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Practice

Array Shapes, Axes, and Broadcasts

To understand how NumPy arrays behave in operations, we need to learn about shapes, axes, and broadcasting.


Shape​

Every array has a .shape, which tells you how many elements it has in each dimension.
For example, an array with 2 rows and 3 columns has a shape of (2, 3).


Axes​

An axis is a direction you can move along in an array.

  • axis=0 → down the rows (vertical)
  • axis=1 → across the columns (horizontal)

You’ll use axes when performing operations like sum(), mean(), and more.


Broadcasting​

Broadcasting is how NumPy handles arrays of different shapes during arithmetic.
It “stretches” one array so the shapes line up.

This only works when the dimensions are compatible — we’ll look at examples in the slide deck.


What’s Next​

Use the slide deck to see visual examples of shape, axes, and how broadcasting works.