std::match_results<BidirIt,Alloc>::format (3) - Linux Manuals

std::match_results<BidirIt,Alloc>::format: std::match_results<BidirIt,Alloc>::format

NAME

std::match_results<BidirIt,Alloc>::format - std::match_results<BidirIt,Alloc>::format

Synopsis

template< class OutputIt >
OutputIter format( OutputIt out,
const char_type* fmt_first, const char_type* fmt_last, (1) (since C++11)
std::regex_constants::match_flag_type flags =
std::regex_constants::format_default ) const;
template< class OutputIt, class ST, class SA >
OutputIter format( OutputIt out,
const basic_string<char_type,ST,SA>& fmt, (2) (since C++11)
std::regex_constants::match_flag_type flags =
std::regex_constants::format_default ) const;
template< class ST, class SA >
std::basic_string<char_type,ST,SA>
format( const std::basic_string<char_type,ST,SA>& fmt, (3) (since C++11)
std::regex_constants::match_flag_type flags =
std::regex_constants::format_default ) const;
string_type format( const char_type* fmt_s,
std::regex_constants::match_flag_type flags = (4) (since C++11)
std::regex_constants::format_default ) const;

format outputs a format string, replacing any format specifiers or escape sequences in that string with match data from *this.
1) The format character sequence is defined by the range [fmt_first, fmt_last). The resulting character sequence is copied to out.
2) The format character sequence is defined by the characters in fmt. The resulting character sequence is copied to out.
3-4) The format character sequence is defined by the characters in fmt and fmt_s respectively. The resulting character sequence is copied to a newly constructed std::basic_string, which is returned.
The flags bitmask determines which format specifiers and escape sequences are recognized.
The behavior of format is undefined if ready() != true.

Parameters

fmt_begin, fmt_end - pointers to a range of characters defining the format character sequence
fmt - std::basic_string defining the format character sequence
fmt_s - pointer to a null-terminated character string defining the format character sequence
out - iterator that the resulting character sequence is copied to
flags - std::regex_constants::match_flag_type bitmask specifying which format specifiers and escape sequences are recognized

Type requirements

-
OutputIt must meet the requirements of LegacyOutputIterator.

Return value

1-2) out
3-4) The newly constructed string containing resulting character sequence.

Exceptions

(none)

Example

// Run this code

  #include <iostream>
  #include <string>
  #include <regex>

  int main()
  {
      std::string s = "for a good time, call 867-5309";
      std::regex phone_regex("\\d{3}-\\d{4}");
      std::smatch phone_match;

      if (std::regex_search(s, phone_match, phone_regex)) {
          std::string fmt_s = phone_match.format(
              "$`" // $` means characters before the match
              "[$&]" // $& means the matched characters
              "$'"); // $' means characters following the match
          std::cout << fmt_s << '\n';
      }
  }

Output:

  for a good time, call [867-5309]