Why environment's key must equal data file key

Hi Team, I have a question.
Why environment variable’s key must equal data file key.
e.g. A CSV file(key name is phone, values like 1 2 3……),Request url maybe like http://127.0.0.1/{{phone}}, environment variable’s key name is phone , value is data.phone , it’s OK, because all key named ‘phone’.
But when I change the environment variable’s key name from phone to mobile, value is data.phone, Request url maybe like http://127.0.0.1/{{mobile}}.Now it’s wrong…

I want to know why.
I think when I use {{key1}}, the variable’s key name must be key1, if the data file’s key name is key2, I set the variable’s value=data.key2, but it’s wrong…key1 must equal key2…

waiting for your reply:grinning:

ORZ…
Now I find when runner use data file,request use {{key}} is the data file’s key…not the environment variable’s key…so the {{key}} must equal the data file’s key
so, I don’t need to set the environment variable…it will be replaced…

T_T