ios中数组的 firstObject 和 [0]的区别
2016-07-04 11:37
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firstObject 和 [0]的区别-iOS初学
两者都是取第一个元素。区别在于数组为空时,firstObject会返回nil,但是[0]发生数组下标越界导致崩溃。
@property (nullable,
nonatomic, readonly) ObjectType firstObject
NS_AVAILABLE(10_6,
4_0);
@property (nullable,
nonatomic, readonly) ObjectType lastObject;
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