substrings

[Ed Redman]

I am struggling with the following.
Given a sting of a given length example string = 'bkerhcno'
give all the subsets of string of length 4

I don't need all the permutations just the subsets.
I can use the slice method to give me some subsets i.e
s1 = string.slice(0,4)
s2 = string.slice(1,4) etc.
Just how do I generate all the possible combination of 4 characters.

By analagy, would like to extend to finding all combination of length 5,6,
and 7.

Hope someone can help.

 

[Robert Klemme]

I am struggling with the following.
Given a sting of a given length example string = 'bkerhcno'
give all the subsets of string of length 4

I don't need all the permutations just the subsets.
I can use the slice method to give me some subsets i.e
s1 = string.slice(0,4)
s2 = string.slice(1,4) etc.
Just how do I generate all the possible combination of 4 characters.

By analagy, would like to extend to finding all combination of length
5,6, and 7.

Hope someone can help.

def sub_strings(s,len)
(s.length - len).times do |idx|
yield s[idx,len]
end
end
"bker"
"kerh"
"erhc"
"rhcn"
"hcno"
=> 0..4

Kind regards

robert