From a JSON response of the format below,


I need to fetch only IDs and pass it in the next request as a list like


I was able to fetch all these IDs using a Regular Expression Extractor with the following values.

Reference Name = data ; 
Regex = "id":"(.+?)" ;
Template = $1$ ;
Match No = -1 ;

The IDs retrieved are in the following format.

data_1 = xxx
data_2 = yyy

But the IDs could be a lot, so I need an efficient way where I can use just one variable instead of using {"data":["data_1","data_2"]} and so on.

  • What code I can use if I want to get value 111
    – Vikas Ray
    Jan 12, 2023 at 5:17

1 Answer 1


You can build a single variable out of these data_1, data_2, etc. as follows:

  1. Add Beanshell PostProcessor after your Regular Expression Extractor
  2. Put the following code into the PostProcessor's "Script" area:

    StringBuilder dataBuilder = new StringBuilder();
    int ids = Integer.parseInt(vars.get("data_matchNr"));
    for (int i = 1; i <= ids; i++) {
        dataBuilder.append("\"").append(vars.get("data_" + i)).append("\"");
        if (i < ids) {
    vars.put("data", dataBuilder.toString());

Above code will concatenate all the variables prefixed with data_ coming from the Regular Expression Extractor into a single JSON array. You can refer the resulting value as ${data} where required.


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