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Home Backend Development PHP Tutorial 一个函数里面用一个return 好 还是多个return 好?

一个函数里面用一个return 好 还是多个return 好?

Jun 06, 2016 pm 08:37 PM
php

<code><?php function dmeo1($num)
 {
    if($num>0)
    {
        return true;
    }
    else
    {
        return false;
    }
 }




 function dmeo2($num)
 {    
    $status = null;

    if($num>0)
    {
       $status  = true;
    }
    else
    {
       $status  = false;
    }

    return $status;
 }
</code>
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回复内容:

<code><?php function dmeo1($num)
 {
    if($num>0)
    {
        return true;
    }
    else
    {
        return false;
    }
 }




 function dmeo2($num)
 {    
    $status = null;

    if($num>0)
    {
       $status  = true;
    }
    else
    {
       $status  = false;
    }

    return $status;
 }
</code>
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尽早return,不要走多余的流程

<code>php</code><code>// 一般情况
function foo($num) {
    if ($num>0) {
        return true;
    }
    return false;
}


// 特殊情况:正好需要返回bool值
function bar($num) {
    return $num>0;
}
</code>
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你的代码很好,我帮你重写了一遍:

原始代码:

<code>javascript</code><code>function dmeo1($num)
{
    if($num>0)
    {
        return true;
    }
    else
    {
        return false;
    }
}
</code>
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重写一遍:

<code>javascript</code><code>function dmeo1($num)
{
    flag = $num > 0;

    if(flag === true)
    {
        return true;
    }
    else
    {
        return false;
    }
}
</code>
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代码思路瞬间清晰了。

多少return没关系,要保持代码的高度简洁易懂

<code>function dmeo($num) {
    return $num > 0;
}
</code>
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<code>function dmeo3($num)
{
    return $num>0;
}
</code>
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灵活的根据结构定

<code>function dmeo($num)
 {
    return $num>0;   
 }
</code>
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那个没有高亮的是“returm”?

除去 guard condition 型的 return, 多个 return 是不是说明函数复杂了, 职责过多而需要重新考虑设计了.

尽早返回。。。

该return的时间就return,也没有强制说几个return不好,毕竟一个return代表的是一个逻辑片段,所以其实只要逻辑清晰,代码清晰就够了!

应该尽早输出return,这样会提高效率,就是说本来你经确定数据已得到,对于之后的代码,执行的意义也不大

同意@城南往事的看法,如果一个函数在第一行就可以return,那么就没必要等到最后一行,效率先不说,可读性绝对是有差别的!

使用哪种方式能带使代码更加清晰就使用哪种,不过通常情况下使用多个return是一个更佳的选择。
具体可以参考《重构-改善代码既有设计》9.5节的介绍。

老师说啦,程序应该一个出口,避免使用多return,break

如果程序中有很多防御性设计,在出错之后程序就要退出,那么就要在每次出错的时候直接return,否则就这样了:一个函数里面用一个return 好 还是多个return 好?
如果程序就是一个算法,有确定的返回值类型,那么我认为还是一个return好:

<code>function getValue($x) {
    $y = 0;
    if ($x>0) {
        $y = $x*$x;
    } else if ($x == 0) {
        $y = -1;
    } else {
        $y = 1/$x;
    }
    return $y;
}
</code>
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http://stackoverflow.com/questions/36707/should-a-function-have-only-one-return-statement

我个人觉得第一种好,如果当一个方法很长时,用return可以看出在哪里直接退出,用第二种方法的话是不是得看到最后?

<code> function dmeo2($num)
 {    
    $status = false;

    if($num>0)
    {
       $status  = true;
    }

    return $status;
 }
</code>
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我比较习惯这种写法

还是看具体情况吧,如果一些前提判断,自然需要提前返回(也就是第一种)。第二种应该是那种逻辑的操作,最后给一个执行的状态。

我更倾向于第二种,用变量去控制程序返回的结果,而不是在程序各个点直接return,程序控制,怎么会进行多余的流程呢

其实很简单,分支越少越好

为什么你们都不给他的方法改个名?

<code>function isNonNegative($num) {
    return $num > 0;
}
</code>
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