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    str_contains

    (PHP 8)

    str_contains — Determine if a string contains a given substring

    说明

    str_contains(string $haystack, string $needle): bool

    Performs a case-sensitive check indicating if needle is contained in haystack.

    参数

    haystack

    The string to search in.

    needle

    The substring to search for in the haystack.

    返回值

    Returns true if needle is in haystack, false otherwise.

    范例

    示例 #1 Using the empty string ''

    <?php
    if (str_contains('abc', '')) {
        echo     "Checking the existence of the empty string will always return true";
    }
    ?>

    以上例程会输出：

    Checking the existence of the empty string will always return true

    示例 #2 Showing case-sensitivity

    <?php
    $string     = 'The lazy fox jumped over the fence';

    if (    str_contains($string, 'lazy')) {
        echo     "The string 'lazy' was found in the string\n";
    }

    if (    str_contains($string, 'Lazy')) {
        echo     'The string "Lazy" was found in the string';
    } else {
        echo     '"Lazy" was not found because the case does not match';
    }

    ?>

    以上例程会输出：

    The string 'lazy' was found in the string
"Lazy" was not found because the case does not match

    注释

    注意: 此函数可安全用于二进制对象。

    参见

    • str_ends_with() - Checks if a string ends with a given substring
    • str_starts_with() - Checks if a string starts with a given substring
    • stripos() - 查找字符串首次出现的位置（不区分大小写）
    • strrpos() - 计算指定字符串在目标字符串中最后一次出现的位置
    • strripos() - 计算指定字符串在目标字符串中最后一次出现的位置（不区分大小写）
    • strstr() - 查找字符串的首次出现
    • strpbrk() - 在字符串中查找一组字符的任何一个字符
    • substr() - 返回字符串的子串
    • preg_match() - 执行匹配正则表达式

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    User Contributed Notes 4 notes

    up
    13
    scm6079
    3 years ago
    For earlier versions of PHP, you can polyfill the str_contains function using the following snippet:

    <?php
    // based on original work from the PHP Laravel framework
    if (!function_exists('str_contains')) {
        function     str_contains($haystack, $needle) {
            return     $needle !== '' && mb_strpos($haystack, $needle) !== false;
        }
    }
    ?>
    up
    2
    olivertasche+nospam at gmail dot com
    3 years ago
    The code from "me at daz dot co dot uk" will not work if the word is
    - at the start of the string
    - at the end of the string
    - at the end of a sentence (like "the ox." or "is that an ox?")
    - in quotes
    - and so on.

    You should explode the string by whitespace, punctations, ... and check if the resulting array contains your word OR try to test with a RegEx like this:
    (^|[\s\W])+word($|[\s\W])+

    Disclaimer: The RegEx may need some tweaks
    up
    -7
    kadenskinner at gmail dot com
    3 years ago
    <?php

    $needle     = '@';
    $haystack = 'user@example.com';

    if (!    str_contains($haystack, $needle)){
    echo     'There is not an @ in haystack';
    }else{
    echo     'There is an @ in haystack';
    }
    up
    -37
    me at daz dot co dot uk
    3 years ago
    # Watch out for aberrant partial matches

    $string = 'The lazy fox jumped over the fence';

    if (str_contains($string, 'ox')) {
        echo 'The string "ox" was found in the string because it was a partial match';
    } else {
        echo '"ox" was not found';
    }
    //output: The string "ox" was found in the string because it was a partial match

    # use spaces for full word matching

    $string = 'The lazy fox jumped over the fence';

    if (str_contains($string, ' ox ')) {
        echo 'The string " ox " was found in the string because it was a partial match';
    } else {
        echo '" ox " was not found';
    }
    //output:  " ox " was not found
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