std::regex_replace
| Defined in header <regex>
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| template< class OutputIt, class BidirIt, class Traits, class CharT, |
(1) | (since C++11) |
| template< class OutputIt, class BidirIt, class Traits, class CharT > |
(2) | (since C++11) |
| template< class Traits, class CharT, class STraits, class SAlloc, |
(3) | (since C++11) |
| template< class Traits, class CharT, class STraits, class SAlloc > |
(4) | (since C++11) |
| template< class Traits, class CharT, class STraits, class SAlloc > |
(5) | (since C++11) |
| template< class Traits, class CharT > std::basic_string<CharT> |
(6) | (since C++11) |
regex_replace uses a regular expression to perform substitution on a sequence of characters:
[first, last) to out, replacing any sequences that match re with characters formatted by fmt. In other words:- Constructs a std::regex_iterator object
ias if by std::regex_iterator<BidirIt, CharT, traits> i(first, last, re, flags), and uses it to step through every match of re within the sequence[first,last). - For each such match
m, copies the non-matched subsequence (m.prefix()) into out as if by out = std::copy(m.prefix().first, m.prefix().second, out) and then replaces the matched subsequence with the formatted replacement string as if by calling out = m.format(out, fmt, flags). - When no more matches are found, copies the remaining non-matched characters to out as if by out = std::copy(last_m.suffix().first, last_m.suffix().second, out) where
last_mis a copy of the last match found. - If there are no matches, copies the entire sequence into out as-is, by out = std::copy(first, last, out).
- If flags contains std::regex_constants::format_no_copy, the non-matched subsequences are not copied into out.
- If flags contains std::regex_constants::format_first_only, only the first match is replaced.
- Constructs a std::regex_iterator object
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).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).Contents |
[edit] 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 |
| fmt | - | the regex replacement format string, exact syntax depends on the value of flags
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| flags | - | the match flags of type std::regex_constants::match_flag_type |
| out | - | output iterator to store the result of the replacement |
| Type requirements | ||
-OutputIt must meet the requirements of LegacyOutputIterator.
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-BidirIt must meet the requirements of LegacyBidirectionalIterator.
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[edit] Return value
result which contains the output.[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 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
[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>)
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