Deadly Regular Expressions

#!/usr/bin/env ruby -w

Name = "Gray, James"

!!(Name =~ /\AGray/)      # => true
Name.start_with?("Gray")  # => true

!!(Name =~ /James\z/)    # => true
Name.end_with?("James")  # => true

!!(Name =~ /Dana/)     # => false
Name.include?("Dana")  # => false

!!(Name =~ /\A\z/)  # => false
Name.empty?         # => false

!!(Name =~ /\AGray, James\z/)  # => true
Name == "Gray, James"          # => true

!!(Name =~ /\A(?:Gray, James|Gray, Dana)\z/)  # => true
["Gray, James", "Gray, Dana"].include?(Name)  # => true

Name =~ /\A\w+/ && $&  # => "Gray"
Name[/\A\w+/]          # => "Gray"

Name =~ /\A(\w+),\s*(\w+)\z/ && $2  # => "James"
Name[/\A(\w+),\s*(\w+)\z/, 2]       # => "James"

Name =~ /\A(?<last>\w+),\s*(?<first>\w+)\z/ && $~[:first]  # => "James"
Name[/\A(?<last>\w+),\s*(?<first>\w+)\z/, :first]          # => "James"

Name.scan(/^.*\n?/)  # => ["Gray, James"]
Name.lines           # => ["Gray, James"]

Name.scan(/./m)  # => ["G", "r", "a", "y", ",", " ", "J", "a", "m", "e", "s"]
Name.chars       # => ["G", "r", "a", "y", ",", " ", "J", "a", "m", "e", "s"]

Name.gsub(/[aeiou]/, "")  # => "Gry, Jms"
Name.delete("aeiou")      # => "Gry, Jms"

Name.gsub(/[aeiou]/, "X") # => "GrXy, JXmXs"
Name.tr("aeiou", "X")     # => "GrXy, JXmXs"

# For the destructive operations that follow you can drop the `dup()` and
# switch `sub()` to `sub!()`, as long as you don't care about the return value.

Name.sub(/(?=,)/, " II")                 # => "Gray II, James"
Name.dup.insert(Name.index(","), " II")  # => "Gray II, James"

Name.sub(/\A/, "Name:  ")    # => "Name:  Gray, James"
Name.dup.prepend("Name:  ")  # => "Name:  Gray, James"

Name.sub(/\A.*\z/m, "Gray, Dana")  # => "Gray, Dana"
Name.dup.replace("Gray, Dana")     # => "Gray, Dana"

Name.sub(/\A.*\z/m, "")  # => ""
Name.dup.clear           # => ""



Spacey = "\tsome    space\r\n"

Spacey.sub(/\A\s+/, "")  # => "some    space\r\n"
Spacey.lstrip            # => "some    space\r\n"

Spacey.sub(/\s+\z/, "")  # => "\tsome    space"
Spacey.rstrip            # => "\tsome    space"

Spacey.sub(/\A\s*(.+?)\s*\z/m, '\1')  # => "some    space"
Spacey.strip                          # => "some    space"

Spacey.sub(/(?:\r?\n|\r)\z/m, "")  # => "\tsome    space"
Spacey.chomp                       # => "\tsome    space"

Spacey.sub(/(?:\r\n|.)\z/m, "")  # => "\tsome    space"
Spacey.chop                      # => "\tsome    space"

Spacey.gsub(/ +/, " ")  # => "\tsome space\r\n"
Spacey.squeeze(" ")     # => "\tsome space\r\n"