Finding Index of a word in an array

Question

I am new to ruby and recently started reading the Seven languages in Seven Weeks

and at the page 35, there is practice question on

For the string “Hello, Ruby,” find the index of the word “Ruby.”

How do it in Ruby? Need some guidance ..

Answer 1

from the docs:

index(regexp [, offset]) → fixnum or nil Returns the index of the first occurrence of the given substring or pattern (regexp) in str. Returns nil if not found. If the second parameter is present, it specifies the position in the string to begin the search.

"hello".index('e')             #=> 1
"hello".index('lo')            #=> 3
"hello".index('a')             #=> nil
"hello".index(ee)              #=> 1
"hello".index(/[aeiou]/, -3)   #=> 4

so for your predicament:

ruby-1.9.3-p194@heroku macbook-5:$ irb
s="1.9.3p194 :001 > s="hello, ruby,"
 => "hello, ruby," 
1.9.3p194 :002 > s.index("ruby")
 => 7 

Answer 2

.index

"Hello, Ruby,".index("Ruby")