str_starts_with
(PHP 8)
str_starts_with — Checks if a string starts with a given substring
说明
str_starts_with
( string
$haystack
, string $needle
) : bool
Performs a case-sensitive check indicating if
haystack
begins with needle
.
参数
-
haystack
-
The string to search in.
-
needle
-
The substring to search for in the
haystack
.
返回值
Returns true
if haystack
begins with
needle
, false
otherwise.
范例
示例 #1 Using the empty string ''
<?php
if (str_starts_with('abc', '')) {
echo "All strings start with the empty string";
}
?>
以上例程会输出:
All strings start with the empty string
示例 #2 Showing case-sensitivity
<?php
$string = 'The lazy fox jumped over the fence';
if (str_starts_with($string, 'The')) {
echo "The string starts with 'The'\n";
}
if (str_starts_with($string, 'the')) {
echo 'The string starts with "the"';
} else {
echo '"the" was not found because the case does not match';
}
?>
以上例程会输出:
The string starts with 'The' "the" 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_contains() - Determine if a string contains a given substring
- str_ends_with() - Checks if a string ends 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