regex.rb

# Phone regex with if/else

phone_number = "+44 76 4775 4789"

if phone_number.match?(/^\+\d{2}\s\d{2}\s\d{4}\s\d{4}$/)
  puts "This is a valid UK international phone number"
else
  puts "It's not valid!"
end

# Better phone regex allowing for optional spaces

if phone_number.match?(/^\+\d{2}\s*\d{2}\s*\d{4}\s*\d{4}$/)
  puts "This is a valid UK international phone number"
else
  puts "It's not valid!"
end

# Simple regex with ternary operator

input = "hi my name is lenny"

puts input =~ /is/ ? "hello" : "goodbye"

# Multi line regex with the multi-line modifier

text = "try this is a multi-line text line
to match only this
try and not the others"

# End and beginning of line match
puts text =~ /^try .* line$/m

# End and beginning of entire string match
puts text =~ /\Atry .* line\z/m

# Multiple group regex

match_data = "John Doe Watkins".match(/^(\w+) (\w+) (\w+)$/)

p match_data
puts match_data[0]
puts "#{match_data[1]}"
puts "#{match_data[2]}"
puts "#{match_data[3]}"

# Multiple named group regex

pattern = /^(?<first_name>\w+) (?<last_name>\w+)$/

match_data = "John Doe".match(pattern)
p match_data
puts match_data[:first_name]
puts match_data[:last_name]

# Gsub with a regex

puts "hello guys".gsub("hello", "goodbye")
puts "hello guys".gsub(/g\w{3}/, 'le wagon')
puts "hello g&%$".gsub(/g.{3}/, 'le wagon')

puts "hello guys".gsub(/^(\w+) (\w+)$/, 'Oh \2, \1!')
puts "hello guys yay".gsub(/^(\w+) (\w+) (\w+)$/, 'Oh \1, \2 hey\3!')

# Destructive gsub with a regex

string = "hello guys yay"
puts string
puts string.gsub!(/^(\w+) (\w+) (\w+)$/, 'Oh \1, \2 hey\3!')
puts string

# Original scan to return an array of matches

p "Let's play tic tac toe".scan(/t../)

# Improved scan to return of individual words

p "Let's play tic tac toe".scan(/\bt..\b/)