struct Regex::MatchData
Overview
Regex::MatchData is the type of the special variable $~, and is the type
returned by Regex#match and String#match. It encapsulates all the
results of a regular expression match.
if md = "Crystal".match(/[p-s]/)
md.string # => "Crystal"
md[0] # => "r"
md[1]? # => nil
endMany Regex::MatchData methods deal with capture groups, and accept an integer
argument to select the desired capture group. Capture groups are numbered
starting from 1, so that 0 can be used to refer to the entire regular
expression without needing to capture it explicitly.
Defined in:
regex/match_data.crInstance Method Summary
- #==(other : Regex::MatchData)
-
#[](group_name : String)
Returns the match of the capture group named by group_name, or raises an
KeyErrorif there is no such named capture group. -
#[](n)
Returns the match of the nth capture group, or raises an
IndexErrorif there is no nth capture group. -
#[]?(group_name : String)
Returns the match of the capture group named by group_name, or
nilif there is no such named capture group. -
#[]?(n)
Returns the match of the nth capture group, or
nilif there isn't an nth capture group. -
#begin(n = 0)
Return the position of the first character of the nth match.
-
#byte_begin(n = 0)
Return the position of the first byte of the nth match.
-
#byte_end(n = 0)
Return the position of the next byte after the match.
-
#captures
Returns an array of unnamed capture groups.
- #clone
- #dup
-
#end(n = 0)
Return the position of the next character after the match.
-
#group_size : Int32
Returns the number of capture groups, including named capture groups.
- #inspect(io : IO)
-
#named_captures
Returns a hash of named capture groups.
-
#post_match
Returns the part of the original string after the match.
-
#pre_match
Returns the part of the original string before the match.
- #pretty_print(pp) : Nil
-
#regex : Regex
Returns the original regular expression.
-
#size
Returns the number of elements in this match object.
-
#string : String
Returns the original string.
-
#to_a
Convert this match data into an array.
-
#to_h
Convert this match data into a hash.
- #to_s(io : IO)
Instance methods inherited from struct Struct
==(other : self) : Bool
==,
hash : Int32
hash,
inspect(io : IO) : Nil
inspect,
pretty_print(pp) : Nil
pretty_print,
to_s(io)
to_s
Instance methods inherited from struct Value
==(other)
==,
dup
dup
Instance methods inherited from class Object
!=(other)
!=,
!~(other)
!~,
==(other)
==,
===(other : JSON::Any)===(other : YAML::Any)
===(other) ===, =~(other) =~, class class, dup dup, hash hash, inspect(io : IO)
inspect inspect, itself itself, not_nil! not_nil!, pretty_inspect(width = 79, newline = "\n", indent = 0) : String pretty_inspect, pretty_print(pp : PrettyPrint) : Nil pretty_print, tap(&block) tap, to_json(io : IO)
to_json to_json, to_pretty_json(indent : String = " ")
to_pretty_json(io : IO, indent : String = " ") to_pretty_json, to_s
to_s(io : IO) to_s, to_yaml(io : IO)
to_yaml to_yaml, try(&block) try, unsafe_as(type : T.class) forall T unsafe_as
Constructor methods inherited from class Object
from_json(string_or_io, root : String) : selffrom_json(string_or_io) : self from_json, from_yaml(string_or_io) : self from_yaml
Instance Method Detail
Returns the match of the capture group named by group_name, or
raises an KeyError if there is no such named capture group.
"Crystal".match(/r(?<ok>ys)/).not_nil!["ok"] # => "ys"
"Crystal".match(/r(?<ok>ys)/).not_nil!["ng"] # raises KeyErrorReturns the match of the nth capture group, or raises an IndexError
if there is no nth capture group.
"Crystal".match(/r(ys)/).not_nil![1] # => "ys"
"Crystal".match(/r(ys)/).not_nil![2] # raises IndexErrorReturns the match of the capture group named by group_name, or
nil if there is no such named capture group.
"Crystal".match(/r(?<ok>ys)/).not_nil!["ok"]? # => "ys"
"Crystal".match(/r(?<ok>ys)/).not_nil!["ng"]? # => nilReturns the match of the nth capture group, or nil if there isn't
an nth capture group.
When n is 0, returns the match for the entire Regex.
"Crystal".match(/r(ys)/).not_nil![0]? # => "rys"
"Crystal".match(/r(ys)/).not_nil![1]? # => "ys"
"Crystal".match(/r(ys)/).not_nil![2]? # => nilReturn the position of the first character of the nth match.
