ColdFusion: Counting to a number and repeating

coldfusion (This post is more than 2 years old.)

Ok, this is something I've done a thousand times before, but last night when I tried to get it working, it took me a few hours to get it right. I'm sure the first comment on this entry will be a comment showing how much of a bonehead I was, but darnit, I had to get this working or give up programming forever. So what's the problem? Given a set of records, I want to number them from 1 to 5 so that after 5 I go back to 1 again. Or, given 12 records, I want to see: 1,2,3,4,5,1,2,3,4,5,1,2. Simple, right?

So, I began with a simple script that I could use for testing:

<cfset records = 12> <cfset toCount = 5>

<cfloop index="x" from="1" to="#records#">

<cfoutput> Record: #x#<br/> <br/> </cfoutput> </cfloop>

Records simply represent how many iterations I'll be simulating and "toCount" represents the number I'll be counting "up" to and repeating. I then thought about the problem and came up with a formula I wrote out like this:

Take your current number, and subtract from that the whole number of sets (sets being what you are counting up).

So given 12, for example, I have 2 whole sets of 5, for a value of 10. 12-10 is 2. So here is my first take at this:

<cfset records = 12> <cfset toCount = 5>

<cfloop index="x" from="1" to="#records#">

<cfset answer = x - (toCount * (x \ toCount))> <cfoutput> Record: #x#<br/> Answer: <b>#answer#</b><br/> <br/> </cfoutput> </cfloop>

And the result:

What the hey? Every time I hit a multiple of 5 I end up with 0. Ok, that makes sense I guess. So what can I do? Just reduce my current row by one. Yeah, that's it:

<cfset records = 12> <cfset toCount = 5>

<cfloop index="x" from="1" to="#records#">

<cfset answer = x - (toCount * ((x-1) \ toCount))> <cfoutput> Record: #x#<br/> Answer: <b>#answer#</b><br/> <br/> </cfoutput> </cfloop>

And the result...

So - please - someone tell me there is a much simpler way of doing this?

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Archived Comments

Comment 1 by Will B. posted on 2/22/2011 at 7:16 PM

My right-off-the-top-of-my-head thought is two counters. Inside the loop, increment the 1-to-5 counter and if GT 5 (before using), set to 1. Quickest way I can come up with.

I'm sure there's some more complex mathematical methods, if you were so inclined.

- Will B.

Comment 2 by Raymond Camden posted on 2/22/2011 at 7:20 PM

One thing I should have added - I wanted to avoid any IF conditions (or trenary conditions).

Comment 3 by Daniel Budde posted on 2/22/2011 at 7:29 PM

I don't know that this is any more elegant of a solution, but you could place inside your loop:

<cfif x lte toCount>
<cfset answer = x />
<cfelseif x mod toCount eq 0>
<cfset answer = toCount />
<cfelse>
<cfset answer = (x mod toCount) />
</cfif>

Comment 4 by Andrea Colanicchia posted on 2/22/2011 at 7:30 PM

<cfset records = 12>
<cfset toCount = 5>

<cfloop index="x" from="1" to="#records#">

<cfset answer = ((x -1) MOD toCount) + 1>
<cfoutput>
Record: #x#<br/>
Answer: <b>#answer#</b><br/>
<br/>
</cfoutput>
</cfloop>

Not tested...

Comment 5 by Daniel Budde posted on 2/22/2011 at 7:30 PM

Dag nabbit, you posted the 'no IF' while I was in the middle of writing that out.

Comment 6 by Lance posted on 2/22/2011 at 7:30 PM

Don't know if it is any simpler. But her is an alternate method to computer answer.

<cfset answer = ((x-1) mod toCount) + 1>

Comment 7 by Joy Anderson posted on 2/22/2011 at 7:49 PM

<cfset records = 12>
<cfset toCount = 5>
<cfset answer = 1>

<cfloop index="x" from="1" to="#records#">
<cfif answer IS toCount>
<cfset answer = 1>
<cfelse>
<cfset answer = answer + 1>
</cfif>
<cfoutput>
Record: #x#<br>
Answer: #answer#<br>
<br>
</cfoutput>
</cfloop>

Comment 8 by Bob W posted on 2/22/2011 at 8:06 PM

+1 to Andrea's answer, same as what I came up with (Lance's is the same as well) - not much simpler than your answer but I think it is a bit more clear.

Comment 9 by Pat Coyne posted on 2/22/2011 at 9:39 PM

Another variant on mod. Dunno if it's any clearer.

<cfset records = 12>
<cfset toCount = 5>
<cfset n=1>
<cfloop index="x" from="1" to="#records#">

<cfoutput>

Record: #n#<br/>
<br/>
<cfif #n# mod #toCount# is 0>
<cfset n=0>
</cfif>
</cfoutput>
<cfset n=#n#+1>
</cfloop>

Comment 10 by Phillip Senn posted on 2/22/2011 at 11:50 PM

+1 Andrea.
Here it is in Microsoft SQL Server, where the percent sign is the MOD operator:

DECLARE @myTable TABLE(
TableID Int Identity
,Answer Int
)
INSERT INTO @myTable(Answer) VALUES(1)
INSERT INTO @myTable(Answer) VALUES(2)
INSERT INTO @myTable(Answer) VALUES(3)
INSERT INTO @myTable(Answer) VALUES(4)
INSERT INTO @myTable(Answer) VALUES(5)
INSERT INTO @myTable(Answer) VALUES(6)
INSERT INTO @myTable(Answer) VALUES(7)
INSERT INTO @myTable(Answer) VALUES(8)
INSERT INTO @myTable(Answer) VALUES(9)
INSERT INTO @myTable(Answer) VALUES(10)
INSERT INTO @myTable(Answer) VALUES(11)
INSERT INTO @myTable(Answer) VALUES(12)

SELECT *
,((Answer-1) % 5+1) AS ModAnswer
FROM @myTable
order by Answer

Comment 11 by Shrainik posted on 2/23/2011 at 12:43 PM

x = 11;
for(var i=0;i<=x;i++){
output( i%5 + 1 );
}

Comment 12 by Jonathan posted on 2/25/2011 at 12:28 PM

<cfset records = 12>
<cfset toCount = 5>

<cfloop index="x" from="1" to="#records#">
<cfset answer = iif(x mod toCount,x mod toCount,toCount)>
<cfoutput>
Record: #x#<br/>
Answer: <b>#answer#</b><br/>
<br/>
</cfoutput>
</cfloop>