获取ruby中所有字符的索引

Question

I am trying to get the index of string which has duplicate characters. But if I have same characters it keeps returning the index of first occurrence of that character

    str = "sssaadd"

    str.each_char do |char|
       puts "index: #{str.index(char)}"
    end

Output:-
index: 0
index: 0
index: 0
index: 3
index: 3
index: 5
index: 5

Answer 1

Use Enumerator#with_index :

str = "sssaadd"
str.each_char.with_index do |char, index|
  puts "#{index}: #{char}"
end

Answer 2

If you want to find all indices of duplicated substrings, you can use this:

'sssaadd'.enum_for(:scan, /(.)\1/).map do |match| 
  [Regexp.last_match.begin(0), match.first]  
end
# => [[0, "s"], [3, "a"], [5, "d"]]

Here we scan all the string by regex, that finds duplicated characters. The trick is that block form of scan doesn't return any result, so in order to make it return block result we convert scan to enumerator and add a map after that to get required results.

See also: ruby regex: match and get position(s) of

Answer 3

You also use this

  str = "sssaadd"

  arr=str.split('')

  arr.each_with_index do|char,index|
     puts "index : #{index}"
  end