Can we convert exponential or scientific notation number to decimal notation?

Question

I have a number 3.43E-6 and I need to convert it into 0.00000343. Is that possible with PHP?

I tried PHP number_format and also tried using the answer of this post (float), but it does not work as expected. The mentioned number is not a string but a decimal value, and by the answer mentioned in that post we can get the normal whole number from positive exponential values (5.78e5, 3.14e5), but not working for the negative exponential values like 3.43E-6, 6.24464e-7, 5.864e-5. It returns the same value that we give as an input if we use a negative exponential value.

Number: 3.43E-6

Expected result: 0.00000343

@Nigel Ren, Sorry for the misunderstanding! I meant 3.43E-6 as a number. — vimal.roy, Mar 31 '23 at 11:57
The marked dupe doesn't seem to handle dynamic cases like 2.54E-14 or 99.87E-2 etc — nice_dev, Mar 31 '23 at 12:15
@nice_dev feel free to add a matching answer to the other question — Nico Haase, Mar 31 '23 at 13:23
But "0.00000343" is still not an integer, or say, whole number . — tsh, Apr 07 '23 at 07:10

Deepak Kumar · Accepted Answer · 2023-03-31T12:03:30.147

1

yes it is possible try this and you can modify this 8 if u want more decimal '%.8f

$number = 3.43E-6;
$decimal = sprintf('%.8f', $number);
echo '$' . $decimal; // output: $0.00000343

also this is another example

$decimal = sprintf('%.10f', $number);
echo '$' . $decimal; // output: $0.0000034300

there is other way of doing this :

$converted_number = number_format($number, 8, '.', '');
echo $converted_number; // Output: 0.00000343

edited Mar 31 '23 at 12:03

answered Mar 31 '23 at 11:48

Deepak Kumar

56
3

1

Thank you!!! Got the expected result using the mentioned answer. – vimal.roy Mar 31 '23 at 11:53
2

`'%.8f'` cannot be a hardcoded value. It should depend upon what comes after `E` – nice_dev Mar 31 '23 at 11:57
@nice_dev yes i posted two ways of doing it..... – Deepak Kumar Mar 31 '23 at 12:04
3

@DeepakKumar But it still hardcoded. From where are you getting that magic number 8 programmatically? – nice_dev Mar 31 '23 at 12:13

score 1 · Answer 2 · answered Apr 10 '23 at 06:09

Using the answers provided, I created a function like the one below, which seems to be working fine.

function convertExponentialToDecimal($number) {

  $full_string = $number;
  $num_string_without_dollar = str_replace('$', '', $full_string);

  $is_exponential = preg_match('/^\$?[+-]?\d+(\.\d+)?[Ee][+-]?\d+$/i', $num_string_without_dollar); // check if the number is in exponential notation
  if ($is_exponential) {
    
      $decimal = sprintf("%.20f", $num_string_without_dollar);
      $decimal = bcmul($decimal, '1', 20);
      $decimal = rtrim($decimal, '0');
      $decimal = rtrim($decimal, '.');

  } else {
      $decimal = (float)$num_string_without_dollar;
  }

  return $decimal;

}

This function can convert the exponential values to a whole number (in decimal notation).

echo convertExponentialToDecimal('6.20503e-7');

The above code gives a result of 0.000000620503.

I don't know if this is the proper solution or not; however, it is working correctly.

Thank you all!

Can we convert exponential or scientific notation number to decimal notation?

2 Answers2