 1.87 us per loop

In [149]: %timeit len(max(words, key=len))
1000000 loops, best of 3: 1.35 us per loop

Just updated with more words to demonstrate @Omnifarious's point/comment.

In [160]: words = map(string.rstrip, open('/usr/share/dict/words').readlines())

In [161]: len(words)
Out[161]: 235886

In [162]: %timeit max(len(w) for w in words)
10 loops, best of 3: 44 ms per loop

In [163]: %timeit len(max(words, key=len))
10 loops, best of 3: 25 ms per loop