使用@ [array，of items] vs [NSArray arrayWithObjects:] [英] Using @[array, of, items] vs [NSArray arrayWithObjects:]

问题描述

两者之间是否有区别

NSArray *myArray = @[objectOne, objectTwo, objectThree];

和

NSArray *myArray = [NSArray arrayWithObjects:objectOne, objectTwo, objectThree, nil];

一个人优先于另一个人吗?

Is one preferred over the other?

推荐答案

它们几乎相同，但不完全相同. Objective-C Literals 上的Clang文档指出:

They are almost identical, but not completely. The Clang documentation on Objective-C Literals states:

数组文字表达式扩展为对 +[NSArray arrayWithObjects:count:]，它验证所有对象都是 非零.可变格式+[NSArray arrayWithObjects:]使用nil作为 参数列表终止符，可能导致数组格式错误 对象.

Array literal expressions expand to calls to +[NSArray arrayWithObjects:count:], which validates that all objects are non-nil. The variadic form, +[NSArray arrayWithObjects:] uses nil as an argument list terminator, which can lead to malformed array objects.

所以

NSArray *myArray = @[objectOne, objectTwo, objectThree];

如果objectTwo == nil会抛出运行时异常，但是

would throw a runtime exception if objectTwo == nil, but

NSArray *myArray = [NSArray arrayWithObjects:objectOne, objectTwo, objectThree, nil];

在这种情况下，将使用一个元素创建一个数组.

would create an array with one element in that case.

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