Merging two same values in python

Question

For example I have this lists of numbers / id's:

[1001, 1002, 1002, 1003, 1004]

how do I merge or make 1002 only one? So it would like this:

[1001, 1002,1003, 1004]

I know this pretty basic and I've been looking for a solution in Google for a while and all I see are how to merge dicts, which is not what I need. I just need to merge those same values.

Take a look at this too: http://stackoverflow.com/questions/12897374/get-unique-values-from-a-list-in-python — rafaelc, Apr 14 '15 at 09:19

score 5 · Answer 1 · edited Apr 14 '15 at 09:23

5

You can create set from list and convert it back to list:

>>> a = [1001, 1002, 1002, 1003, 1004]
>>> a = list(set(a))
>>> a
[1001, 1002, 1003, 1004]

In case the order matters and needs to be sorted (even though in this example the output looks ordered, the result is not guaranteed to be sorted when using set), use:

>>> sorted(set(a))

edited Apr 14 '15 at 09:23

Anshul Goyal

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answered Apr 14 '15 at 09:17

dizballanze

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@dizballance, my previous statement was not about the output being sorted yes or no, it was about maintaining the *same* order as the input. So for example `5 2 9 9 1` would return `5 2 9 1` and not `1 2 5 9`. – KillianDS Apr 14 '15 at 09:27

score 0 · Answer 2 · answered Apr 14 '15 at 09:19

0

If the order does not matter, you can use the set built-in function like so:

l = [1002, 1001, 1002, 1003, 1004]

list(set(l))

answered Apr 14 '15 at 09:19

ny6ab

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score 0 · Answer 3 · answered Apr 14 '15 at 09:32

0

Sets do not have duplicate values. You can take a list of numbers, convert it to a set, and convert it back to a list:

a = [1001, 1002, 1002, 1003, 1004]
b = list(set(a))

will result in 'b' having the value

[1001, 1002, 1003, 1004]

answered Apr 14 '15 at 09:32

Irving Moy

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Merging two same values in python

3 Answers3