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Re: Placing 'zeros' in front of a number ?

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Am 2012-06-22 05:18, Michael Haufe (TNO) meinte:
> On Thursday, June 21, 2012 7:37:43 PM UTC-5, Mel Smith wrote:
> [...]
>>      I've got a bunch of numbers (in string format), that I want to convert
>> to strings of a standard length of four characters:
>>
>>      e.g.,    '1'     >>> '0001'
>>               '10'    >>> '0010'
>>             '123'    >>> '0123'
>>             '4567'  >>> '4567'    // leave as is for length of 4
> [...]
>
> Perhaps something like this:
>
> String.prototype.padLeft = function(ch,len){
>      return Array(Math.max(0, len - this.length + 1)).join(ch) + this;
> }

Or

String.prototype.lpad = function(len, fchar) {
   var i = len-this.length, pad = "", f = fchar || " ";
   while(i--) { pad += f; }
   return pad+this;
};

In a completely un-scientific benchmark in Firefox and Chromium this 
solution is about twice as fast (the difference becomes less with very 
long paddings). In any case I would change your order of arguments since 
"len" is in any case a required argument, whereas "ch" can be set to a 
default value.

Gregor

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Thread

Placing 'zeros' in front of a number ? "Mel Smith" <med_cutout_syntel@aol.com> - 2012-06-21 18:37 -0600
  Re: Placing 'zeros' in front of a number ? Gene Wirchenko <genew@ocis.net> - 2012-06-21 18:59 -0700
  Re: Placing 'zeros' in front of a number ? "Michael Haufe (TNO)" <tno@thenewobjective.com> - 2012-06-21 20:18 -0700
    Re: Placing 'zeros' in front of a number ? "Mel Smith" <med_cutout_syntel@aol.com> - 2012-06-21 22:51 -0600
    Re: Placing 'zeros' in front of a number ? Gregor Kofler <usenet@gregorkofler.com> - 2012-06-22 10:34 +0200
      Re: Placing 'zeros' in front of a number ? Scott Sauyet <scott.sauyet@gmail.com> - 2012-06-22 04:49 -0700
        Re: Placing 'zeros' in front of a number ? "Mel Smith" <med_cutout_syntel@aol.com> - 2012-06-22 08:39 -0600
        Re: Placing 'zeros' in front of a number ? "Michael Haufe (TNO)" <tno@thenewobjective.com> - 2012-06-22 13:05 -0700
        Re: Placing 'zeros' in front of a number ? Gene Wirchenko <genew@ocis.net> - 2012-06-22 14:10 -0700
      Re: Placing 'zeros' in front of a number ? "Evertjan." <exxjxw.hannivoort@inter.nl.net> - 2012-06-22 22:58 +0000
        Re: Placing 'zeros' in front of a number ? Hans-Georg Michna <hans-georgNoEmailPlease@michna.com> - 2012-06-23 18:47 +0200
          Re: Placing 'zeros' in front of a number ? "Evertjan." <exxjxw.hannivoort@inter.nl.net> - 2012-06-23 21:44 +0000
            Re: Placing 'zeros' in front of a number ? "Mel Smith" <med_cutout_syntel@aol.com> - 2012-06-23 16:48 -0600
        Re: Placing 'zeros' in front of a number ? "Michael Haufe (TNO)" <tno@thenewobjective.com> - 2012-06-23 16:56 -0700
      Re: Placing 'zeros' in front of a number ? Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2012-06-23 19:47 +0200
        Re: Placing 'zeros' in front of a number ? Gregor Kofler <usenet@gregorkofler.com> - 2012-06-23 20:52 +0200
          Re: Placing 'zeros' in front of a number ? Gregor Kofler <usenet@gregorkofler.com> - 2012-06-23 21:01 +0200
        Re: Placing 'zeros' in front of a number ? "Michael Haufe (TNO)" <tno@thenewobjective.com> - 2012-06-23 17:05 -0700
          Re: Placing 'zeros' in front of a number ? Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2012-06-24 03:51 +0200
            Re: Placing 'zeros' in front of a number ? "Michael Haufe (TNO)" <tno@thenewobjective.com> - 2012-06-25 20:19 -0700
              Re: Placing 'zeros' in front of a number ? Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2012-06-26 09:04 +0200
                Re: Placing 'zeros' in front of a number ? "Michael Haufe (TNO)" <tno@thenewobjective.com> - 2012-06-26 08:32 -0700
                Re: Placing 'zeros' in front of a number ? Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2012-06-26 22:12 +0200
                Re: Placing 'zeros' in front of a number ? "Michael Haufe (TNO)" <tno@thenewobjective.com> - 2012-06-30 13:41 -0700
              Re: Placing 'zeros' in front of a number ? Dr J R Stockton <reply1226@merlyn.demon.co.uk.not.invalid> - 2012-06-27 19:34 +0100
  Re: Placing 'zeros' in front of a number ? Dr J R Stockton <reply1225@merlyn.demon.co.uk.not.invalid> - 2012-06-23 20:00 +0100

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