Ruby noob. Trying to build a hangman game and use the following code to find the index so I can replace the dashes with the guessed letter when a players guesses correctly. The words are from a json database. @letter and @word are added here as an example, and instance variables are used because I'm def methods in the full code.

Any ideas why this is not working? Can 'find_index' return multiple values for every place it finds the letter? If 'find_index' doesn't return multiple values is there an array method which does?

@word = "elephant"
@letter = "e"
@word = @word.split
@index = @word.find_index(@letter)
puts "the index is #{@index}"

CodePudding user response：

It seems you want indices for all characters in @word for @letter. If this is the case, then the following should work:

@word.chars.each_with_index.select { |c, i| c == @letter }.map(&:last)

Breaking this down...

• #chars returns an array of the characters in the word
• #each_with_index returns an Enumerator that yields the character and the iteration index
• #select is used to filter the array to character:index pairs, where the character matches @letter
• #map receives iterates the filtered array of character:index pairs and returns the last element for each pair (i.e. the index).

CodePudding user response：

You can use delimiter in split(), so you can split word into substrings based on it and return an array of these substrings. "elephant".split(//)

Then, having the index, you can call this index on the array word[0] and get the desired letter.

word = "elephant"
letter = "e"
word = word.split(//) # => ["e", "l", "e", "p", "h", "a", "n", "t"]
index = word.find_index(letter) # => 0
puts "the index of letter #{letter} is #{index}" #>> the index of letter e is 0
# or
puts "the letter at index 0 is #{word[0]}"  #>> letter at index 0 is e

Can 'find_index' return multiple values for every place it finds the letter?

No, it returns the index of the first object in array for which the block returns true. Here about find_index()

If 'find_index' doesn't return multiple values is there an array method which does?

You can try find_all() with block:

indices = (0 ... word.length).find_all { |i| word[i] == letter } # => [0, 2]