String includes substrings from arrays - ruby

Question

I have the following:
input string = "1234"
output new_array should = [12, 3, 4, 34]

Answer 1

def string_to_array(string)
noun = ["d", "fgh", "i", "jk", "bcd", "cdef"]
verb = ["cd", "ef", "f", "jkl", "abc"]
ary = (noun+verb).select { |s| string.include? s }
ary.unshift(ary.delete(string)).compact
end
string = "cdef"
string_to_array(string) #=> ["cdef", "d", "cd", "ef", "f"]
I used Array#select, Array#+, Array#delete, Array#unshift, Array#compact and String#include?.
If you want to remove duplicate from output array, use Array#uniq

Answer 2

You could use String#scan (see the last sentence of the doc especially) together with a regular expression. My objective is to demonstrate this approach, not to suggest that it should be the preferred approach.
nouns = ["cdef", "d", "fgh", "i", "jk", "bcd"]
verbs = ["cd", "ef", "f", "jkl", "abc"]
R = Regexp.new (nouns+verbs).map { |s| "(?=(#{s}))?" }.join
#=> /(?=(cdef))?(?=(d))?(?=(fgh))?(?=(i))?(?=(jk))?(?=(bcd))?(?=(cd))?(?=(ef))?(?=(f))?(?=(jkl))?(?=(abc))?/
def string_to_array(str, nouns, strings)
str.scan(R).flatten.compact
end
str = "cdef"
string_to_array(str, nouns, verbs)
#=> ["cdef", "cd", "d", "ef", "f"]
Note:
str.scan(R)
#=> [["cdef", nil, nil, nil, nil, nil, "cd", nil, nil, nil, nil],
# [nil, "d", nil, nil, nil, nil, nil, nil, nil, nil, nil],
# [nil, nil, nil, nil, nil, nil, nil, "ef", nil, nil, nil],
# [nil, nil, nil, nil, nil, nil, nil, nil, "f", nil, nil],
# [nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil]]
(?=(cdef))? ((?=(cdef)?) also works) is a positive lookahead enclosed in a capture group. It requires that a particular location in the string is immediately followed by the content of the lookahead, but is not part of the match itself. The question mark makes the lookahead optional.