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What an import line means

P39.reading-code.02 · Audience: guest, language-pro, it-ml · Prerequisites: What a rung is, versus a notebook

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Open almost any Python file — including the ones in every other discipline here — and the first line is import something. It looks like a password you were never given. It is not. This module demystifies the one line that starts everything else.

ⓘ Concept: import borrows a ready-made tool

import means "borrow a tool someone else already wrote, so I don't have to build it myself". Python ships with ready-made toolboxes; an import line opens one. After import math you can use its tools by writing math. and the tool's name — for example math.sqrt(9) for a square root. You are not memorising magic; you are borrowing.

Why it matters — The import line is the single most common thing a beginner sees and cannot explain. Naming it removes the feeling that code is written in a secret language.

The everyday comparison

You do not forge your own scissors before cutting paper — you take a pair from the drawer. import is opening the drawer. math is one drawer that comes with Python; there are many others, and later you will borrow tools for dates, for text, for tables. The line that once looked cryptic just says "pass me that tool".

Your turn

The rung opens the math toolbox and uses math.sqrt. You will let that borrowed tool work out a square root for you — no arithmetic by hand — and say, in plain words, what an import line actually does.

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🎓 Practice ladder

1 graded rung · ~4 min

One short rung. Use the borrowed tool, answer one plain question, press Run. This is the last step of the "you are not lost" pillar.

Explorer rung — borrow a tool with import

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