如何“传递”一个可变数量的参数NSString的+ stringWithFormat： [英] How to "pass on" a variable number of arguments to NSString's +stringWithFormat:

问题描述

我想在Objective-C中编写一个函数，如下面的一个函数，它接受可变数量的参数，并将这些参数传递给 + stringWithFormat： 。我知道 vsnprintf ，但这将意味着将NSString'format'转换为C和回来（也将意味着转换其中的格式化占位符...）。

I would like to write a function in Objective-C such as the one below, that takes a variable number of arguments, and passes those arguments on to +stringWithFormat:. I know about vsnprintf, but that would imply converting the NSString 'format' to C and back (and would also mean converting the formatting placeholders within it as well...).

下面的代码编译，但当然不会像我想要的那样：）

The code below compiles, but of course does not behave as I want :)

NSString *estr(NSString *format, ...) {
    va_list args;
    va_start(args, format);
    NSString *s = [NSString stringWithFormat:format, args];
    va_end(args);
    return s;
}

基本上是： va_list -friendly版本的 + stringWithFormat：方法，还是可以写一个？

Basically: is there a va_list-friendly version of the +stringWithFormat: method, or is it possible to write one?

推荐答案

initWithFormat：arguments：

NSString *estr(NSString *format, ...) {
    va_list args;
    va_start(args, format);
    NSString *s = [[[NSString alloc] initWithFormat:format arguments:args] autorelease];
    va_end(args);
    return s;
}

它们似乎没有方便的构造函数stringWith ...版本

they don't seem to have a convenience constructor "stringWith..." version

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