Show a number to two decimal places

问题

What\'s the correct way to round a PHP string to two decimal places?

$number = \"520\"; // It\'s a string from a database

$formatted_number = round_to_2dp($number);

echo $formatted_number;

The output should be 520.00;

How should the round_to_2dp() function definition be?

回答1:

You can use number_format():

return number_format((float)$number, 2, '.', '');

Example:

$foo = "105";
echo number_format((float)$foo, 2, '.', '');  // Outputs -> 105.00

This function returns a string.

回答2:

Alternatively,

$padded = sprintf('%0.2f', $unpadded); // 520 -> 520.00

回答3:

Use round() (use if you are expecting a number in float format only, else use number_format() as an answer given by Codemwnci):

echo round(520.34345, 2);   // 520.34
echo round(520.3, 2);       // 520.3
echo round(520, 2);         // 520

From the manual:

Description:
float round(float $val [, int $precision = 0 [, int $mode = PHP_ROUND_HALF_UP ]]);
Returns the rounded value of val to specified precision (number of digits after the decimal point). precision can also be negative or zero (default).

...

Example #1 `round()` examples

<?php
    echo round(3.4);         // 3
    echo round(3.5);         // 4
    echo round(3.6);         // 4
    echo round(3.6, 0);      // 4
    echo round(1.95583, 2);  // 1.96
    echo round(1241757, -3); // 1242000
    echo round(5.045, 2);    // 5.05
    echo round(5.055, 2);    // 5.06
?>

Example #2 mode examples

<?php
    echo round(9.5, 0, PHP_ROUND_HALF_UP);   // 10
    echo round(9.5, 0, PHP_ROUND_HALF_DOWN); // 9
    echo round(9.5, 0, PHP_ROUND_HALF_EVEN); // 10
    echo round(9.5, 0, PHP_ROUND_HALF_ODD);  // 9

    echo round(8.5, 0, PHP_ROUND_HALF_UP);   // 9
    echo round(8.5, 0, PHP_ROUND_HALF_DOWN); // 8
    echo round(8.5, 0, PHP_ROUND_HALF_EVEN); // 8
    echo round(8.5, 0, PHP_ROUND_HALF_ODD);  // 9
?>

回答4:

http://php.net/manual/en/function.round.php

e.g.

echo round(5.045, 2);    // 5.05

echo round(5.055, 2);    // 5.06

回答5:

Try:

$number = 1234545454; 
echo  $english_format_number = number_format($number, 2);

The output will be:

1,234,545,454.00

回答6:

You can use the PHP printf or sprintf functions:

Example with sprintf:

$num = 2.12;
echo sprintf("%.3f", $num);

You can run the same without echo as well. Example: sprintf("%.3f", $num);

Output:

2.120

Alternatively, with printf:

echo printf("%.2f", $num);

Output:

2.124

回答7:

Another more exotic way to solve this issue is to use bcadd() with a dummy value for the $right_operand of 0.

$formatted_number = bcadd($number, 0, 2);

回答8:

Use the PHP number_format() function.

For example,

$num = 7234545423;
echo number_format($num, 2);

The output will be:

7,234,545,423.00

回答9:

Use the PHP number_format() function.

回答10:

round_to_2dp is a user-defined function, and nothing can be done unless you posted the declaration of that function.

However, my guess is doing this: number_format($number, 2);

回答11:

bcdiv($number, 1, 2) // 2 varies for digits after the decimal point

This will display exactly two digits after the decimal point.

Advantage:

If you want to display two digits after a float value only and not for int, then use this.

回答12:

For conditional rounding off ie. show decimal where it's really needed otherwise whole number

123.56 => 12.56

123.00 => 123

$somenumber = 123.56;

$somenumber = round($somenumber,2);

if($somenumber == intval($somenumber))
{
    $somenumber = intval($somenumber);
}

echo $somenumber; // 123.56


$somenumber = 123.00;

$somenumber = round($somenumber,2);

if($somenumber == intval($somenumber))
{
    $somenumber = intval($somenumber);
}

echo $somenumber; // 123

回答13:

I make my own.

$decimals = 2;
$number = 221.12345;
$number = $number * pow(10, $decimals);
$number = intval($number);
$number = $number / pow(10, $decimals);

回答14:

$twoDecNum = sprintf('%0.2f', round($number, 2));

The rounding correctly rounds the number and the sprintf forces it to 2 decimal places if it happens to to be only 1 decimal place after rounding.

回答15:

$retailPrice = 5.989;
echo number_format(floor($retailPrice*100)/100,2, '.', '');

It will return 5.98 without rounding the number.

回答16:

$number = sprintf('%0.2f', $numbers); // 520.89898989 -> 520.89

This will give you 2 number after decimal.

回答17:

Here I get two decimals after the . (dot) using a function...

function truncate_number($number, $precision = 2) {

    // Zero causes issues, and no need to truncate
    if (0 == (int)$number) {
        return $number;
    }

    // Are we negative?
    $negative = $number / abs($number);

    // Cast the number to a positive to solve rounding
    $number = abs($number);

    // Calculate precision number for dividing / multiplying
    $precision = pow(10, $precision);

    // Run the math, re-applying the negative value to ensure
    // returns correctly negative / positive
    return floor( $number * $precision ) / $precision * $negative;
}

Results from the above function:

echo truncate_number(2.56789, 1); // 2.5
echo truncate_number(2.56789);    // 2.56
echo truncate_number(2.56789, 3); // 2.567

echo truncate_number(-2.56789, 1); // -2.5
echo truncate_number(-2.56789);    // -2.56
echo truncate_number(-2.56789, 3); // -2.567

New Correct Answer

Use the PHP native function bcdiv

echo bcdiv(2.56789, 1, 1);  // 2.5
echo bcdiv(2.56789, 1, 2);  // 2.56
echo bcdiv(2.56789, 1, 3);  // 2.567
echo bcdiv(-2.56789, 1, 1); // -2.5
echo bcdiv(-2.56789, 1, 2); // -2.56
echo bcdiv(-2.56789, 1, 3); // -2.567

回答18:

If you want to use two decimal digits in your entire project, you can define:

bcscale(2);

Then the following function will produce your desired result:

$myvalue = 10.165445;
echo bcadd(0, $myvalue);
// result=10.11

But if you don't use the bcscale function, you need to write the code as follows to get your desired result.

$myvalue = 10.165445;
echo bcadd(0, $myvalue, 2);
// result=10.11

To know more

BC Math Functions
bcscale

回答19:

Number without round

$double = '21.188624';
echo intval($double) . '.' . substr(end(explode('.', $double)), 0, 2);

回答20:

Here's another solution with strtok and str_pad:

$num = 520.00
strtok(round($num, 2), '.') . '.' . str_pad(strtok('.'), 2, '0')

回答21:

You can use PHP round() function.

echo round(3.4);         // 3
echo round(3.5);         // 4
echo round(3.6);         // 4
echo round(3.6, 0);      // 4
echo round(1.95583, 2);  // 1.96
echo round(1241757, -3); // 1242000
echo round(5.045, 2);    // 5.05
echo round(5.055, 2);    // 5.06

来源：https://stackoverflow.com/questions/4483540/show-a-number-to-two-decimal-places

标签

php

formatting

numbers

rounding

number-formatting