CODEWITHSUNDEEP
erlang
erlang
erlang

Reputation: 273

How to get a tuple in a list?

I would like to know how can I use lists:filter to get a specific tuple from a list of tuples. My code is :

myFilter(Item,List)->
         MyItems = lists:map(fun(X)-> element(2,X) end,List),
         lists:filter(fun()-> lists:member(Item,MyItems) end , List).

Example : 

myFilter(1,[{atom1,1,"P1"},{atom2,2,"P1"},{atom3,3,"P3"}]) = {atom1,1,"P1"}

Upvotes: 1

Views: 100

Answers (1)

Dogbert
Dogbert

Reputation: 222040

lists:keyfind is meant for exactly this! lists:keyfind(1, 2, List) will return the first tuple in the list whose 2nd item is 1, or return false if it doesn't find any:

1> List = [{atom1,1,"P1"},{atom2,2,"P1"},{atom3,3,"P3"}].
[{atom1,1,"P1"},{atom2,2,"P1"},{atom3,3,"P3"}]
2> lists:keyfind(1, 2, List).
{atom1,1,"P1"}

Upvotes: 4

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