Jmeter does not save variable with variable name <variable-name>_1

Question

I have a loop controller in my test plan with a counter called fileNumber.

I also have a groovy script which fetches keys and uploadIds from the response of an API call. This is the script I have:

def uploadId = vars.get("uploadId");
def fileKey = vars.get("key");
def fileNumber = vars.get("fileNumber");

if (!uploadId.isEmpty() && !fileKey.isEmpty()) {
    vars.put("key_" + fileNumber, fileKey);
    vars.put("uploadId_" + fileNumber, uploadId);
}

I expected this to create variables for key as key_1, key_2...key_5. What I get, is that key_1 is stored correctly in the first call of the API in the loop:

But in the 2nd to 5th iterations of the loop, the variables for the 2nd to 5th values are stored.

The variable key_1 is not set at all.

When I give the start value as 0 and maximum value as 4, then I get key_0, key_2, key_3, key_4. But still no key_1

Why is this happening?

When I changed the variable name to fileKey, it worked. I'm assuming it's because key_1 is saved somewhere but I have not defined key_1 as a variable elsewhere

Answer 1

You have this condition:

if (!uploadId.isEmpty() && !fileKey.isEmpty()) {

please check the values of the given variables, it might be the case one of them is not set.

Use Debug Sampler to see which variables are defined in each loop.

Also it is not required to define the counter, Loop Controller has built-in counter and exposes variable called __jm__Loop Controller__idx which holds current iteration number