objective-c數組的七種遍歷方法總結

//第一種

[arr enumerateObjectsUsingBlock: ^(id obj, NSUInteger idx, BOOL *stop){

     NSLog(@ "%ld,%@" ,idx,[arr objectAtIndex:idx]);

}];

//第二種

dispatch_apply([arr count], dispatch_get_global_queue( 0 , 0 ), ^(size_t index){ //並行

     NSLog(@ "%ld,%@" ,index,[arr objectAtIndex:index]);

});

//第三種

dispatch_apply([arr count], dispatch_get_main_queue(), ^(size_t index){ //串行，容易引發主線程堵塞，能夠另外開闢線程

     NSLog(@ "%ld,%@" ,index,[arr objectAtIndex:index]);

});

//第四種

for (NSString*str in arr) {

      NSLog(@ "%@" ,str);

}

//第五種，do-while

int i = 0 ;

do {

     NSLog(@ "%@" ,[arr objectAtIndex:i]);

     i++;

} while (i<[arr count]);

 

//第六種，while-do

int j = 0 ;

while (j<[arr count]) {

     NSLog(@ "%@" ,[arr objectAtIndex:j]);

     j++;

}

//第七種，普通for循環

for ( int m = 0 ; m<[arr count]; m++) {

     NSLog(@ "%@" ,[arr objectAtIndex:m]);

}