This is part of the Semicolon&Sons Code Diary - consisting of lessons learned on the job. You're in the ruby category.
Last Updated: 2024-10-12
I had data akin to the following
triples = [[1, 2, 3], [4, 5, 6], [7, 8, 9]]
I wanted the 2nd element of each array, so I tried the following:
triples.first.map {|a,b,c| b}
This failed, in that b
was equal to nil. When I switched it to a
, it contained the entire triplet.
The error occurred because I switched type from an array of arrays, to a single
array by calling first
. Thus the code was mapping over the elements in the
array [1, 2, 3]
and therefore only had one variable to assign, a
.
The fix was to keep things as an array of arrays all the way
triples.first(2).map {|a,b,c| b}