Stiati de ele? Eu abia acum am aflat, dar cu siguranta am sa le folosesc. http://www.globalnerdy.com/2012/09/23/objective-c-nsnumber-nsarray-nsdictionary-less-yak-shaving/

Da stiam din sesiunile video wwdc “Modern Objective C”.
Pe langa literals foarte folositor mi se pare array/dictionary subscripting.
http://clang.llvm.org/docs/ObjectiveCLiterals.html
Ce au uitat sa introduca e o alternativa la stringWithFormat:

tare as vrea sa vad o concatenare de stringuri cu +uri in loc de stringByAppendingString, poate mai adauga cateva la wwdc-ul asta.

Pana acum n-am folosit niciodata mutableCopy, pt string am folosit NSMutableString stringWithString, dar m-am inspirat din articol si am avut niste surprize

2013-05-01 10:47:16.563 SpeedTests[1876:907] creation of 1000000 mutablestrings in 5.857117   2013-05-01 07:47:07 +0000 2013-05-01 07:47:13 +0000
2013-05-01 10:47:16.580 SpeedTests[1876:907] creation of 1000000 strings with mutableCopy in 2.978280   2013-05-01 07:47:13 +0000 2013-05-01 07:47:16 +0000
2013-05-01 10:47:16.590 SpeedTests[1876:907] creation of 1000000 strings in 0.013725   2013-05-01 07:47:16 +0000 2013-05-01 07:47:16 +0000

NSMutableString stiu ca e foarte slow, nu prea folosesc si nu cred ca am avut nevoie undeva pana acum.