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Difference between revisions of "cpp/regex/sub match"

From cppreference.com
< cpp‎ | regex
m (Use since= and until= params of {{ddcl}} template.)
m (Minor tweak.)
 
(6 intermediate revisions by 5 users not shown)
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{{cpp/title|sub_match}}
 
{{cpp/title|sub_match}}
 
{{cpp/regex/sub_match/navbar}}
 
{{cpp/regex/sub_match/navbar}}
{{ddcl | header=regex | since=c++11 | 1=
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{{ddcl|header=regex|since=c++11|
template<
+
template< class BidirIt >
    class BidirIt
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class sub_match;
> class sub_match;
+
 
}}
 
}}
  
The class template {{tt|sub_match}} is used by the regular expression engine to denote sequences of characters matched by marked sub-expressions.
+
The class template {{tt|std::sub_match}} is used by the regular expression engine to denote sequences of characters matched by marked sub-expressions.
A match is a {{tt|[begin, end)}} pair within the target range matched by the regular expression, but with additional observer functions to enhance code clarity.
+
A match is a {{range|begin|end}} pair within the target range matched by the regular expression, but with additional observer functions to enhance code clarity.
  
Only the default constructor is publicly accessible. Instances of {{tt|sub_match}} are normally constructed and populated as a part of a {{lc|std::match_results}} container during the processing of one of the regex algorithms.
+
Only the default constructor is publicly accessible. Instances of {{tt|std::sub_match}} are normally constructed and populated as a part of a {{lc|std::match_results}} container during the processing of one of the regex algorithms.
  
The member functions return defined default values unless the {{c|matched}} member is {{tt|true}}.
+
The member functions return defined default values unless the {{c|matched}} member is {{c|true}}.
  
{{tt|sub_match}} inherits from {{c|std::pair<BidirIt, BidirIt>}}, although it cannot be treated as a {{lc|std::pair}} object because member functions such as swap and assignment will not work as expected.
+
{{tt|std::sub_match}} inherits from {{c/core|std::pair<BidirIt, BidirIt>}}, although it cannot be treated as a {{lc|std::pair}} object because member functions such as assignment will not work as expected.
  
 
===Type requirements===
 
===Type requirements===
 
{{par begin}}
 
{{par begin}}
{{par req concept | BidirIt | BidirectionalIterator}}
+
{{par req named|BidirIt|BidirectionalIterator}}
 
{{par end}}
 
{{par end}}
  
Line 25: Line 24:
  
 
{{dsc begin}}
 
{{dsc begin}}
{{dsc header | regex}}
+
{{dsc header|regex}}
{{dsc hitem | Type | Definition}}
+
{{dsc hitem|Type|Definition}}
{{dsc | {{tt|csub_match}} | {{c|sub_match<const char*>}}}}
+
{{dsc|{{tt|std::csub_match}}|{{c/core|std::sub_match<const char*>}}}}
{{dsc | {{tt|wcsub_match}} | {{c|sub_match<const wchar_t*>}}}}
+
{{dsc|{{tt|std::wcsub_match}}|{{c/core|std::sub_match<const wchar_t*>}}}}
{{dsc | {{tt|ssub_match}} | {{c|sub_match<std::string::const_iterator>}}}}
+
{{dsc|{{tt|std::ssub_match}}|{{c/core|std::sub_match<std::string::const_iterator>}}}}
{{dsc | {{tt|wssub_match}} | {{c|sub_match<std::wstring::const_iterator>}}}}
+
{{dsc|{{tt|std::wssub_match}}|{{c/core|std::sub_match<std::wstring::const_iterator>}}}}
 
{{dsc end}}
 
{{dsc end}}
  
===Member types===
+
===Nested types===
 
{{dsc begin}}
 
{{dsc begin}}
{{dsc hitem | Member type | Definition}}
+
{{dsc hitem|Type|Definition}}
{{dsc | {{tt|iterator}} | {{c|BidirIt}}}}
+
{{dsc|{{tt|iterator}}|{{tt|BidirIt}}}}
{{dsc | {{tt|value_type}} | {{c|std::iterator_traits<BidirIt>::value_type}}}}
+
{{dsc|{{tt|value_type}}|{{c/core|std::iterator_traits<BidirIt>::value_type}}}}
{{dsc | {{tt|difference_type}} | {{c|std::iterator_traits<BidirIt>::difference_type}}}}
+
{{dsc|{{tt|difference_type}}|{{c/core|std::iterator_traits<BidirIt>::difference_type}}}}
{{dsc | {{tt|string_type}} | {{c|std::basic_string<value_type>}}}}
+
{{dsc|{{tt|string_type}}|{{c/core|std::basic_string<value_type>}}}}
 
{{dsc end}}
 
{{dsc end}}
  
===Member objects===
+
===Data members===
 
{{dsc begin}}
 
{{dsc begin}}
{{dsc| {{tt|matched}} | Indicates if this match was successful.}}
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{{dsc hitem|Member|Description}}
 +
{{dsc|{{dsc small|{{c/core|bool}}}} {{tt|matched}}|whether this match was successful}}
 
