用php将空格替换为下划线

这是一个非常新的问题，但我就是不知道问题出在哪里 所以请容忍我

这就是我想要实现的->$new='天哪，这是一个愚蠢的错误'

下面是我从这段代码中得到的->$new='天哪，这是一个愚蠢的错误'

使用以下功能：

<?php
    $old = 'OMG_This_Is_A_One_Stupid_Error';
    $new = str_replace(' ', '_', $old);
    echo $old; // will output OMG This Is A One Stupid error
?>

反转参数以获得反转效果

<?php
    $old = 'OMG This Is A One Stupid_Error';
    $new = str_replace('_', ' ', $old);
    echo $old; // will output OMG_This_Is_A_One_Stupid error
?>

---

请允许我把你介绍给

你可以用

如果只希望源字符串中的下划线替换为空格，请使用以下命令：

$source = 'OMG This Is A One Stupid Error'; //just an example

// $new is: OMG_This_Is_A_One_Stupid_Error
$new = str_replace(' ', '_', $source);

如果源字符串是较大字符串的子字符串，则可以执行以下操作：

$source     = 'This is a question for SO. '
            . 'OMG This Is A One Stupid Error';
$to_replace = 'OMG This Is A One Stupid Error';
$target     = str_replace(' ', '_', $to_replace);

// Finally replace the target string
$new = str_replace($to_replace, $target, $source)

// $new is: This is a question for SO. OMG_This_Is_A_One_Stupid_Error

---

你可能想抬头看看，或者换言之：你不仅重新发明了轮子，还发明了火和用石头杀死动物作为食物；参数顺序错误：mixed str_replace mixed$search，mixed$replace，mixed$subject[，int&$count]

$source = 'OMG This Is A One Stupid Error'; //just an example

// $new is: OMG_This_Is_A_One_Stupid_Error
$new = str_replace(' ', '_', $source);

$source     = 'This is a question for SO. '
            . 'OMG This Is A One Stupid Error';
$to_replace = 'OMG This Is A One Stupid Error';
$target     = str_replace(' ', '_', $to_replace);

// Finally replace the target string
$new = str_replace($to_replace, $target, $source)

// $new is: This is a question for SO. OMG_This_Is_A_One_Stupid_Error