php判断字符串是数字

<?php
function isNumber($str) {
    return is_numeric($str);
}

// 测试
$testStrings = ["123", "123.45", "1.23e4", "abc", "123abc"];

foreach ($testStrings as $str) {
    if (isNumber($str)) {
        echo "'$str' 是数字\n";
    } else {
        echo "'$str' 不是数字\n";
    }
}
?>

<?php
function isStrictNumber($str) {
    return preg_match('/^[+-]?(\d+(\.\d*)?|\.\d+)([eE][+-]?\d+)?$/', $str);
}

// 测试
$testStrings = ["123", "123.45", "1.23e4", "abc", "123abc"];

foreach ($testStrings as $str) {
    if (isStrictNumber($str)) {
        echo "'$str' 是严格数字\n";
    } else {
        echo "'$str' 不是严格数字\n";
    }
}
?>