How to replace text in a ruby string

Question

I am trying to write a very simple method in Ruby which takes a string and an array of words and checks if the string contains any of the words and if it does it replaces them w

Answer 1

You get this error because i doesn't start from 0 as you expected, in each method i is an element of array, and has string type, it's a first word from your sentence:

my_sentence_words = ["word"]
my_sentence_words.each do |i|
  puts i.length #=> 4
  puts i.type   #=> String
  puts i        #=> word
end

So you try to call my_sentence_words[word] instead of my_sentence_words[0]. You can try method each_index that passes index of element instead of element itself`:

def check(str, *arr)
  upstr = str.split(' ')
  upstr.eachindex do |i|       #=> i is index
    arr.each_index do  |j|  
      upstr[i].upcase! if upstr[i] == arr[j]        
    end
  end
  upstr
end

check("This is my sentence", "day", "is", "goal", "may", "my")
#=>["This", "IS", "MY", "sentence"]