std::regex_replace
Defined in header <regex> | ||
template<class OutputIt, class BidirIt, class Traits, class CharT, class STraits, class SAlloc > | (1) | (since C++11) |
template<class OutputIt, class BidirIt, class Traits, class CharT > OutputIt regex_replace( OutputIt out, BidirIt first, BidirIt last, | (2) | (since C++11) |
template<class Traits, class CharT, class STraits, class SAlloc, class FTraits, class FAlloc > | (3) | (since C++11) |
template<class Traits, class CharT, class STraits, class SAlloc > std::basic_string<CharT, STraits, SAlloc> | (4) | (since C++11) |
template<class Traits, class CharT, class STraits, class SAlloc > std::basic_string<CharT> | (5) | (since C++11) |
template<class Traits, class CharT > std::basic_string<CharT> | (6) | (since C++11) |
regex_replace uses the regular expression re to perform substitution on the target character sequence:
[first, last) to out, replacing any sequences that match re with characters formatted by fmt. Equivalent to: using iter_type =std::regex_iterator<BidirIt, CharT, Traits>; iter_type seq_begin(first, last, re, flags), seq_end; using result_type =std::match_results<BidirIt>; result_type m; bool need_to_copy =(flags &std::regex_constants::format_no_copy)==0;bool format_all =(flags &std::regex_constants::format_first_only)!=0; for(iter_type i = seq_begin; i != seq.end();++i){ m =*i;if(need_to_copy) out =std::copy(m.prefix().first, m.prefix().second, out);if(format_all || i == seq_begin) out =/* replace-expr */} if(need_to_copy) out = m.ready()?std::copy(m.suffix().first, m.suffix().second, out):std::copy(first, last, out); return out;
regex_replace(std::back_inserter(result),
str.begin(), str.end(), re, fmt, flags);
return result;.
regex_replace(std::back_inserter(result),
s, s +std::char_traits<CharT>::length(s), re, fmt, flags);
return result;.
Contents |
[edit]Parameters
| first, last | - | the target character range |
| str | - | the target std::string |
| s | - | the target null-terminated C-style string |
| re | - | the regular expression |
| fmt | - | the regex replacement format string, exact syntax depends on the value of flags |
| flags | - | flags used to determine how the match will be performed |
| out | - | output iterator to store the result of the replacement |
[edit]Return value
As described above.
[edit]Exceptions
May throw std::regex_error to indicate an error condition.
[edit]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 resultsstd::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
[edit]Defect reports
The following behavior-changing defect reports were applied retroactively to previously published C++ standards.
| DR | Applied to | Behavior as published | Correct behavior |
|---|---|---|---|
| LWG 2213 | C++11 | out was not updated by the replacements | out is updated |
[edit]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) |
| replaces specified portion of a string (public member function of std::basic_string<CharT,Traits,Allocator>) |
