Modules, Files and JSON on kodkod | Intro Course

Modules: Why We Split into Files, import, from and as

Mon, 01 Jan 0001 00:00:00 +0000

What will we learn?

What a Module is.
Why a project is split into several files.
Three forms of importing: import, from ... import, as.
What exactly happens when Python imports a file.

Why do we need this?

We already used modules: import os, import logging, import socket. Today we will write our own.

Packages, init.py and if name == "main"

Mon, 01 Jan 0001 00:00:00 +0000

What will we learn?

Package — a folder that contains modules.
The file __init__.py and its role.
Importing from inside a Package.
The special variable __name__, and the pattern if __name__ == "__main__":.

Why do we need this?

When there are 3 modules, they can sit in the same folder. When there are 30, you need folders: everything related to users in one folder, everything related to payments in another. That is how all real projects are built, and also all the libraries you will install (FastAPI is a huge Package with dozens of sub-Packages).

Working with Text Files: open, with, Reading and Writing

Mon, 01 Jan 0001 00:00:00 +0000

What will we learn?

Opening a file with open and opening modes.
Why a file must be closed, and how with does it automatically.
Reading: the whole file, line by line.
Writing and appending.
A robust path, one that does not depend on where you run from (we promised in the topic on the computer, the operating system and the network!).

Why do we need this?

The topic on the computer, the operating system and the network: “everything in RAM disappears when the program ends”. Files are the basic way to save information on Storage: settings, reports, history, data for import and export. The counter that always went back to 1 in memory_test.py? Today we will make it survive between runs.

JSON: Reading, Writing and Saving Data

Mon, 01 Jan 0001 00:00:00 +0000

What will we learn?

What JSON is and what it looks like.
How JSON matches Python’s dict and list.
Saving to a file and loading from it.
Converting between a JSON string and data.

Why do we need this?

In the previous lesson we saved text, and for that we invented a “format” of our own: Dana,90 on every line. Now suppose every student has a list of grades, an address with a city and a street, and an is_active flag. How do you save that in a line of text? Everyone will invent a different format, and we will have to write complicated parsing code.

Modules, Files and JSON on kodkod | Intro Course

Modules: Why We Split into Files, import, from and as

What will we learn?

Why do we need this?

Packages, __init__.py and if __name__ == "__main__"

What will we learn?

Why do we need this?

Working with Text Files: open, with, Reading and Writing

What will we learn?

Why do we need this?

JSON: Reading, Writing and Saving Data

What will we learn?

Why do we need this?

Packages, init.py and if name == "main"