{{dsc end}}
 
{{dsc end}}
{{inherited | [[cpp/utility/pair | {{small|std::}}pair]] |
+
 
 +
{{inherited|[[cpp/utility/pair|{{small|std::}}pair]]|
 
{{dsc begin}}
 
{{dsc begin}}
{{dsc| {{tt|first}} | Start of the match sequence.}}
+
{{dsc mem obj|nolink=true|{{dsc small|BidirIt}} first|Start of the match sequence.}}
{{dsc| {{tt|second}} | One-past-the-end of the match sequence.}}
+
{{dsc mem obj|nolink=true|{{dsc small|BidirIt}} second|One-past-the-end of the match sequence.}}
 
{{dsc end}}
 
{{dsc end}}
 
}}
 
}}
  
 
===Member functions===
 
===Member functions===
 +
{{todo|Apply LWG 3204, add the swap() member function}}
 
{{dsc begin}}
 
{{dsc begin}}
{{dsc inc | cpp/regex/sub_match/dsc constructor}}
+
{{dsc inc|cpp/regex/sub_match/dsc constructor}}
  
{{dsc h2 | Observers}}
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{{dsc h2|Observers}}
{{dsc inc | cpp/regex/sub_match/dsc length}}
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{{dsc inc|cpp/regex/sub_match/dsc length}}
{{dsc inc | cpp/regex/sub_match/dsc str}}
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{{dsc inc|cpp/regex/sub_match/dsc str}}
{{dsc inc | cpp/regex/sub_match/dsc compare}}
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{{dsc inc|cpp/regex/sub_match/dsc compare}}
 
{{dsc end}}
 
{{dsc end}}
  
 
===Non-member functions===
 
===Non-member functions===
 
{{dsc begin}}
 
{{dsc begin}}
{{dsc inc | cpp/regex/sub_match/dsc operator_cmp}}
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{{dsc inc|cpp/regex/sub_match/dsc operator_cmp}}
{{dsc tfun | cpp/regex/sub_match/operator_ltlt | title=operator<< | outputs the matched character subsequence}}
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{{dsc inc|cpp/regex/sub_match/dsc operator_ltlt}}
 
{{dsc end}}
 
{{dsc end}}
  
 
===See also===
 
===See also===
 
{{dsc begin}}
 
{{dsc begin}}
{{dsc tclass | cpp/regex/regex_token_iterator | iterates through regex submatches | notes={{mark c++11}}}}
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{{dsc inc|cpp/regex/dsc regex_token_iterator}}
 
{{dsc end}}
 
{{dsc end}}
  
[[de:cpp/regex/sub match]]
+
{{langlinks|de|es|fr|it|ja|pt|ru|zh}}
[[es:cpp/regex/sub match]]
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[[fr:cpp/regex/sub match]]
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[[it:cpp/regex/sub match]]
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[[ja:cpp/regex/sub match]]
+
[[pt:cpp/regex/sub match]]
+
[[ru:cpp/regex/sub match]]
+
[[zh:cpp/regex/sub match]]
+

Latest revision as of 01:04, 14 November 2024

Defined in header <regex>
template< class BidirIt >
class sub_match;
(since C++11)

The class template std::sub_match is used by the regular expression engine to denote sequences of characters matched by marked sub-expressions. A match is a [beginend) pair within the target range matched by the regular expression, but with additional observer functions to enhance code clarity.

Only the default constructor is publicly accessible. Instances of std::sub_match are normally constructed and populated as a part of a std::match_results container during the processing of one of the regex algorithms.

The member functions return defined default values unless the matched member is true.

std::sub_match inherits from std::pair<BidirIt, BidirIt>, although it cannot be treated as a std::pair object because member functions such as assignment will not work as expected.

Contents

[edit] Type requirements

-
BidirIt must meet the requirements of LegacyBidirectionalIterator.

[edit] Specializations

Several specializations for common character sequence types are provided:

Defined in header <regex>
Type Definition
std::csub_match std::sub_match<const char*>
std::wcsub_match std::sub_match<const wchar_t*>
std::ssub_match std::sub_match<std::string::const_iterator>
std::wssub_match std::sub_match<std::wstring::const_iterator>

[edit] Nested types

Type Definition
iterator BidirIt
value_type std::iterator_traits<BidirIt>::value_type
difference_type std::iterator_traits<BidirIt>::difference_type
string_type std::basic_string<value_type>

[edit] Data members

Member Description
bool matched whether this match was successful

Inherited from std::pair

BidirIt first
Start of the match sequence.
(public member object)
BidirIt second
One-past-the-end of the match sequence.
(public member object)

[edit] Member functions

constructs the match object
(public member function) [edit]
Observers
returns the length of the match (if any)
(public member function) [edit]
converts to the underlying string type
(public member function) [edit]
compares matched subsequence (if any)
(public member function) [edit]

[edit] Non-member functions

(removed in C++20)(removed in C++20)(removed in C++20)(removed in C++20)(removed in C++20)(C++20)
compares a sub_match with another sub_match, a string, or a character
(function template) [edit]
outputs the matched character subsequence
(function template) [edit]

[edit] See also

iterates through the specified sub-expressions within all regex matches in a given string or through unmatched substrings
(class template) [edit]