Defined in header <regex> | ||
---|---|---|
template< class OutputIt, class BidirIt, class Traits, class CharT, class STraits, class SAlloc > OutputIt regex_replace( OutputIt out, BidirIt first, BidirIt last, const std::basic_regex<CharT,Traits>& re, const std::basic_string<CharT,STraits,SAlloc>& fmt, std::regex_constants::match_flag_type flags = std::regex_constants::match_default ); | (1) | (since C++11) |
template< class OutputIt, class BidirIt, class Traits, class CharT > OutputIt regex_replace( OutputIt out, BidirIt first, BidirIt last, const std::basic_regex<CharT,Traits>& re, const CharT* fmt, std::regex_constants::match_flag_type flags = std::regex_constants::match_default ); | (2) | (since C++11) |
template< class Traits, class CharT, class STraits, class SAlloc, class FTraits, class FAlloc > std::basic_string<CharT,STraits,SAlloc> regex_replace( const std::basic_string<CharT,STraits,SAlloc>& s, const std::basic_regex<CharT,Traits>& re, const std::basic_string<CharT,FTraits,FAlloc>& fmt, std::regex_constants::match_flag_type flags = std::regex_constants::match_default ); | (3) | (since C++11) |
template< class Traits, class CharT, class STraits, class SAlloc > std::basic_string<CharT,STraits,SAlloc> regex_replace( const std::basic_string<CharT,STraits,SAlloc>& s, const std::basic_regex<CharT,Traits>& re, const CharT* fmt, std::regex_constants::match_flag_type flags = std::regex_constants::match_default ); | (4) | (since C++11) |
template< class Traits, class CharT, class STraits, class SAlloc > std::basic_string<CharT> regex_replace( const CharT* s, const std::basic_regex<CharT,Traits>& re, const std::basic_string<CharT,STraits,SAlloc>& fmt, std::regex_constants::match_flag_type flags = std::regex_constants::match_default ); | (5) | (since C++11) |
template< class Traits, class CharT > std::basic_string<CharT> regex_replace( const CharT* s, const std::basic_regex<CharT,Traits>& re, const CharT* fmt, std::regex_constants::match_flag_type flags = std::regex_constants::match_default ); | (6) | (since C++11) |
regex_replace
uses a regular expression to perform substitution on a sequence of characters:
1) Copies characters in the range
[first,last)
to out
, replacing any sequences that match re
with characters formatted by fmt
. In other words:- Constructs a
std::regex_iterator
objecti
as if bystd::regex_iterator<BidirIt, CharT, traits> i(first, last, re, flags)
, and uses it to step through every match ofre
within the sequence[first,last)
. - For each such match
m
, copies the non-matched subsequence (m.prefix()
) intoout
as if byout = std::copy(m.prefix().first, m.prefix().second, out)
and then replaces the matched subsequence with the formatted replacement string as if by callingout = m.format(out, fmt, flags)
. - When no more matches are found, copies the remaining non-matched characters to
out
as if byout = std::copy(last_m.suffix().first, last_m.suffix().second, out)
wherelast_m
is a copy of the last match found. - If there are no matches, copies the entire sequence into
out
as-is, byout = std::copy(first, last, out)
- If
flags
containsstd::regex_constants::format_no_copy
, the non-matched subsequences are not copied intoout
. - If
flags
containsstd::regex_constants::format_first_only
, only the first match is replaced.
2) same as 1), but the formatted replacement is performed as if by calling
out = m.format(out, fmt, fmt + char_traits<charT>::length(fmt), flags)
3-4) Constructs an empty string
result
of type std::basic_string<CharT, ST, SA>
and calls std::regex_replace(std::back_inserter(result), s.begin(), s.end(), re, fmt, flags)
. 5-6) Constructs an empty string
result
of type std::basic_string<CharT>
and calls std::regex_replace(std::back_inserter(result), s, s + std::char_traits<CharT>::length(s), re, fmt, flags)
.Parameters
first, last | - | the input character sequence, represented as a pair of iterators |
s | - | the input character sequence, represented as std::basic_string or character array |
re | - | the std::basic_regex that will be matched against the input sequence |
flags | - | the match flags of type std::regex_constants::match_flag_type |
fmt | - | the regex replacement format string, exact syntax depends on the value of flags |
out | - | output iterator to store the result of the replacement |
Type requirements | ||
- OutputIt must meet the requirements of OutputIterator . | ||
- BidirIt must meet the requirements of BidirectionalIterator . |
Return value
1-2) Returns a copy of the output iterator
out
after all the insertions. 3-6) Returns the string
result
which contains the output.Exceptions
May throw std::regex_error
to indicate an error condition.
Example
#include <iostream> #include <iterator> #include <regex> #include <string> int main() { std::string text = "Quick brown fox"; std::regex vowel_re("a|e|i|o|u"); // write the results to an output iterator std::regex_replace(std::ostreambuf_iterator<char>(std::cout), text.begin(), text.end(), vowel_re, "*"); // construct a string holding the results std::cout << '\n' << std::regex_replace(text, vowel_re, "[$&]") << '\n'; }
Output:
Q**ck br*wn f*x Q[u][i]ck br[o]wn f[o]x
See also
(C++11) | attempts to match a regular expression to any part of a character sequence (function template) |
(C++11) | options specific to matching (typedef) |
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