PHP中变量扩展与sprintf的性能 [英] Performance of variable expansion vs. sprintf in PHP

问题描述

关于性能，两者之间有什么区别

Regarding performance, is there any difference between doing:

$message = "The request $request has $n errors";

和

$message = sprintf('The request %s has %d errors', $request, $n);

在PHP中?

我会说调用一个函数涉及更多的东西，但是我不知道PHP在后台扩展变量名的作用.

I would say that calling a function involves more stuff, but I do not know what's PHP doing behind the scenes to expand variables names.

谢谢！

推荐答案

在所有情况下，第二个都不会更快，因为您提供的双引号字符串也必须解析变量.如果您要进行微优化，则正确的方法是:

In all cases the second won't be faster, since you are supplying a double-quoted string, which have to be parsed for variables as well. If you are going for micro-optimization, the proper way is:

$message = sprintf('The request %s has %d errors', $request, $n);

不过，由于函数调用，解析字符串，转换值等的开销，我仍然相信秒数会更慢(因为@Pekka指出了区别实际上并不重要).但是请注意，两行代码不等价，因为在第二种情况下，$ n转换为整数.如果$ n是没有错误"，则第一行将输出:

Still, I believe the seconds is slower (as @Pekka pointed the difference actually do not matter), because of the overhead of a function call, parsing string, converting values, etc. But please, note, the 2 lines of code are not equivalent, since in the second case $n is converted to integer. if $n is "no error" then the first line will output:

The request $request has no error errors

第二个将输出:

The request $request has 0 errors

这篇关于PHP中变量扩展与sprintf的性能的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！