Objective c addObjectsFromArray与mutableCopy
我有以下代码:Objective c addObjectsFromArray与mutableCopy,objective-c,cocoa,cocoa-touch,arrays,nsarray,Objective C,Cocoa,Cocoa Touch,Arrays,Nsarray,我有以下代码: self.itemsCopy = [self.items mutableCopy]; //[self.itemsCopy addObjectsFromArray:self.items]; NSLog(@"------- BEFORE APPEND --------"); NSLog(@"items count: %d",[items count]); NSLog(@"itemsCopy count: %d",[itemsCopy coun
self.itemsCopy = [self.items mutableCopy];
//[self.itemsCopy addObjectsFromArray:self.items];
NSLog(@"------- BEFORE APPEND --------");
NSLog(@"items count: %d",[items count]);
NSLog(@"itemsCopy count: %d",[itemsCopy count]);
我的结果是:
------- BEFORE APPEND --------
items count: 15
itemsCopy count: 15
------- BEFORE APPEND --------
items count: 15
itemsCopy count: 0
但是,如果我将第一行从mutableCopy更改为addObjectsFromArray:
[self.itemsCopy addObjectsFromArray:self.items];
我的新结果是:
------- BEFORE APPEND --------
items count: 15
itemsCopy count: 15
------- BEFORE APPEND --------
items count: 15
itemsCopy count: 0
为什么mutableCopy填充ItemScope,而addObjectsFromArray不填充?因为您没有使用NSMutableArray初始化self.ItemScope,所以它为零。因为您没有使用NSMutableArray初始化它,所以self.ItemScope为零