iOS 遍历

以NSArray为例。

1、for循环

NSArray *array = [NSArray arrayWithObjects:@0", @"1",@"2",nil];

int count = array.count;

for( int i = 0 ; i < count ;i ++)

{

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

}

for(id obj in array)

{

NSLog(@"%@",obj);

}

2、NSEnumerator

NSEnumerator *enumerator = [array objectEnumerator];

id obj = nil;

while(obj = [enumerator nextObject]){

NSLog(@"obj=%@",obj);

}

3、

//顺序遍历 NSDictionary 同时取key和value

NSDictionary * dic = [NSDictionary dictionaryWithObjectsAndKeys:@"value0",@"key0",@"value1",@"key1", nil];

[dic enumerateKeysAndObjectsUsingBlock:^(id key, id value, BOOL *stop)

{

NSLog(@"value for key %@ is %@ ", key, value);

if ([@"key1" isEqualToString:key])

{

*stop = YES;

}

}];

//顺序遍历 NSArray

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

NSLog(@"%@",array[idx]);

}];

//NSEnumerationReverse 倒序遍历

//NSEnumerationConcurrent 正序遍历

[array enumerateObjectsWithOptions:NSEnumerationReverse usingBlock:^(id  _Nonnull obj, NSUInteger idx, BOOL * _Nonnull stop) {

NSLog(@"%@",array[idx]);

}];