将带有小数点和千位分隔符的字符串可互换地转换为 PHP 中的浮点数 [关闭]

Question

我想知道如何能够将任何字符串转换为浮点数，并且可以切换千位分隔符和十进制指针。这在处理欧洲和美国格式时非常有用。例如。 '2,192,520.12' 或 '2.192.520,12'

Answer 1

您可以通过正则表达式删除除最后一个以外的所有分隔符

[,.](?=.+[,.])

所以你得到2192520.12 或2192520,12。并将逗号替换为点。这将是正确的数字格式

$re = '/[,.](?=.+[,.])/m';
$subst = '';
$result = preg_replace($re, $subst, $str);
$result = str_replace(',', '.', $result);  // 2192520.12

如果您想将数字处理为1,000，那么我们应该设置该小数部分最多可以包含 2 位数字。正则表达式将是

[,.](?=.+[,.]|\d{3})

否则你无法区分 1.027（一个带小数）和 1027

demo

Answer 2

我想出了什么：

function makeFloat( $numberString ) {
    $commaPos = strrpos( $numberString, ',' );
    $dotPos = strrpos( $numberString, '.' );

    if ( $commaPos === false && $dotPos === false ) {
        // string does not contain comma or a dot
        return (float) $numberString;
    }

    if ( $commaPos === false ) {
        // string does not contain a comma, it does contain a dot
        if ( strpos( $numberString, '.' ) === $dotPos ) { // strpos vs strrpos
            // string contains a single dot, assume the dot is the decimal pointer
            return (float) $numberString;
            // if the string is 1.000 this will cast to 1
            // we do not know if this is a thousand separator
        }
        // string contains multiple dots, assume the dots are thousand separators 
        // (again, string does not contains commas)
        return (float) str_replace( '.', '', $numberString );
    }
    // string contains a comma

    if ( $dotPos === false ) {
        // string does not contain a dot, it does contain a comma
        if ( strpos( $numberString, ',' ) === $commaPos ) { // strpos vs strrpos
            // string contains a single comma, assume the comma is the decimal pointer
            return (float) str_replace( ',', '.', $numberString );
            // if the string is 1,000 this will cast to 1
            // we do not know if this is a thousand separator
        }
        // string contains multiple commas, assume the commas are thousand separators
        return (float) str_replace( ',', '', $numberString );
    }
    // string contains both a comma and a dot

    return $dotPos > $commaPos ?
        // the dot is the decimal pointer
        (float) str_replace( ',', '', $numberString ) :
        // the comma is the decimal pointer
        (float) strtr( $numberString, [ '.' => '', ',' => '.' ] );
}

请随意扩展此方法，我很想看看我们能想出什么。