When n is 0 or not given, uses the match of the entire Regex.
Otherwise, uses the match of the nth capture group.
"Crystal".match(/r/).not_nil!.begin(0) # => 1
"Crystal".match(/r(ys)/).not_nil!.begin(1) # => 2
"クリスタル".match(/リ(ス)/).not_nil!.begin(0) # => 1Return the position of the first byte of the nth match.
When n is 0 or not given, uses the match of the entire Regex.
Otherwise, uses the match of the nth capture group.
"Crystal".match(/r/).not_nil!.byte_begin(0) # => 1
"Crystal".match(/r(ys)/).not_nil!.byte_begin(1) # => 2
"クリスタル".match(/リ(ス)/).not_nil!.byte_begin(0) # => 3Return the position of the next byte after the match.
When n is 0 or not given, uses the match of the entire Regex.
Otherwise, uses the match of the nth capture group.
"Crystal".match(/r/).not_nil!.byte_end(0) # => 2
"Crystal".match(/r(ys)/).not_nil!.byte_end(1) # => 4
"クリスタル".match(/リ(ス)/).not_nil!.byte_end(0) # => 9Returns an array of unnamed capture groups.
It is a difference from #to_a that the result array does not contain the match for the entire Regex (self[0]).
match = "Crystal".match(/(Cr)(?<name1>y)(st)(?<name2>al)/).not_nil!
match.captures # => ["Cr", "st"]
# When this regex has an optional group, result array may contain
# a `nil` if this group is not matched.
match = "Crystal".match(/(Cr)(stal)?/).not_nil!
match.captures # => ["Cr", nil]Return the position of the next character after the match.
When n is 0 or not given, uses the match of the entire Regex.
Otherwise, uses the match of the nth capture group.
"Crystal".match(/r/).not_nil!.end(0) # => 2
"Crystal".match(/r(ys)/).not_nil!.end(1) # => 4
"クリスタル".match(/リ(ス)/).not_nil!.end(0) # => 3Returns the number of capture groups, including named capture groups.
"Crystal".match(/[p-s]/).not_nil!.group_size # => 0
"Crystal".match(/r(ys)/).not_nil!.group_size # => 1
"Crystal".match(/r(ys)(?<ok>ta)/).not_nil!.group_size # => 2Returns a hash of named capture groups.
match = "Crystal".match(/(Cr)(?<name1>y)(st)(?<name2>al)/).not_nil!
match.named_captures # => {"name1" => "y", "name2" => "al"}
# When this regex has an optional group, result hash may contain
# a `nil` if this group is not matched.
match = "Crystal".match(/(?<name1>Cr)(?<name2>stal)?/).not_nil!
match.named_captures # => {"name1" => "Cr", "name2" => nil}Returns the part of the original string after the match. If the match ends at the end of the string, returns the empty string.
"Crystal".match(/yst/).not_nil!.post_match # => "al"Returns the part of the original string before the match. If the match starts at the start of the string, returns the empty string.
"Crystal".match(/yst/).not_nil!.pre_match # => "Cr"Returns the original regular expression.
"Crystal".match(/[p-s]/).not_nil!.regex # => /[p-s]/Returns the number of elements in this match object.
"Crystal".match(/[p-s]/).not_nil!.size # => 1
"Crystal".match(/r(ys)/).not_nil!.size # => 2
"Crystal".match(/r(ys)(?<ok>ta)/).not_nil!.size # => 3Returns the original string.
"Crystal".match(/[p-s]/).not_nil!.string # => "Crystal"Convert this match data into an array.
match = "Crystal".match(/(Cr)(?<name1>y)(st)(?<name2>al)/).not_nil!
match.to_a # => ["Crystal", "Cr", "y", "st", "al"]
# When this regex has an optional group, result array may contain
# a `nil` if this group is not matched.
match = "Crystal".match(/(Cr)(?<name1>stal)?/).not_nil!
match.to_a # => ["Cr", "Cr", nil]Convert this match data into a hash.
match = "Crystal".match(/(Cr)(?<name1>y)(st)(?<name2>al)/).not_nil!
match.to_h # => {0 => "Crystal", 1 => "Cr", "name1" => "y", 3 => "st", "name2" => "al"}
# When this regex has an optional group, result array may contain
# a `nil` if this group is not matched.
match = "Crystal".match(/(Cr)(?<name1>stal)?/).not_nil!
match.to_h # => {0 => "Cr", 1 => "Cr", "name1" => nil}