从字符串中删除整个黑名单单词

Question

下面的代码的问题在于它从字符串中删除了 characters 而不是 words。

$str = "In a minute, remove all of the corks from these bottles in the cellar";

$useless_words = array("the", "of", "or", "in", "a");

$newstr = str_replace($useless_words, "", $str);

以上输出：

In mute, remove ll   cks from se bottles   cellr

我需要的输出是：

minute, remove all corks from these bottles cellar

我假设我无法使用

str_replace()

。我可以做什么来实现这个目标？

Answer 1

preg_replace将完成这项工作：

$str = "The game start in a minute, remove all of the corks from these bottles in the cellar";
$useless_words = array("the", "of", "or", "in", "a");
$pattern = '/\h+(?:' . implode($useless_words, '|') . ')\b/i';
$newstr = preg_replace($pattern, "", $str);
echo $newstr,"\n";

输出：

The game start minute, remove all corks from these bottles cellar

说明：

图案看起来像：

/\h+(?:the|of|or|in|a)\b/i

/                   : regex delimiter
  \h+               : 1 or more horizontal spaces
  (?:               : start non capture group
    the|of|or|in|a  : alternatives for all the useless words
  )                 : end group
  \b                : word boundary, make sure we don't have a word character before
/i                  : regex delimiter, case insensitive

Answer 2

$useless_words = array(" the ", " of ", " or ", " in ", " a ");
$str = "In a minute, remove all of the corks from these bottles in the 
cellar";

$newstr = str_replace($useless_words, " ", $str);

$trimmed_useless_words = array_map('trim',$useless_words);
$newstr2 = '';
foreach ($trimmed_useless_words as &$value) {
   if (strcmp($value, substr($newstr,0,strlen($value)))){
       $newstr2 = substr($newstr, strlen($value) );
       break;
   }
}
if ($newstr2 == ''){
    $newstr2 = $newstr; 
}
echo $newstr2;

Answer 3

除了强制整个单词与单词边界匹配之外，还可以使用条件表达式来消耗前导或尾随空白字符（但不能同时使用两者！）。

代码：（演示）

$str = "The game start in a minute, remove all of the corks from these bottles in the cellar they're in";
$useless_words = ["the", "of", "or", "in", "a"];

var_dump(
    preg_replace('/(\s+)?\b(?:' . implode('|', $useless_words) . ')\b(?(1)|\s+)/i', '', $str)
);

输出：

string(69) "game start minute, remove all corks from these bottles cellar they're"

请注意，前导

The

加上尾随空格被删除，最后一个

in

及其前导空格被删除，

all of the corks

变成了

all corks

，仅由一个空格分隔。