Using Rand() To Generate Random Times In ColdFusion

Posted April 30, 2007 at 1:13 PM

Tags: ColdFusion

I was on the way to the bathroom (the Tea has to go somewhere) when this popped into my head: Since dates in ColdFusion are represented as floating numbers and the decimal represents the time of day, you can use ColdFusion's Rand() function to generate random times. Think about it; since Rand() gets a value that is between 0 and 1, this can be thought of as between 12:00 AM one day and 12:00 AM the next (1 = 12:00 AM of the next day).

Here's a little test:

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  • <cfloop
  • index="intI"
  • from="1"
  • to="10"
  • step="1">
  •  
  • #TimeFormat( Rand(), "hh:mm TT" )#
  •  
  • </cfloop>

Running the above code, we get:

09:46 PM
07:10 AM
07:48 AM
07:54 AM
03:20 PM
03:44 AM
08:23 PM
04:07 AM
10:05 PM
01:46 PM

Well anyway, this is really not that useful, but you never know. You might come up against a situation where picking random times is critical?? Good to know that this can easily be done.

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Reader Comments

Dmitriy Goltseker
Apr 30, 2007 at 2:55 PM // reply »
27 Comments
25 Points

We actually use this format for searching. It helps us a great deal.


Ben Nadel
Apr 30, 2007 at 3:00 PM // reply »
6,516 Comments
25,763 Points

What do you mean exactly? This sounds cool.


Dmitriy Goltseker
Apr 30, 2007 at 3:27 PM // reply »
27 Comments
25 Points

Here's an example:
"Service on between" and then you specify 2 dates
"Service on between" 1/12/2003 and 04/01/2007.

First of all you need to compare each value to the values stored in the db. Then you need to compare that 1/12/2003 is in between the dates stored in the db; same thing for 04/01/2007; and then you need to do the same for all the dates between 1/12/2003 and 04/01/2007. If you do date comparison, it will take a long time to get results. I'm not even talking about if you have a lot of results and the date ranges are bigger. Now, if you convert the dates to decimal point numbers, you will be comparing the numbers and not the dates, which is much faster and more efficient.


Ben Nadel
Apr 30, 2007 at 4:20 PM // reply »
6,516 Comments
25,763 Points

Ahhh, I see what you are saying. But, do you mean you actually store the value in a DateTime field in the database? Or is a float/decimal field type?


Dmitriy Goltseker
Apr 30, 2007 at 4:25 PM // reply »
27 Comments
25 Points

store as date/time


Ben Nadel
Apr 30, 2007 at 5:30 PM // reply »
6,516 Comments
25,763 Points

I gotcha. Cool stuff.


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