Ruby Hangman - how to find the index of a matching letter in an array

Question

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}"

Ask yourself how _you_ know where the occurrences of e in elephant are. Now express that same procedure in Ruby. — matt, Mar 26 '22 at 23:22
Does this solve your problem? [Return index of all occurrences of a character in a string in ruby](https://stackoverflow.com/q/1819540/477037) — Stefan, Mar 27 '22 at 15:53
Based on @matt 's comment though I worked on some other approaches and settled on using scan without converting the string with this https://stackoverflow.com/questions/3520208/get-index-of-string-scan-results-in-ruby to find the index — Siobhan Vida Ashmole, Mar 29 '22 at 14:35

Tim Lowrimore · Accepted Answer · 2022-03-29T15:50:38.180

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 iterates over the filtered array of character:index pairs and returns the last element for each pair (i.e. the index).

Ruby Hangman - how to find the index of a matching letter in an array

1 Answers1