真抓狂了……
大意如下：
$update=['f1'=>121.231,'f2'=>2312.12, 'f3'=>31.1231,'f4'=>213.12,'fv'=>3189.21321];$month=['m1'=>123.1289,'m2'=>123.23198, 'm3'=>23.21,'m4'=>138.21,'mv'=>1231.81]; foreach($update as &$v){ $v=round($v,4); } foreach($month as $k=>$v){ $update[$k]=round($v,4); } 请各位高人先看上面的代码，这个应该没有问题吧？有问题请指出来，我抓狂了，同时也不用看下面那一长大把啦的了……
核心就是将两个数组合并在一起（其他的实现方法先不谈，就只先用这个），并且保留4位小数
如果上面的代码没有问题，请看我下面的调试。
--------------------------debug-------------------------
实际运行中发现fv字段还是保留了其小数位一大堆，总之没有执行round运算，让我开始怀疑人生了
代码中pr（print_r）看数据，发现在经过了update的foreach后都还是正常的，但是在进入month循环后就不正常了
整理后的调试代码见下：
if($debug_flag){ echo('原始数据');BR(); PR($update); } foreach($update as $k=>&$v){ $v=round($v,4); } //实在没有整明白为什么update的最后一个fv不进行四舍五入呢？ if($debug_flag){ echo('update foreach 循环后数据');BR(); PR($update); echo('进入month循环');BR(); echo('month原始数据');BR(); PR($month); } foreach($month as $k=>$v){ if($debug_flag){ echo('in month ');BR(); PR($update); PR($k);BR(); } $update[$k]=round($v,4); if($debug_flag){ PR($update); echo('month 循环中数据');BR(); } } if($debug_flag){ echo('month循环后数据');BR(); PR($update); PR($month); die(); } 配套的调试结果见下：
原始数据Array( [f1] => 596.4 [f2] => 604.5 [f3] => 600.3325 [f4] => 602.0825 [fv] => 600.85900353103)update foreach 循环后数据Array( [f1] => 596.4 [f2] => 604.5 [f3] => 600.3325 [f4] => 602.0825 [fv] => 600.859)进入month循环month原始数据Array( [m0] => 0 [m1] => 596.4 [m2] => 604.5 [m3] => 600.3325 [m4] => 602.0825 [mv] => 600.85900353103)in monthArray( [f1] => 596.4 [f2] => 604.5 [f3] => 600.3325 [f4] => 602.0825 [fv] => 0)m0Array( [f1] => 596.4 [f2] => 604.5 [f3] => 600.3325 [f4] => 602.0825 [fv] => 0 [m0] => 0)month 循环中数据in monthArray( [f1] => 596.4 [f2] => 604.5 [f3] => 600.3325 [f4] => 602.0825 [fv] => 596.4 [m0] => 0)m1Array( [f1] => 596.4 [f2] => 604.5 [f3] => 600.3325 [f4] => 602.0825 [fv] => 596.4 [m0] => 0 [m1] => 596.4)month 循环中数据in monthArray( [f1] => 596.4 [f2] => 604.5 [f3] => 600.3325 [f4] => 602.0825 [fv] => 604.5 [m0] => 0 [m1] => 596.4)m2Array( [f1] => 596.4 [f2] => 604.5 [f3] => 600.3325 [f4] => 602.0825 [fv] => 604.5 [m0] => 0 [m1] => 596.4 [m2] => 604.5)month 循环中数据in monthArray( [f1] => 596.4 [f2] => 604.5 [f3] => 600.3325 [f4] => 602.0825 [fv] => 600.3325 [m0] => 0 [m1] => 596.4 [m2] => 604.5)m3Array( [f1] => 596.4 [f2] => 604.5 [f3] => 600.3325 [f4] => 602.0825 [fv] => 600.3325 [m0] => 0 [m1] => 596.4 [m2] => 604.5 [m3] => 600.3325)month 循环中数据in monthArray( [f1] => 596.4 [f2] => 604.5 [f3] => 600.3325 [f4] => 602.0825 [fv] => 602.0825 [m0] => 0 [m1] => 596.4 [m2] => 604.5 [m3] => 600.3325)m4Array( [f1] => 596.4 [f2] => 604.5 [f3] => 600.3325 [f4] => 602.0825 [fv] => 602.0825 [m0] => 0 [m1] => 596.4 [m2] => 604.5 [m3] => 600.3325 [m4] => 602.0825)month 循环中数据in monthArray( [f1] => 596.4 [f2] => 604.5 [f3] => 600.3325 [f4] => 602.0825 [fv] => 600.85900353103 [m0] => 0 [m1] => 596.4 [m2] => 604.5 [m3] => 600.3325 [m4] => 602.0825)mvArray( [f1] => 596.4 [f2] => 604.5 [f3] => 600.3325 [f4] => 602.0825 [fv] => 600.85900353103 [m0] => 0 [m1] => 596.4 [m2] => 604.5 [m3] => 600.3325 [m4] => 602.0825 [mv] => 600.859)month 循环中数据month循环后数据Array( [f1] => 596.4 [f2] => 604.5 [f3] => 600.3325 [f4] => 602.0825 [fv] => 600.85900353103 [m0] => 0 [m1] => 596.4 [m2] => 604.5 [m3] => 600.3325 [m4] => 602.0825 [mv] => 600.859)Array( [m0] => 0 [m1] => 596.4 [m2] => 604.5 [m3] => 600.3325 [m4] => 602.0825 [mv] => 600.85900353103)
如果您有耐心看完的话，就会发现进入month循环后数据就已经开始在乱变了……
难道foreach或者是数组的$array[$key]=$value还有什么不为人知的东西？
求援手！
回复讨论(解决方案)
调试到这里顺便就把代码改了
$update=array_merge($update,$month,$year); foreach($update as &$v){ $v=round($v,4); } 这个数据就是正常的了，而且也更简短+明了+没有出错！
但原来的代码是啥地方有问题啊？
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$update = array ( 'f1' => 596.4, 'f2' => 604.5, 'f3' => 600.3325, 'f4' => 602.0825, 'fv' => 600.85900353103,);$month = array ( 'm0' => 0, 'm1' => 596.4, 'm2' => 604.5, 'm3' => 600.3325, 'm4' => 602.0825, 'mv' => 600.85900353103,);foreach($update as $k=>&$v){ $v = round($v, 4);}unset($v);foreach($month as $k=>$v){ $update[$k] = round($v, 4);}print_r($update);Array( [f1] => 596.4 [f2] => 604.5 [f3] => 600.3325 [f4] => 602.0825 [fv] => 600.859 [m0] => 0 [m1] => 596.4 [m2] => 604.5 [m3] => 600.3325 [m4] => 602.0825 [mv] => 600.859)
看到区别了吗？我多用了个 unset($v);
其实这是引用惹的祸，你测试的两组数据正好是相同的，如果你把 $month['mv'] 改成 0，立刻就会发现问题了
$update = array ( 'f1' => 596.4, 'f2' => 604.5, 'f3' => 600.3325, 'f4' => 602.0825, 'fv' => 600.85900353103,);$month = array ( 'm0' => 0, 'm1' => 596.4, 'm2' => 604.5, 'm3' => 600.3325, 'm4' => 602.0825, 'mv' => 600.85900353103,);foreach($update as $k=>&$v){ $v = round($v, 4);}unset($v);foreach($month as $k=>$v){ $update[$k] = round($v, 4);}print_r($update);Array( [f1] => 596.4 [f2] => 604.5 [f3] => 600.3325 [f4] => 602.0825 [fv] => 600.859 [m0] => 0 [m1] => 596.4 [m2] => 604.5 [m3] => 600.3325 [m4] => 602.0825 [mv] => 600.859)
看到区别了吗？我多用了个 unset($v);
其实这是引用惹的祸，你测试的两组数据正好是相同的，如果你把 $month['mv'] 改成 0，立刻就会发现问题了
哦，对……忘记引用这回事情了……一般都很少用&，偶尔用用也没有出错……
谢谢！
