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Lære Negative Indexing | Indexing and Slicing
NumPy in a Nutshell
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Kursusindhold

NumPy in a Nutshell

NumPy in a Nutshell

1. Getting Started with NumPy
2. Dimensions in Arrays
3. Indexing and Slicing
4. Important Functions

book
Negative Indexing

We discussed positive indexing, but there is also negative indexing. Negative indexing starts from the end, with index -1 referring to the last element, index -2 referring to the second-to-last element, and so on.

12345
import numpy as np arr = np.array([[1, 3, 5, 7, 9], [2, 4, 6, 8, 10]]) print(arr[-1 , -1])
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This example illustrates how to retrieve a value of 10 from a given two-dimensional array using negative indexing.

The first index determines the row we choose (-1 refers to the last row), while the second index corresponds to the element we select within that row (-1 is the last one). As a result, we obtain a value of 10. Run the code above to verify it.

Opgave

Swipe to start coding

You have the following array: [[-4, 3, 1], [2, 10, -4]]. Access the value 10.

Let's give it a try. Use only negative indices.

Løsning

Switch to desktopSkift til skrivebord for at øve i den virkelige verdenFortsæt der, hvor du er, med en af nedenstående muligheder
Var alt klart?

Hvordan kan vi forbedre det?

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Sektion 3. Kapitel 5
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book
Negative Indexing

We discussed positive indexing, but there is also negative indexing. Negative indexing starts from the end, with index -1 referring to the last element, index -2 referring to the second-to-last element, and so on.

12345
import numpy as np arr = np.array([[1, 3, 5, 7, 9], [2, 4, 6, 8, 10]]) print(arr[-1 , -1])
copy

This example illustrates how to retrieve a value of 10 from a given two-dimensional array using negative indexing.

The first index determines the row we choose (-1 refers to the last row), while the second index corresponds to the element we select within that row (-1 is the last one). As a result, we obtain a value of 10. Run the code above to verify it.

Opgave

Swipe to start coding

You have the following array: [[-4, 3, 1], [2, 10, -4]]. Access the value 10.

Let's give it a try. Use only negative indices.

Løsning

Switch to desktopSkift til skrivebord for at øve i den virkelige verdenFortsæt der, hvor du er, med en af nedenstående muligheder
Var alt klart?

Hvordan kan vi forbedre det?

Tak for dine kommentarer!

Sektion 3. Kapitel 5
Switch to desktopSkift til skrivebord for at øve i den virkelige verdenFortsæt der, hvor du er, med en af nedenstående muligheder
Vi beklager, at noget gik galt. Hvad skete der?
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