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HomeBackend DevelopmentPHP TutorialPHP内置的Math函数效率测试_php技巧

本文实例分析了PHP内置的Math函数效率问题。分享给大家供大家参考。具体分析如下:

如题所示,对于没有做过大规模运算的朋友来说,可能还不知道,PHP的Math函数运算原来是如此之慢的,大家还是麻烦点,手写多几句,代码如下:

复制代码 代码如下:
$start = microtime(TRUE);   
for ($i=0; $i     $s = 0;
    for ($j=0; $j        $s += ($j+$i+1) * ($j+$i+1);
    }   
}   
echo microtime(TRUE) – $start;  // output: 0.33167719841003

再对比下用Math函数的代码和结果,代码如下:
复制代码 代码如下:
$start = microtime(TRUE);   
for ($i=0; $i     $s = 0;
    for ($j=0; $j        $s += pow($j+$i+1, 2);
    }
}
echo microtime(TRUE) – $start;   // output: 0.87528896331787

看到木有,效率提升100%!!以前还一直都认为是PHP内置的Math快,真是不测不知道,像取绝对值abs,最大值max,最小值min 等效率都不如原生的 if判断来得快.

总的来说,php运算的确是很慢,真心不适合做大规模的算法运算.希望本文所述对大家的PHP程序设计有所帮助。

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