php 如何检查字符串是否不包含特定短语？
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How to check if a string does not contain a specific phrase?
提问by Dead Girl
How to invert the function of How do I check if a string contains a specific word in PHP?
if (strpos($a,'are') !== false) {
echo 'true';
}
So it echoes trueif areis notfound in $a.
因此，它呼应true，如果are是不中找到$a。
回答by Rottingham
The code here:
这里的代码：
if (strpos($a, 'are') !== false) {
// The word WAS found
}
Means that the word WAS found in the string. If you remove the NOT (!) operator, you have reversed the condition.
表示在字符串中找到单词 WAS。如果删除 NOT (!) 运算符，则条件已颠倒。
if (strpos($a, 'are') === false) {
// The word was NOT found
}
the === is very important, because strpos will return 0 if the word 'are' is at the very beginning of the string, and since 0 loosely equals FALSE, you would be frustrated trying to find out what was wrong. The === operator makes it check very literally if the result was a boolean false and not a 0.
=== 非常重要，因为如果单词 'are' 位于字符串的最开头，strpos 将返回 0，并且由于 0 大致等于 FALSE，您会因试图找出错误而感到沮丧。=== 运算符使它非常严格地检查结果是否是布尔值 false 而不是 0。
As an example,
举个例子，
if (!strpos($a, 'are')) {
// String Not Found
}
This code will say the string 'are' is not found, if $a = "are you coming over tonight?", because the position of 'are' is 0, the beginning of the string. This is why using the === false check is so important.
这段代码会说没有找到字符串'are'，如果$a = "你今晚要过来吗？"，因为'are'的位置是0，字符串的开头。这就是为什么使用 === false 检查如此重要的原因。
回答by Lucas Bustamante
Using strstr():
使用 strstr()：
if (!strstr($var, 'something')) {
// $var does not contain 'something'
}
Or strpos():
或 strpos():
if (strpos($var, 'something') === false) {
// $var does not contain 'something'
}
Or stripos() if you want case-insensitive search.
或者 str ipos() 如果你想要不区分大小写的搜索。
strpos() is a little faster
strpos()快一点
回答by Digital Chris
You'll probably kick yourself when you see it...
当你看到它时，你可能会踢自己......
if (!strpos($a,'are') !== false) {
echo 'true';
}
回答by Pratik Maniar
Try this
尝试这个
$string = "This is beautiful world.";
$$string = "Beautiful";
preg_match('/\b(express\w+)\b/', $string, $x); // matches expression
\b is a word boundary
\w+ is one or more "word" character
\w* is zero or more "word" characters
enter code here
See the manual on escape sequencesfor PCRE.
请参阅有关PCRE转义序列的手册。
回答by H.A.
strpos() !== false gives you a wrong return value, if the search-string is at the beginning of the string. So you better use strstr(), which gives you an accurate result.
strpos() !== false 给你一个错误的返回值，如果搜索字符串在字符串的开头。所以你最好使用 strstr()，它会给你一个准确的结果。
if (!strstr($mystring, 'Hello')) {
// $mystring does not contain 'Hello' nowhere,
// even not at the beginning of the string
}
