Question

In Python

import numpy as np

Given the array a = np.array([[1, 2, 3], [10, 20, 30], [100, 200, 300]]), compute and print

1. the sums over all rows (should give [6, 60, 600])
2. the sums over all columns (the sum of he first column is 111)
3. the maximum of the array
4. the maxima over all rows
5. the mean of the sub-array formed by omitting the first row and column
6. the products over the first two columns (hint: look for an appropriate ndarray method

In Python

Answer 1

Here is a code to do so along with the output:

The codes are well commented and easy to understand, if the answer helped you please upvote and if you have any doubts please comment i will surely help. please take care of the indentation while copying the code. Check from the screenshots provided.

Code:

import numpy as np
a = np.array([[1, 2, 3], [10, 20, 30], [100, 200, 300]])

# the axis = 1 refers to the row and axis = 0 refers to columns
a.sum(axis=1)
print(f"The sum over all rows is: {a.sum(axis=1)}" )

print(f"the sums over all columns is: {a.sum(axis=0)}" )

# max without any axis value means max of entire array

print(f"The max of the array is: {a.max()}" )

# max with axis means max along all those axes

print(f"The maxima over all rows is: {a.max(axis=1)}" )

# slice the 2-d array to get a matrix with the first row
# column ommited, then call mean to find the average
subarray = a[1:3,1:3]

print(f"The mean of the sub-array formed by omitting the first row and column is: {subarray.mean()}" )

# multiply after slicing the array
product = np.multiply(a[:,0], a[:,1])
print(f"The products over the first two columns is: {product}" )