setting a value in a specific position in an empty matrix using numpy python

Question

I have an issue with setting a value in an empty numpy 3D Matrix here is a simplified example of the code that I am using

import numpy as np

QMatrix = np.empty(((3,3,3))) # I do not want to use np.zero for a specific reason
QMatrix[0][0][0] = 57
print ("Position Values is " , Qmatrix[0][0][0])

This should set the value 57 @ [0][0][0] position of the matrix but when I print the matrix all I am getting is

Position Value is 5.70000000e+001

But what I want is that the value to be at as 57

any help would be appriciated. Thanks in advance

Answer 1

you must edit second line from

QMatrix = np.empty(((3,3,3)))  

to

QMatrix = np.empty(((3,3,3)), dtype=int) 

your script will be :

import numpy as np
QMatrix = np.empty(((3,3,3)), dtype=int) #QMatrix = np.empty(((3,3,3))) 
QMatrix[0][0][0] = 57

Answer 2

The default dtype of numpy array is float64 . You can verify this in your code by

import numpy as np
QMatrix = np.empty(((3,3,3)))
print QMatrix.dtype 

Outputs - dtype('float64')

So, If you want the array to be of integer type, you need to set dtype explicitly while declaring numpy array

QMatrix = np.empty(((3,3,3)),dtype='int')
print QMatrix.dtype 

Outputs - dtype('int64')

Now, if you try to assign first element of 3-D array ie QMatrix[0][0][0] = 57 it will be stored as int type not float .

.