template< class OutputIt >
OutputIter format( OutputIt out,
const char_type* fmt_first, const char_type* fmt_last,
std::regex_constants::match_flag_type flags =
std::regex_constants::format_default ) const; | (1) | (since C++11) |
template< class OutputIt, class ST, class SA >
OutputIter format( OutputIt out,
const basic_string<char_type,ST,SA>& fmt,
std::regex_constants::match_flag_type flags =
std::regex_constants::format_default ) const; | (2) | (since C++11) |
template< class ST, class SA >
std::basic_string<char_type,ST,SA>
format( const std::basic_string<char_type,ST,SA>& fmt,
std::regex_constants::match_flag_type flags =
std::regex_constants::format_default ) const; | (3) | (since C++11) |
string_type format( const char_type* fmt_s,
std::regex_constants::match_flag_type flags =
std::regex_constants::format_default ) const; | (4) | (since C++11) |
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 OutputIterator. | ||
Return value
1-2)
out 3-4) The newly constructed string containing resulting character sequence.
Exceptions
(none).
Example
#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]
See also
| (C++11) | replaces occurrences of a regular expression with formatted replacement text (function template) |
| (C++11) | options specific to matching (typedef) |
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