w3resource

NumPy: Create a vector with values ​​from 0 to 20 and change the sign of the numbers in the range from 9 to 15

NumPy: Basic Exercise-22 with Solution

Write a NumPy program to create a vector with values ​​from 0 to 20 and change the sign of the numbers in the range from 9 to 15.

Sample Solution :

Python Code :

import numpy as np
x = np.arange(20)
print("Original vector:")
print(x)
print("After changing the sign of the numbers in the range from 9 to 15:")
x[(x >= 9) & (x <= 15)] *= -1
print(x)

Sample Output:

Original vector:
[ 0  1  2  3  4  5  6  7  8  9 10 11 12 13 14 15 16 17 18 19]
After changing the sign of the numbers in the range from 9 to 15:
[  0   1   2   3   4   5   6   7   8  -9 -10 -11 -12 -13 -14 -15  16  17
  18  19]                         

Pictorial Presentation:

NumPy: Create a vector with values ​​from 0 to 20 and change the sign of the numbers in the range from 9 to 15.

Python Code Editor:


Have another way to solve this solution? Contribute your code (and comments) through Disqus.

Previous: Write a NumPy program to create a vector of length 10 with values ​​evenly distributed between 5 and 50.
Next: Write a NumPy program to create a vector of length 5 filled with arbitrary integers from 0 to 10.

What is the difficulty level of this exercise?

Test your Python skills with w3resource's quiz



Python: Tips of the Day

Merges two or more lists into a list of lists, combining elements from each of the input lists based on their positions

Example:

def tips_merge(*args, fill_value=None):
  max_length = max([len(lst) for lst in args])
  result = []
  for i in range(max_length):
    result.append([
      args[k][i] if i < len(args[k])
	  else fill_value for k in range(len(args))
    ])
  return result
print(tips_merge(['x', 'y'], [1, 2], [True, False])) 
print(tips_merge(['x'], [1, 2], [True, False])) 
print(tips_merge(['x'], [1, 2], [True, False], fill_value = '_')) 

Output:

[['x', 1, True], ['y', 2, False]]
[['x', 1, True], [None, 2, False]]
[['x', 1, True], ['_', 2, False]]