How To Split A String Into Consecutive Substrings Of Length At Most 3 In All Possible Ways?

27 July 2011 - 1 answer

I am trying to take a string, between length 1 and 10, and output all possible ways of breaking up the string into consecutive substrings that are of sizes 1, 2, or 3. For example:

Input: 123456

Slice the integer into individual characters, then proceed through to find combinations. The code would return all of the following arrays.

[1, 2, 3, 4, 5, 6]
[12, 3, 4, 5, 6]
[1, 23, 4, 5, 6]
[1, 2, 34, 5, 6]
[1, 2, 3, 45, 6]
[1, 2, 3, 4, 56]
[12, 34, 5, 6]
[12, 3, 45, 6]
[12, 3, 4, 56]
[1, 23, 45, 6]
[1, 2, 34, 56]
[1, 23, 4, 56]
[12, 34, 56]
[123, 4, 5, 6]
[1, 234, 5, 6]
[1, 2, 345, 6]
[1, 2, 3, 456]
[123, 456]
[1, 23, 456]
[1, 234, 56]
[12, 345, 6]
[12, 3, 456]
[123, 4, 56]
[123, 45, 6]

I'm trying to do this in ruby. Thanks!

Here's a working function. May be not optimal as I didn't spend much time on it.

str = "1234567890"

def f(s, n)
return [[]] if s.empty?

(1..[n, s.length].min).map{|c| f(s[c..-1], n).map{|a| [s[0, c]] + a}}.inject(&:+)
end

puts f(str, 3).collect{|l| l * "\t"}

EDIT: Made it a bit shorter and the length is now passed as second parameter to function for flexibility.