How can I get the last match in regular extracor expression in jmeter?

I would like to extract the last occurence of regular expression in Jmeter. I used Regular Extractor expression to do this, but I can't got the last occurence.

I tried this :

Regular expression: "var1":([^"]+),"var2"
Template : $1$
Match No : -1
Default value : expression_matchNr

Then in my script I used ${expression} variable

I've tested expression_matchNr but it give me the number of match.

What should I put in "Match No:" ?

Thanks in advance

Solution

If you have the following output:

expression=foo
expression_1=foo    
expression_2=bar
expression_3=**what you looking for**
expression_matchNr=3

You can use JMeter's __V function to get value of expression_3 variable

As per function's description:

For example, if one has variables A1,A2 and N=1:

${A1} - works OK
${A${N}} - does not work (nested variable reference)
${__V(A${N})} - works OK. A${N} becomes A1, and the __V function returns the value of A1

So in your case the function, returning last match no matter how many matches are will look like:

${__V(expression_${expression_matchNr})}

See How to Use JMeter Functions post series on what else can be done with functions.