I can't figure out why the following expression does not convert Strings to Integers:
[["1", "2"], ["10", "20"]].each {|sr| sr.map(&:to_i)}
=> [["1", "2"], ["10", "20"]]
So, instead of getting a nested array of integer numbers I'm still getting the same String values. Any idea ?
Thank you.
uSer Ruby version: 2.6.1
It's because you're using each, which returns original array. Use map instead:
[["1", "2"], ["10", "20"]].map { |sr| sr.map(&:to_i) }
# => [[1, 2], [10, 20]]
You can also use map!, which modifies an array instead of returning a new one, like this:
[["1", "2"], ["10", "20"]].each { |sr| sr.map!(&:to_i) }
# => [[1, 2], [10, 20]]
It depends on what you want, obviously.
each returns as well as to the difference if using the bang ! version of map in the block.While the answer by @MarekLipka perfectly sheds a light on the issue in pure ruby, I am here to shamelessly promote my gem iteraptor:
[["1", "2"], ["10", "20"]].
iteraptor.
map { |_key, value| value.to_i }
#⇒ [[1, 2], [10, 20]]
or, if you like Spanish:
[["1", "2"], ["10", "20"]].mapa { |_, value| value.to_i }
#⇒ [[1, 2], [10, 20]]
It would work with arrays of any depth:
[[["1", "2"], ["3"]], [[[[["10"]]]], "20"]].
mapa { |_key, value| value.to_i }
#⇒ [[[1, 2], [3]], [[[[[10]]]], 20]]
λ) throughout your code baseUse this code
p [["1", "2"], ["10", "20"]].map{|x,y|[x.to_i,y.to_i]}
Output
[[1, 2], [10, 20]]
If you change it to [["1", "2"], ["10", "20"]].map { |sr| sr.map(&:to_i) } you'll get the integer values.
