Question

I have arrays like this:

myArr = [a,b,c,d,e,f,g]
myArr = [a]
myArr = [a,b,c]

How can I break up the arrays such that:

Variable first_portion has the first 3 items and rest_portion has all remaining ones?

If an array has 3 or less items, I’d like rest_portion to contain nil so that I can check for it in logic.

Any advise?

Answer 1

You can use a range for the array index to accomplish this easily:

first_portion = myArr[0..2]
rest_portion = myArr[3..-1]

If the range partially overlaps the range, you’ll get an array with only as many items as are available. If the range has no overlap with the array, you’ll get nil.

[a,b,c,d,e,f,g][0..2]
#=> [a, b, c]
[a,b,c,d,e,f,g][3..-1]
#=> [d,e,f,g]

[a][0..2]
#=> [a]
[a][3..-1]
#=> nil