<regex> functions - Microsoft Docs

regex_match, Tests whether a regular expression matches the entire ... Example. C++. Copy. // std__regex__regex_match.cpp // compile with: ... Skiptomaincontent Thisbrowserisnolongersupported. UpgradetoMicrosoftEdgetotakeadvantageofthelatestfeatures,securityupdates,andtechnicalsupport. DownloadMicrosoftEdge Moreinfo Tableofcontents Exitfocusmode Language ReadinEnglish Save Tableofcontents ReadinEnglish Save Feedback Edit Twitter LinkedIn Facebook Email Tableofcontents functions Article 02/08/2022 8minutestoread 6contributors Inthisarticle Name Description regex_match Testswhetheraregularexpressionmatchestheentiretargetstring. regex_replace Replacesmatchedregularexpressions. regex_search Searchesforaregularexpressionmatch. swap Swapstwobasic_regexormatch_resultsobjects. regex_match Testswhetheraregularexpressionmatchestheentiretargetstring. //(1) template boolregex_match( BidItfirst, Biditlast, match_results&match, constbasic_regex&re, match_flag_typeflags=match_default); //(2) template boolregex_match( BidItfirst, Biditlast, constbasic_regex&re, match_flag_typeflags=match_default); //(3) template boolregex_match( constElem*ptr, match_results&match, constbasic_regex&re, match_flag_typeflags=match_default); //(4) template boolregex_match( constElem*ptr, constbasic_regex&re, match_flag_typeflags=match_default); //(5) template boolregex_match( constbasic_string&str, match_results::const_iterator,Alloc>&match, constbasic_regex&re, match_flag_typeflags=match_default); //(6) template boolregex_match( constbasic_string&str, constbasic_regex&re, match_flag_typeflags=match_default); Parameters BidIt Theiteratortypeforsubmatches.Forcommoncasesthisoneofstring::const_iterator,wstring::const_iterator,constchar*orconstwchar_t*. Alloc Thematchresultsallocatorclass. Elem Thetypeofelementstomatch.Forcommoncasesthisisstring,wstring,char*orwchar_t*. RXtraits Traitsclassforelements. Alloc2 Theregularexpressionallocatorclass. IOtraits Thestringtraitsclass. IOalloc Thestringallocatorclass. flags Flagsformatches. first Beginningofsequencetomatch. last Endofsequencetomatch. match Thematchresults.CorrespondstoElemtype:smatchforstring,wsmatchforwstring,cmatchforchar*orwcmatchforwchar_t*. ptr Pointertobeginningofsequencetomatch.Ifptrischar*,thenusecmatchandregex.Ifptriswchar_t*thenusewcmatchandwregex. re Theregularexpressiontomatch.Typeregexforstringandchar*,orwregexforwstringandwchar_t*. str Stringtomatch.CorrespondstothetypeofElem. Remarks Eachtemplatefunctionreturnstrueonlyiftheentireoperandsequencestrexactlymatchestheregularexpressionargumentre.Useregex_searchtomatchasubstringwithinatargetsequenceandregex_iteratortofindmultiplematches.Thefunctionsthattakeamatch_resultsobjectsetitsmemberstoreflectwhetherthematchsucceededandifsowhatthevariouscapturegroupsintheregularexpressioncaptured. Thefunctionsthattakeamatch_resultsobjectsetitsmemberstoreflectwhetherthematchsucceededandifsowhatthevariouscapturegroupsintheregularexpressioncaptured. Example //std__regex__regex_match.cpp //compilewith:/EHsc #include #include usingnamespacestd; intmain() { //(1)withchar* //Notehowconstchar*requirescmatchandregex constchar*first="abc"; constchar*last=first+strlen(first); cmatchnarrowMatch; regexrx("a(b)c"); boolfound=regex_match(first,last,narrowMatch,rx); if(found) wcout< OutItregex_replace( OutItout, BidItfirst, BidItlast, constbasic_regex&re, constbasic_string&fmt, match_flag_typeflags=match_default); template basic_stringregex_replace( constbasic_string&str, constbasic_regex&re, constbasic_string&fmt, match_flag_typeflags=match_default); Parameters OutIt Theiteratortypeforreplacements. BidIt Theiteratortypeforsubmatches. RXtraits Traitsclassforelements. Alloc Theregularexpressionallocatorclass. Elem Thetypeofelementstomatch. flags Flagsformatches. first Beginningofsequencetomatch. fmt Theformatforreplacements. last Endofsequencetomatch. out Theoutputiterator. re Theregularexpressiontomatch. str Stringtomatch. Remarks Thefirstfunctionconstructsaregex_iteratorClassobjectiter(first,last,re,flags)andusesittosplititsinputrange[first,last)intoaseriesofsubsequencesT0M0T1M1...TN-1MN-1TN,whereMnisthenthmatchdetectedbytheiterator.Ifnomatchesarefound,T0istheentireinputrangeandNiszero.If(flags&format_first_only)!