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rubystringcountsequenceenumerable

Ruby Counting chars in a sequence not using regex

Need help with this code on counting chars in a sequence.

This is what I want:

word("aaabbcbbaaa") == [["a", 3], ["b", 2], ["c", 1], ["b", 2], ["a", 3]]
word("aaaaaaaaaa") == [["a", 10]]
word("") == []

Here is my code:

def word(str)
words=str.split("")
count = Hash.new(0)

words.map {|char| count[char] +=1 }

return count
end

I got word("aaabbcbbaaa") => [["a", 6], ["b", 4], ["c", 1]], which is not what I want. I want to count each sequence. I prefer a none regex solution. Thanks.

Solution

  • Split string by chars, then group chunks by char, then count chars in chunks:

    def word str
  str
  .chars
  .chunk{ |e| e }
  .map{|(e,ar)| [e, ar.length] }
end

p word "aaabbcbbaaa"
p word("aaaaaaaaaa")
p word ""

    Result:

    [["a", 3], ["b", 2], ["c", 1], ["b", 2], ["a", 3]]
[["a", 10]]
[]