Chapter 05

dtype

Integer dtypes

NumPy picked an integer dtype for whole numbers. The number in the name is the bit width: int32 uses 32 bits = 4 bytes per element.

In this browser NumPy runs on 32-bit WebAssembly, so the default integer is int32. On a typical 64-bit desktop NumPy 2 would choose int64 for the same code. ArrayLab shows what NumPy really does here instead of pretending.

Try this

Remember: The dtype is shared by all elements and decides how much memory each one uses.

a = dtype shape (2, 3)

Try

Spaces or commas between values · new line = new row · blank line = new 2-D layer (3-D array).

Convert with a.astype(…)

Starting Python… (first visit downloads ≈ 15 MB, then it is cached)

Python not started

import numpy as np

a = np.array([[1, 2, 3],
              [4, 5, 6]])

result = a.astype(np.int64)
result

Output

Output appears here.