Find an element in a list of tuples


I have a list 'a'

a= [(1,2),(1,4),(3,5),(5,7)]

I need to find all the tuples for a particular number. say for 1 it will be

result = [(1,2),(1,4)]

How do I do that?

8/25/2015 12:31:58 PM

Accepted Answer

If you just want the first number to match you can do it like this:

[item for item in a if item[0] == 1]

If you are just searching for tuples with 1 in them:

[item for item in a if 1 in item]
8/25/2015 12:25:55 PM

There is actually a clever way to do this that is useful for any list of tuples where the size of each tuple is 2: you can convert your list into a single dictionary.

For example,

test = [("hi", 1), ("there", 2)]
test = dict(test)
print test["hi"] # prints 1

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