使用一元运算符（+）。例如：

$n1 = +'7';
$n2 = '2.34';
$n2 = +$n1;

var_dump（$n1）：int（7）var_dump（$n2）：浮点（2.34）

$a = "10";

$b = (int)$a;

您可以使用它在PHP中将字符串转换为int。

如果您希望为$value=“0.4”获取浮点值，但为$value=“4”获取int值，则可以编写：

$number = ($value == (int) $value) ? (int) $value : (float) $value;

它有点脏，但很管用。

如果你事先不知道你有一个浮点数还是一个整数，如果字符串可能包含特殊字符（如空格、欧元等），并且如果它可以包含多于1个点或逗号，您可以使用此功能：

// This function strip spaces and other characters from a string and return a number.
// It works for integer and float.
// It expect decimal delimiter to be either a '.' or ','
// Note: everything after an eventual 2nd decimal delimiter will be removed.
function stringToNumber($string) {
    // return 0 if the string contains no number at all or is not a string:
    if (!is_string($string) || !preg_match('/\d/', $string)) {
        return 0;
    } 

    // Replace all ',' with '.':
    $workingString = str_replace(',', '.', $string);

    // Keep only number and '.':
    $workingString = preg_replace("/[^0-9.]+/", "", $workingString);

    // Split the integer part and the decimal part,
    // (and eventually a third part if there are more 
    //     than 1 decimal delimiter in the string):
    $explodedString = explode('.', $workingString, 3);

    if ($explodedString[0] === '') {
        // No number was present before the first decimal delimiter, 
        // so we assume it was meant to be a 0:
        $explodedString[0] = '0';
    } 

    if (sizeof($explodedString) === 1) {
        // No decimal delimiter was present in the string,
        // create a string representing an integer:
        $workingString = $explodedString[0];
    } else {
        // A decimal delimiter was present,
        // create a string representing a float:
        $workingString = $explodedString[0] . '.' .  $explodedString[1];
    }

    // Create a number from this now non-ambiguous string:
    $number = $workingString * 1;

    return $number;
}

您通常不需要这样做，因为在大多数情况下，PHP会强制您使用类型。对于确实要显式转换类型的情况，请将其强制转换为：

$num = "3.14";
$int = (int)$num;
$float = (float)$num;

在PHP中，您可以使用intval（string）或floatval（字符串）函数将字符串转换为数字。