iOS Development--string segmentation, stitching

---------------------A string split instance---------------------
NSString * ptr = @ "I am a Man";


Return a string as a whole as a split condition to a nsarray non-variable group
Nsarray * array = [ptr componentsseparatedbystring:@ ""];


If modified, convert Nsarray to Nsmutablearray
Nsmutablearray * array1 = [Nsmutablearray Arraywitharray:array];


To split a character in a string as a segmentation condition
Nsarray * array2 = [ptr componentsseparatedbycharactersinset:[nscharacterset charactersetwithcharactersinstring:@ "," ]];

"Character Set"
Nscharacterset This is a character set.


Converts a string into a character set
[Nscharacterset charactersetwithcharactersinstring:@ ","]


---------------------string Concatenation instance---------------------
NSString * str = [array componentsjoinedbystring:@ ""];
If the split condition appears at the beginning or the end, an empty string @ "" will appear, and if not, it will need to be converted to nsmutablestring to process the empty string.
FUNC1: [Array1 removeobject:@ ""];
Find empty string to delete directly
Func2:for (id obj in array1) {
if ([obj length] = = 0)
The length of the empty string is 0
if ([obj isequaltostring:@ ""])
Compare to empty string (string is not = = comparison, use function)
}

In OC, there are 3 ways to say,

NSString *str=[nsstring    initwithformat:@ "%@,%@", a  , b]; NSString *str=[a   stringbyappendingstring:b]; NSString *str=[string   stringbyappendingformat:@ "%@,%@",  a  ,  b];

iOS Development--string segmentation, stitching