Grep a string in an array using two inputs

Question

I need to search over an array to find out which objects contain a specific string. The method must take two inputs.

This is a one-input method that works, and returns all objects with the letter t:

def my_array_finding_method(source)
  source.grep(/t/)
end

my_array_finding_method(array)

This does not work:

def my_array_finding_method(source, thing_to_find)
  source.grep(/thing_to_find/)
end

my_array_finding_method(array, "t")

I must modify the second bit of code to work. How can I do so?

ndnenkov · Accepted Answer · 2015-09-18 22:56:13Z

2

You have to interpolate the variable name. Otherwise, it is just interpreted as plain text.

source.grep(/#{thing_to_find}/)

answered Sep 18, 2015 at 22:56

ndnenkov

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1 Comment

jnicholea Over a year ago

Thank you! This is exactly what I needed, and will be very helpful in the future. As this is my first question, and a very basic one, I'm sure it's clear that I'm really new to Ruby/coding.

Cary Swoveland · Accepted Answer · 2015-09-19 06:46:59Z

0

You don't have to use a regular expression:

def my_array_finding_method(source, thing_to_find)
  source.select { |s| s.include?(thing_to_find) }
end

arr = %w| It's true that cats have nine lives. |
   #=> ["It's", "true", "that", "cats", "have", "nine", "lives."] 
my_array_finding_method(array, "t")
   #=> ["It's", "true", "that", "cats"]

answered Sep 19, 2015 at 6:46

Cary Swoveland

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