ios - Performance with a lot of string operations comparing objective C and swift -

i have lot of string operations concatenating, replacing , finding indexes of large texts (10000 characters) ...

the operations slow. same doing in java/android faster.

i asking if same in objective c faster.

i ios newby , know swift far (so cant try simply), thats why asking if objective c swift-bridging faster ?

update have lot of substring operations in loop (also replace), concatenates new string. newtext & stext of type string, stext has 10000 characters, loop have 100 iterations:

newtext=newtext + stext.substring(istart,endindex: iend);   func substring(startindex: int, endindex: int) -> string {     //println("substring" + self);     var start = advance(self.startindex, startindex)     var end = advance(self.startindex, endindex)     return self.substringwithrange(range<string.index>(start: start, end: end)) } 

update 2 performance test (replace string) string, nsstring, cfstring

from information provided (thanks lot), seems not difference between objective-c , swift. more stringtype use. made performance test types: string, nsstring , cfstring

 func performance_test_with_strings(){           var stextnsstring:nsstring="<1000 character> searchstring end";          var stextstring=string(stextnsstring);         //var stextcfstring:cfmustring=stextnsstring cfstring;         var storeplace="searchstring";           var stextcfstring:cfmutablestringref=cfstringcreatemutable(nil, 0);         cfstringappend(stextcfstring, stextstring as! cfmutablestringref);         var storeplacecfstring="searchstring" cfstring;         var storeplacecfstring2="mynewstring" cfstring;         var chrono1:chronometer=chronometer();         chrono1.start();            var i=0;i<10000;i++ {             var newtext=stextnsstring.stringbyreplacingoccurrencesofstring(storeplace, withstring: "mynewstring");         }         chrono1.zwischenstand("after replacing nsstring");          var i=0;i<10000;i++ {             var newtext=stextstring.stringbyreplacingoccurrencesofstring(storeplace, withstring: "mynewstring");         }         chrono1.zwischenstand("after replacing string");         //cfshow(cfmutablestring);           var i=0;i<5000;i++ {             // compare correct i'll have 2 replacments in loop of 5000 iterations               specialreplace(&stextcfstring,swhat: "searchstring",sto: "mynewstring");             specialreplace(&stextcfstring,swhat: "mynewstring",sto: "searchstring");          }         chrono1.zwischenstand("after replacing cfstring");         chrono1.showmeasures();         exit(0);     }      func specialreplace(inout stext:cfmutablestringref,swhat:string, sto:string){          var cfrange = cfstringfind(stext, swhat cfstring, nil);         cfstringreplace(stext, cfrange, sto cfstring);      }       class chronometer: nsobject {       var mearures:[(string,double)]=[(string,double)]();     var starttime = nsdate();   // <<<<<<<<<<   end time     var lasttime:double=0;      func start(){         starttime = nsdate();   // <<<<<<<<<<   end time      }     func zwischenstand(mytext:string){         var zwischenzeit = nsdate();         let timeinterval: double = zwischenzeit.timeintervalsincedate(starttime);         let actualtimeconsumed=timeinterval-lasttime;         mearures.append((mytext,actualtimeconsumed));         var textshow=mytext + " actual : " + string(stringinterpolationsegment: actualtimeconsumed);         textshow=textshow + " total :" + string(stringinterpolationsegment: timeinterval);         println(textshow);         lasttime=timeinterval;     }      func showmeasures(){         var total:double=0;         var i=0 ; < mearures.count ; i++ {             let text=mearures[i].0;             let measure=mearures[i].1;             println(text + " : " + string(stringinterpolationsegment: measure));             total = total + measure;         }         println("total : " + string(stringinterpolationsegment: total));     }  } 

after replacing nsstring actual : 1.15460801124573 total :1.15460801124573

after replacing string actual : 1.15148597955704 total :2.30609399080276

after replacing cfstring actual : 0.323610007762909 total :2.62970399856567

after replacing nsstring : 1.15460801124573

after replacing string : 1.15148597955704

after replacing cfstring : 0.323610007762909

total : 2.62970399856567

so conclusion case best use cfstring.

is test correct ?

one thing note swift attempts unicode handling properly. java , cocoa's nsstring not this. both assume string encoded in utf-16 , each character takes 1 16 bit integer. therefore string handling works called basic multilingual plane

with nsstring , in java, finding nth "character" easy, index nth item in array, second part of surrogate pair. can't tell if nth character except scanning previous characters make sure none of them 2 word characters.

swift properly, @ expense of lot of linear (aka slow) scanning through strings.