printf, sprintf print at least two decimal places

I'm trying to figure out how to use sprintf to print at least two decimal places and no leading zeros. For instance

input:

23
23.0
23.5
23.55
23.555
23.0000

output:开发者_如何学Go

23.00
23.00
23.50
23.55
23.555
23.00

any formatting help would be appreciated

---

There is no such built-in format specifier. You could check if the number to be printed has two or fewer decimals (round to two decimals and compare), and if so use %.02f. If the number has more decimals, use a %g specifier. Here's an example in Ruby:

def print_two_dec(number)
  rounded = (number*100).to_i / 100.0
  if number == rounded
    printf "%.02f\n", number
  else
    printf "%g\n", number
  end
end

[ 23, 23.0, 23.5, 23.55, 23.555 ].each do |number|
  print_two_dec(number)
end

Outputs:

23.00
23.00
23.50
23.55
23.555

---

in PHP you could use

<?php
$number = 0.56;
echo sprintf("%0.2f",$number);

---

In PHP, you may use the number_format function for this purpose, too, which also allows you to change delimiters.

---

In php this is what I did (inspired by this post). Maybe not the most elegant but... I made a function for printing numbers as strings. I wanted to be able to have flexibility so I have a couple of parameters.

PHP:

function print_num($num,$numdec,$atleast = false,$max_dec = -1)
{

  $ret_norm = false;

  if (!$atleast)
    $ret_norm = true;
  else //atleast = true
  {
    //Want at least $numdec decimals

    //Do we have two or fewer and want to return two or fewer?
    if ($num == ((int)($num*100)/100) & $numdec <= 2 )
      $ret_norm = true;
    else
    {
      //See if we have enough dec. already
      $just_dec = substr((string)$num,strpos((string)$num,".") + 1);
      if ($numdec >= strlen($just_dec))
        $ret_norm = true;
      else
      {
        //More decimals than at least value - make sure we don't go over max if set
        if ( $max_dec >= 0 && strlen($just_dec) > $max_dec )
        {
          //Confine to max_dec length
          $ret_norm = true;
          $numdec = $max_dec;                   //Set for sprintf below
          $num = number_format($num,$max_dec);  //Round the value so doesn't just chop off

        }
        else if ($max_dec >= 0)
          $ret_norm = false;
      } //else
    } //else
  } //else atlest

  if ($ret_norm)
    return sprintf("%0.".$numdec."f",$num);
  else
      return sprintf("%s",$num); //print as is

} //print_num

And to call the function (to have at least two decimals but max 4:

print_num($mynum,2,true,4);

If the number is 34.1, you get 34.10

If the number is 34.12345 you get 34.1235

etc.

---

Does "23.555".toFixed(2) not do what I think it does? (Javascript)