numpy: filling a subset of array

Question

I have a numpy array of dimension 3x3 i.e. it has a total of 9 elements. I have 8 values that I would like to set and the value at location (2, 2) will always be 1. I can do it individually as follows:

import numpy as np
def set(coefs):
    a = np.zeros(3,3)
    a[0, 0] = coefs[0]
    a[0, 1] = coefs[1]
    a[0, 2] = coefs[2]
    a[1, 0] = coefs[3]

    ...
    a[2, 2] = 1

However, I was wondering if there is a more concise and general way to fill those 8 values.

Alex Martelli · Accepted Answer · 2015-02-23 00:59:59Z

3

Seems like

np.array(coefs[:8]+[1]).reshape((3,3))

should do exactly what you require, right?

answered Feb 23, 2015 at 0:59

Alex Martelli

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4 Comments

Luca Over a year ago

That did the trick! Thanks. I am still getting used to these funky python addressing!

Alex Martelli Over a year ago

Ciao @Luca, this is more numpy 2-d addressing than Python addressing per se:-). Anyway, please make sure to accept this answer (click on the checkmark-shaped outline to the left of the A) once enough time has elapsed for acceptance (I can never recall how long you must wait before accepting depending on your rep:-).

Luca Over a year ago

I have to wait 10 minutes before accepting the answer ;-) You were too fast :)

Alex Martelli Over a year ago

@Luca, scusami, this community's so awesome that unless I answer at once I'll never get accepts!-)

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