Broadcast value across field in NumPy Structured array

Last update on April 30 2025 12:54:30 (UTC/GMT +8 hours)

20. Broadcast Value across 'Height' Field

Broadcasting with Structured Arrays:

Write a NumPy program to broadcast a value (e.g., set all 'height' values to 6.0) across the 'height' field in the structured array created with fields for 'name' (string), 'age' (integer), and 'height' (float).

Sample Solution:

Python Code:

import numpy as np

# Define the data type for the structured array
dtype = [('name', 'U10'), ('age', 'i4'), ('height', 'f4')]

# Create the structured array with sample data
structured_array = np.array([
    ('Lehi Piero', 25, 5.5),
    ('Albin Achan', 30, 5.8),
    ('Zerach Hava', 35, 6.1),
    ('Edmund Tereza', 40, 5.9),
    ('Laura Felinus', 28, 5.7)
], dtype=dtype)

print("Original structured array: ",structured_array)

# Broadcast a value (e.g., set all 'height' values to 6.0) across the 'height' field
structured_array['height'] = 6.0

# Print the updated structured array
print("\nStructured Array with all 'height' values set to 6.0:")
print(structured_array)

Output:

Original structured array:  [('Lehi Piero', 25, 5.5) ('Albin Acha', 30, 5.8) ('Zerach Hav', 35, 6.1)
 ('Edmund Ter', 40, 5.9) ('Laura Feli', 28, 5.7)]

Structured Array with all 'height' values set to 6.0:
[('Lehi Piero', 25, 6.) ('Albin Acha', 30, 6.) ('Zerach Hav', 35, 6.)
 ('Edmund Ter', 40, 6.) ('Laura Feli', 28, 6.)]

Explanation:

Import Libraries:

Imported numpy as "np" for array creation and manipulation.

Define Data Type:

Define the data type for the structured array using a list of tuples. Each tuple specifies a field name and its corresponding data type. The data types are:

'U10' for a string of up to 10 characters.
'i4' for a 4-byte integer.
'f4' for a 4-byte float.

Create a Structured Array:

Created the structured array using np.array(), providing sample data for five individuals. Each individual is represented as a tuple with values for 'name', 'age', and 'height'.

Broadcast value:

Broadcast a value by setting all 'height' field values to 6.0 using structured_array['height'] = 6.0.

Print the updated structured array to verify that all 'height' values have been set to 6.0.

For more Practice: Solve these Related Problems:

Write a Numpy program to broadcast a new value (e.g., 6.0) to update all entries in the 'height' field of a structured array.
Write a Numpy program to set the 'height' field of all records to a computed value using broadcasting and then verify the update.
Write a Numpy program to replace the 'height' values with a constant via broadcasting and then compare the result with manual assignment.
Write a Numpy program to use broadcasting to update the 'height' field conditionally, setting all heights below a threshold to a fixed value.

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