NumPy: Make the length of each element 15 of a given array and the string centered / left-justified / right-justified with paddings of _

Last update on March 25 2025 12:19:39 (UTC/GMT +8 hours)

4. Adjust String Length with Padding and Justification

Write a NumPy program to make the length of each element 15 of a given array and the string centered / left-justified / right-justified with paddings of _.

Sample Solution:

Python Code:

# Importing the necessary library
import numpy as np

# Creating a NumPy array containing strings
x = np.array(['python exercises', 'PHP', 'java', 'C++'], dtype=np.str)

# Displaying the original array
print("Original Array:")
print(x)

# Applying np.char.center to center-align strings within an array
centered = np.char.center(x, 15, fillchar='_')

# Applying np.char.ljust to left-align strings within an array
left = np.char.ljust(x, 15, fillchar='_')

# Applying np.char.rjust to right-align strings within an array
right = np.char.rjust(x, 15, fillchar='_')

# Displaying the modified arrays after applying alignment functions
print("\nCentered =", centered)
print("Left =", left)
print("Right =", right) 

Sample Input:

(['python exercises', 'PHP', 'java', 'C++'], dtype=np.str)

Sample Output:

Original Array:
['python exercises' 'PHP' 'java' 'C++']

Centered = ['python exercise' '______PHP______' '______java_____' '______C++______']
Left = ['python exercise' 'PHP____________' 'java___________' 'C++____________']
Right = ['python exercise' '____________PHP' '___________java' '____________C++']

Explanation:

In the above exercise –

x1 = np.array(['python exercises', 'PHP', 'java', 'C++'], dtype=np.str): This line creates a 1-dimensional NumPy array x1 with 4 elements of string data type. The elements are ' python exercises ', 'PHP', 'Java', and 'C++'.

centered = np.char.center(x, 15, fillchar='_'): Applies the center() method from the np.char module to the x array, which centers each string in the array within a field of width 15, padded with the fill character '_' on either side as needed.

left = np.char.ljust(x, 15, fillchar='_'): Applies the ljust() method from the np.char module to the x array, which left-justifies each string in the array within a field of width 15, padded with the fill character '_' on the right as needed.

right = np.char.rjust(x, 15, fillchar='_'): Applies the rjust() method from the np.char module to the x array, which right-justifies each string in the array within a field of width 15, padded with the fill character '_' on the left as needed.

Pictorial Presentation:

For more Practice: Solve these Related Problems:

• Create a function that adjusts each string in an array to a fixed length using centered, left, and right justification with a custom padding character.
• Pad each element to a fixed length and then truncate those that exceed the limit before applying justification.
• Combine different justification methods for subgroups of elements based on a condition (e.g., even-indexed strings are centered, odd-indexed are left-justified).
• Implement a solution that verifies the final length of each element and outputs the justification type used.

Python-Numpy Code Editor:

Previous: Write a NumPy program to capitalize the first letter, lowercase, uppercase, swapcase, title-case of all the elements of a given array.
Next: Write a NumPy program to insert a space between characters of all the elements of a given array.