iphone - NSString stringWithFormat 很慢

Question

在 Objective-C 中，该方法stringWithFormat:似乎非常慢，实际上是我们的一个应用程序中的一个很大的瓶颈（我们使用分析器来发现这一点）。有没有办法优化它或使用一些更快的 C 代码？

Answer 1

是sprintf的，在 c http://www.cplusplus.com/reference/cstdio/sprintf/ 中使用，然后将 char* 推送到 NSString 中[NSString stringWithUTF8:];

例子：

char cString[255];
sprintf (cString, "%d", 36);
NSString* OCstring = [[NSString alloc] initWithUTF8String:cString];

Answer 2

If you're doing extensive string manipulations and operations - it sounds like you might well be doing so, and NSString really is becoming a bottleneck for your app, I recommend trying to use C++ for your string needs rather then C.

Apple admits that while NSString is great, it is top level, in fact, to make their autocorrect algorithm's for iOS they ran into a similar problem, NSString was too slow to compute and compare so many things. They then switched to C++ and got all the performance they needed.

Just a suggestion. You should definitely put up some code, I am surprised this is happening to you unless you're doing some awesome new feature !