使用理解获取满足某些条件的列表元素

Question

I have a list like this:

foolist = ['foo   bar', 'foo', 'bar' 'foo bar']

I want the number of foo s in that list, without using regex. Is there a simpler way to do it than below, using one line?

print(len([i for i in [ 'foo' in line for line in foolist ] if i == True]))

The above is interesting, but it also makes my skin crawl in the way that nested ternary operators would.

Answer 1

This is a little shorter: use map to transform foolist to a list of 1's and 0', then sum them up:

sum(map(lambda x: 1 if 'foo' in x else 0, foolist))

Update: or even shorter:

len(tuple(filter(lambda x: 'foo' in x, foolist)))

My brain finds comprehensions incomprehensible when they are not simple so I move on to map/reduce/filter functions:)

UPDATE: Added tuple since in Python3, len can't count an iterator.