=0onlythefirstmatchisused,T1isalloftheinputtextthatfollowsthematch,andNis1.Foreachiintherange[0,N),if(flags&format_no_copy)==0itcopiesthetextintherangeTitotheiteratorout.Itthencallsm.format(out,fmt,flags),wheremisthematch_resultsobjectreturnedbytheiteratorobjectiterforthesubsequenceMi.Finally,if(flags&format_no_copy)==0itcopiesthetextintherangeTNtotheiteratorout.Thefunctionreturnsout. Thesecondfunctionconstructsalocalvariableresultoftypebasic_stringandcallsregex_replace(back_inserter(result),str.begin(),str.end(),re,fmt,flags).Itreturnsresult. Example //std__regex__regex_replace.cpp //compilewith:/EHsc #include #include intmain() { charbuf[20]; constchar*first="axayaz"; constchar*last=first+strlen(first); std::regexrx("a"); std::stringfmt("A"); std::regex_constants::match_flag_typefonly= std::regex_constants::format_first_only; *std::regex_replace(&buf[0],first,last,rx,fmt)='\0'; std::cout< boolregex_search( BidItfirst, Biditlast, match_results&match, constbasic_regex&re, match_flag_typeflags=match_default); template boolregex_search( BidItfirst, Biditlast, constbasic_regex&re, match_flag_typeflags=match_default); template boolregex_search( constElem*ptr, match_results&match, constbasic_regex&re, match_flag_typeflags=match_default); template boolregex_search( constElem*ptr, constbasic_regex&re, match_flag_typeflags=match_default); template boolregex_search( constbasic_string&str, match_results::const_iterator,Alloc>&match, constbasic_regex&re, match_flag_typeflags=match_default); template boolregex_search( constbasic_string&str, constbasic_regex&re, match_flag_typeflags=match_default); Parameters BidIt Theiteratortypeforsubmatches. Alloc Thematchresultsallocatorclass. Elem Thetypeofelementstomatch. RXtraits Traitsclassforelements. Alloc2 Theregularexpressionallocatorclass. IOtraits Thestringtraitsclass. IOalloc Thestringallocatorclass. flags Flagsformatches. first Beginningofsequencetomatch. last Endofsequencetomatch. match Thematchresults. ptr Pointertobeginningofsequencetomatch. re Theregularexpressiontomatch. str Stringtomatch. Remarks Eachtemplatefunctionreturnstrueonlyifasearchforitsregularexpressionargumentreinitsoperandsequencesucceeds.Thefunctionsthattakeamatch_resultsobjectsetitsmemberstoreflectwhetherthesearchsucceededandifsowhatthevariouscapturegroupsintheregularexpressioncaptured. Example //std__regex__regex_search.cpp //compilewith:/EHsc #include #include intmain() { constchar*first="abcd"; constchar*last=first+strlen(first); std::cmatchmr; std::regexrx("abc"); std::regex_constants::match_flag_typefl= std::regex_constants::match_default; std::cout<mr2; std::cout< voidswap( basic_regex&left, basic_regex&right)noexcept; template voidswap( match_results&left, match_results&right)noexcept; Parameters Elem Thetypeofelementstomatch. RXtraits Traitsclassforelements. Remarks Thetemplatefunctionsswapthecontentsoftheirrespectiveargumentsinconstanttimeanddon'tthrowexceptions. Example //std__regex__swap.cpp //compilewith:/EHsc #include #include intmain() { std::regexrx0("c(a*)|(b)"); std::regexrx1; std::cmatchmr0; std::cmatchmr1; swap(rx0,rx1); std::regex_search("xcaaay",mr1,rx1); swap(mr0,mr1); std::csub_matchsub=mr0[1]; std::cout< regex_constantsClass regex_errorClass regex_iteratorClass operators regex_token_iteratorClass regex_traitsClass typedefs Feedback Submitandviewfeedbackfor Thisproduct Thispage Viewallpagefeedback Inthisarticle