I have the following array.
@arr = ["Ac,Ab,Aa", "Ba,Bb,Bd", "Ca,Cc,Cb", "Dd,Da,Dc", "aA,aC,aD", "bD,bA,bB", "cB,cA,cC", "dD,dC,dA"]
Now I want to extract the first two letters of each item.
@firsttwo = ["Ac", "Ba", "Ca", "Dd", "aA", "bD", "cB", "dD"]
How can I achieve this in Ruby.
I tried this but it didn't work.
@firsttwo = @combi.select{ |item| item[0, 1]}
You need to use Array#map :
@arr = ["Ac,Ab,Aa", "Ba,Bb,Bd", "Ca,Cc,Cb", "Dd,Da,Dc", "aA,aC,aD", "bD,bA,bB", "cB,cA,cC", "dD,dC,dA"]
@arr.map { |item| item[0..1] }
# => ["Ac", "Ba", "Ca", "Dd", "aA", "bD", "cB", "dD"]
#select selects the element from receiver, if block returns true. Now in your case item[0..1] giving a string object in each iteration, which has truthy value, thus #select selects all element from the receiver.
Try this:
@firsttwo = @arr.map { |item| item.split(",")[0] }
You are currently using select. This returns a collection where each iteration returns true. You seem to want to preform the same operation on each member of the collection without doing any testing. .map is suited for this.
