Find element in list

Question

I have a list like

list_a = [(1, 2), (2, 3), (4, 5)]

and now using this list i wanted to find a element which has last value 3 any short method to achieve this? it should return (2,3)

related: [Python: find first element in a sequence that matches a predicate](http://stackoverflow.com/questions/8534256/python-find-first-element-in-a-sequence-that-matches-a-predicate) — jfs, Feb 14 '13 at 10:16

score 9 · Accepted Answer · answered Feb 14 '13 at 09:58

9

For example:

In [1]: list_a = [(1, 2), (2, 3), (4, 5)]

In [2]: next(x for x in list_a if x[1] == 3)
Out[2]: (2, 3)

Note that it returns a single element, not a list of them (seems to be what you are asking). If there are multiple tuples, the first one is returned.

answered Feb 14 '13 at 09:58

Lev Levitsky

Use `next((...), None)` so that it doesn't raise an exception when the values run out. – Volatility Feb 14 '13 at 10:00
@Volatility Thanks for the comment. I'll leave it for the OP to decide; having an exception in this case may be also a good idea. – Lev Levitsky Feb 14 '13 at 10:01

cms_mgr · Answer 2 · 2013-02-14T11:11:19.110

0

for item in list_a:
    if item[-1] == 3:
        return item

Or, if you might want to return multiple values:

return_list = []
for item in list_a:
    if item[-1] == 3:
        return_list.append(item)
return return_list

edited Feb 14 '13 at 11:11

answered Feb 14 '13 at 09:57

cms_mgr

1

You might wanna use non-capitalized `for`. – Feb 14 '13 at 10:00
Ha! Hadn't seen that, thanks. The list comprehension answers are way better anyway. – cms_mgr Feb 14 '13 at 11:11

score 0 · Answer 3 · answered Feb 14 '13 at 09:59

0

something simple like

for x in list_a: 
    if x[1] == 3: print x

answered Feb 14 '13 at 09:59

Aditya Sihag

3 Answers3