Ruby regex for a split every four characters not working

Question

I'm trying to split a sizeable string every four characters. This is how I'm trying to do it:

big_string.split(/..../)

This is yielding a nil array. As far as I can see, this should be working. It even does when I plug it into an online ruby regex test.

Answer 1

Hmm, I don't know what Rubular is doing there and why - but

big_string.split(\....\)

does translate into

split the string at every 4-character-sequence

which should correctly result into something like

["", "", "", "abc"]

Answer 2

Try scan instead:

$ irb
>> "abcd1234beefcake".scan(/..../)
=> ["abcd", "1234", "beef", "cake"]

or

>> "abcd1234beefcake".scan(/.{4}/)
=> ["abcd", "1234", "beef", "cake"]

If the number of characters isn't divisible by 4, you can also grab the remaining characters:

>> "abcd1234beefcakexyz".scan(/.{1,4}/)
=> ["abcd", "1234", "beef", "cake", "xyz"]

(The {1,4} will greedily grab between 1 and 4 characters)

Answer 3

Whoops.

str = 'asdfasdfasdf'
c = 0; out = []; inum = 4
(str.length/inum).round.times do |s|
out.push(str[c,round(s*inum)])
c += inum
end