Python list lookup with partial match

Question

For the following list:

test_list = ['one', 'two','threefour']

How would I find out if an item starts with 'three' or ends with 'four' ?

For example, instead of testing membership like this:

two in test_list

I want to test it like this:

startswith('three') in test_list.

How would I accomplish this?

Answer 1

You can use any():

any(s.startswith('three') for s in test_list)

Answer 2

You could use one of these:

>>> [e for e in test_list if e.startswith('three') or e.endswith('four')]
['threefour']
>>> any(e for e in test_list if e.startswith('three') or e.endswith('four'))
True

Answer 3

http://www.faqs.org/docs/diveintopython/regression_filter.html should help.

test_list = ['one', 'two','threefour']

def filtah(x):
  return x.startswith('three') or x.endswith('four')

newlist = filter(filtah, test_list)

Answer 4

If you're looking for a way to use that in a conditional you could to this:

if [s for s in test_list if s.startswith('three')]:
  # something here for when an element exists that starts with 'three'.

Be aware that this is an O(n) search - it won't short circuit if it finds a matching element as the first entry or anything along those lines.