Please note, this is a STATIC archive of website www.w3resource.com from 19 Jul 2022, cach3.com does not collect or store any user information, there is no "phishing" involved.
w3resource

NumPy: Transform a given array

NumPy: Basic Exercise-51 with Solution

Write a NumPy program to create a new array of given shape (5,6) and type, filled with zeros.
Change the said array in the following format:

Given array:
[[0 0 0 0 0 0]
[0 0 0 0 0 0]
[0 0 0 0 0 0]
[0 0 0 0 0 0]
[0 0 0 0 0 0]]
New array:
[[3 0 3 0 3 0]
[7 0 7 0 7 0]
[3 0 3 0 3 0]
[7 0 7 0 7 0]
[3 0 3 0 3 0]]

Sample Solution:

Python Code :

import numpy as np
nums = np.zeros(shape=(5, 6), dtype='int')
print("Original array:")
print(nums)
nums[::2, ::2] = 3
nums[1::2, ::2] = 7
print("\nNew array:")
print(nums)

Sample Output:

Original array:
[[0 0 0 0 0 0]
 [0 0 0 0 0 0]
 [0 0 0 0 0 0]
 [0 0 0 0 0 0]
 [0 0 0 0 0 0]]

New array:
[[3 0 3 0 3 0]
 [7 0 7 0 7 0]
 [3 0 3 0 3 0]
 [7 0 7 0 7 0]
 [3 0 3 0 3 0]]

Python-Numpy Code Editor:

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

Previous: Write a NumPy program to create a 4x4 array with random values, now create a new array from the said array swapping first and last rows.
Next: Write a NumPy program to sort a given array by row and column in ascending order.

What is the difficulty level of this exercise?

Test your Programming skills with w3resource's quiz.



Python: Tips of the Day

Find current directory and file's directory:

To get the full path to the directory a Python file is contained in, write this in that file:

import os 
dir_path = os.path.dirname(os.path.realpath(__file__))

(Note that the incantation above won't work if you've already used os.chdir() to change your current working directory, since the value of the __file__ constant is relative to the current working directory and is not changed by an os.chdir() call.)

To get the current working directory use

import os
cwd = os.getcwd()

Documentation references for the modules, constants and functions used above:

  • The os and os.path modules.
  • The __file__ constant
  • os.path.realpath(path) (returns "the canonical path of the specified filename, eliminating any symbolic links encountered in the path")
  • os.path.dirname(path) (returns "the directory name of pathname path")
  • os.getcwd() (returns "a string representing the current working directory")
  • os.chdir(path) ("change the current working directory to path")

Ref: https://bit.ly/3fy0R6m