Count Occurences of Substring in a String

Get Started
1

Hello all,

Just wondering if there is a CF function that will count the occurrences of a substring within a string. Can’t check Adobe LiveDocs right now because the server is down!

Thanks.

2

Oh boo, I spelled “occurrences” wrong in the title and I can’t edit it! Just thought I’d point that out before someone else does :slight_smile: .

3 

<cfset occurrences
    = Len(Replace(string,substring,'','all'))
      / Len(substring) >
4

p.s. don’t never use adobe’s web site, it’s slower than cold glue, way too much stoopid “rich content” and online paper for my liking

i use this – http://www.cfquickdocs.com/

5

rudy? maybe im not following what it is you were trying to do there, but I don’t think that is what he is after.

Using this code:


<cfset variables.string = "the quick brown fox jumped over the red bridge" />
<cfset variables.substring = "the" />

<cfset occurrences = Len(Replace(variables.string,variables.substring,'','all')) / Len(variables.substring) >
    
<cfdump var="#occurrences#">

which should be counting the number of times the word “the” occurres, I get 13.3333, which I don’t think is correct. Or am I misusing your code?

I would use a function like this:


<cffunction name="countOccurrences" access="public" returntype="numeric" required="true">
    <cfargument name="string" type="string" required="True" />
    <cfargument name="subString" type="string" required="True" />
    
    <cfset VAR position = findNoCase(arguments.substring,arguments.string,1) />
    <cfset VAR count = 0 />
    
    <cfif len(trim(arguments.substring))>
        <cfloop condition="position NEQ 0">
            <cfset count = count + 1 />
            <cfset position = findNoCase(arguments.substring,arguments.string, position + len(trim(arguments.substring))) />
        </cfloop>
    <cfelse>
        <cfreturn 0 />
    </cfif>

<cfreturn count />
</cffunction>

then you can just call it whenever you need, pass it the full string, pass it the string you are looking for, and it returns a number of how many times it occurs.

6

aaargggggghhhhhhhhh my bad

<cfset occurrences
   = ( Len(string) -
       Len(Replace(string,substring,'','all'))
     ) / Len(substring) >

still a lot simpler than a loop, eh

(my experience with databases has taught me that any time you are doing anything in a loop, there’s probably a more efficient way)

:slight_smile:

7

I had a feeling that you just botched the code, in fact, I think you have given that same example out here before and I remember being impressed.

Yes, this will work, except there is a good chance you want replaceNoCase() instead of just replace(), depending on what you are doing.

bows to rudy’s algorithm genius

8

Yeah, I was wondering if I was just crazy and couldn’t get the code to work correctly :).

I ended up just writing my own function and it turned up basically like what rynoguill wrote. So, thanks for the responses!

9

please, please, oh do please try my solution, it works, i tested it