Question

如果字符串具有特定结构，我如何使用preg_match()检查php。例如，字符串是：

options:blue;white;yellow;

我想检查字符串是否以字符串开头，后跟:，后跟由;分隔的n个字符串

一些重要的东西 - 字符串可能是西里尔语，而不仅仅是拉丁字母

Answer 1

假设只需要问题中列出的限制，这将验证字符串：

$number = 3;
$regex = sprintf('/^[^:]+:(?:[^;]+;){%d}$/', $number);

if (preg_match($regex, $string)) {
    echo "It matches!";
} else {
    echo "It doesn't match!";
}

以下是使用php -a：

的实际操作示例

php > $number = 3;
php > $regex = sprintf('/^[^:]+:(?:[^;]+;){%d}$/', $number);

php > if (preg_match($regex, 'options:blue;white;yellow;')) {
php {     echo "It matches!";
php { } else {
php {     echo "It doesn't match!";
php { }
It matches!

php > if (preg_match($regex, 'options:blue;white;yellow;green;')) {
php {     echo "It matches!";
php { } else {
php {     echo "It doesn't match!";
php { }
It doesn't match!

您可以将此正则表达式here可视化。让我们分解一下：

/.../          Start and end of the pattern.
^              Start of the string.
[^:]+          At least one character that is not a ':'.
:              A literal ':'.
(?:[^;]+;){N}  Exactly N occurrences of:
                   [^;]+  At least one character that is not a ';'.
                   ;      A literal ';'.
$              End of the string.

preg_match检查字符串是否具有特定结构

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