gistfile1.rb

moby = <<EOL
Call me Ishmael. Some years ago - never mind how long precisely - having little
or no money in my purse, and nothing particular to interest me on shore, I
thought I would sail about a little and see the watery part of the world.
[Moby Dick - 1st paragraph]
EOL

#
# "."  - matches any character
# "\s" - matches digits (0-9)
# "\S" - matches non-digits
# "\s" - matches white-space  (space, newline, tabs)
# "\S" - matches non-white-space !(space, newline, tabs)
# "\S" - matches non-word characters !(a-z, 0-9, _)
# "\w" - matches word characters (a-z, 0-9, _)
# "\W" - matches non-word characters !(a-z, 0-9, _)
#
/./ =~ moby  # 0
/\s/ =~ moby # 4
/\S/ =~ moby # 0
/\w/ =~ moby # 0
/\W/ =~ moby # 4
/\d/ =~ moby # 242
/\D/ =~ moby # 0

#
# [aeiou] - sets, match first occurrence of any
# [a-h]   - range, match first occurrence of a,b,c...h
#
/[abc]/ =~ moby # 1
/[F-T]/ =~ moby # 8

#
# Negate search
# [^pattern]
#
/[^\D]/ =~ moby # 242
/[^[A-C]]/ =~ moby # 1

#
#  Either side of the '=~' will work
#
moby =~ /[Cc]all/   # 0
moby =~ /Call/ 	    # 0
moby =~ /call/ 	    # nil

/[Cc]all/ =~ moby     # 0
/Call/ 	  =~ moby     # 0
/call/ 	  =~ moby     # nil

# beginnings
# ^ matches beginning of string, or line within string
# \A matches beginning of string
#
/^Call/ =~   moby # 0
/^or/ =~     moby # 80
/\ACall/ =~  moby # 0
/\Aor/ =~    moby # nil

# endings
# $ matches beginning of string, or line within string
# \Z matches beginning of string
#
/little$/ =~       moby # 73
/paragraph\]$/ =~   moby # 246
/little\Z/ =~      moby # nil
/paragraph\]\Z/ =~  moby # 246

# regex modifiers
# i - case insensitive
# m - multiline
/ishmael/i       =~ moby # 8
/little.*money/m =~ moby #73  # if


#
#  Passively store your match the old way: "$1"
#
/(never.*)long/ =~ moby
$1 # "never mind how"

#
#  Store your answer the cool, hip way
#  Actively store your match the cool, hip way:
#  (?<VAR_NAME>pattern)
#
/(?<never_str>never.*)long/ =~ moby
never_str # "never mind how"