R - Create JSON for Adobe Analytics API call - define object conditionally

Question

I have following code to create a JSON for making a call to Adobe Analytics API (method segment.save)

item <- 
  list(definition = list(
    container = list (
      type = "hits",
      operator = "or",
      rules=I(list(
        list(value= "test1 test2",
             operator = "contains_any",
             element = "page")))

    )
  ),
  owner="test",
  reportSuiteID="test",
  description="API Generated Segment",
  name="test segment"
  )

Once prettyfied and auto-unboxed, the result is:

> jsonlite::toJSON(item, pretty = T, auto_unbox= T) 
{
  "definition": {
    "container": {
      "type": "hits",
      "operator": "or",
      "rules": [
        {
          "value": "test1 test2",
          "operator": "contains_any",
          "element": "page"
        }
      ]
    }
  },
  "owner": "test",
  "reportSuiteID": "test",
  "description": "API Generated Segment",
  "name": "test segment"
} 

Good for creating new segments, but not so good for editing them

The JSON structure is valid, as I am able to create the new segment. However, I would like to check if the segment already exists (using f.i. the GetSegments() function from randyzwitch RSiteCatalyst package and check if name coincides already with a created segment). If the segment already exists, I want to pass the id to the API call, which is the method used for editing already existing segments. It should then look like:

 > jsonlite::toJSON(item, pretty = T, auto_unbox= T) 
{
  "definition": {
    ... 
  },
  "owner": "test",
  "reportSuiteID": "test",
  "description": "API Generated Segment",
  "name": "test segment",
  "id": "s1982XXXXXXXXX_XXXXX_XXXXX",
} 

It is possible to make an if alike statement within the list() definition provided in the first piece of code? I would like to reach a solution that does not need an if statement that checks if segmentID exists and, depending on it, generates a call with id or a call without id.

Answer 1

Once a "JSON alike structure" is created using list function:

 item <- 
      list(definition = list(
        container = list (
          type = "hits",
          operator = "or",
          rules=I(list(
            list(value= "test1 test2",
                 operator = "contains_any",
                 element = "page")))

        )
      ),
      owner="test",
      reportSuiteID="test",
      description="API Generated Segment",
      name="test segment"
      )

We can push new elements to this list using the needed conditions. For example, if we have our segment IDs in a dataframe with name segments, we can push this ID to item this way:

if (!is.na(segments$segmentID[i])) {
  item <- c(item, id=segments$segmentID[i])
}