How to use API of BTC.com I'd like to get some information(BTC's difficulty, hash rate).
I think I can get that from api of BTC.com, and I checked github of btccom, but I can't mount api with python. 

How Can I use btccom api(v3)?
maybe for the first time, I need to install something on terminal(mac).
It's like a [pip insall ***].

Than you
BTC.com APIs are Web APIs. This means you can use them by making HTTP requests (GET/POST requests).

Like all online APIs, you can access them through whatever program/script you want, provided they are able to make HTTP requests and handle the answers.
Requests/responses are usually encoded using the JSON format.

You can find a good introduction here.

You can choose your favorite language. However, since data is in JSON format, I would suggest to use either Javascript or Python.
In Python you can use the 'request' package. Here you can find a quick introduction.

In Javascript you have the 'request' library.
I wrote a generic lib to make Web API requests: https://github.com/frz-dev/webapi.js/blob/master/webapi.js