NumPy: Test whether specified values are present in an array

Last update on August 29 2025 12:46:45 (UTC/GMT +8 hours)

Check Values Present in Array

Write a NumPy program to test if specified values are present in an array.

Pictorial Presentation:

Sample Solution:

Python Code:

# Importing the NumPy library with an alias 'np'
import numpy as np

# Creating a 2x3 NumPy array 'x' with specific float values
x = np.array([[1.12, 2.0, 3.45], [2.33, 5.12, 6.0]], float)

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

# Checking if 2 is present in the array 'x'
print(2 in x)

# Checking if 0 is present in the array 'x'
print(0 in x)

# Checking if 6 is present in the array 'x'
print(6 in x)

# Checking if 2.3 is present in the array 'x'
print(2.3 in x)

# Checking if 5.12 is present in the array 'x'
print(5.12 in x) 

Sample Output:

Original array:                                                        
[[ 1.12  2.    3.45]                                                   
 [ 2.33  5.12  6.  ]]                                                  
True                                                                   
False                                                                  
True                                                                   
False                                                                  
True    

Explanation:

In the above exercise -

‘x = np.array([[1.12, 2.0, 3.45], [2.33, 5.12, 6.0]], float)’ creates a 2D NumPy array x with the specified floating-point values.

The following statements use the in operator to check if the specified values are present in the array x:

• print(2 in x): Checks if 2 is present in the array. Prints True because 2.0 is present.
• print(0 in x): Checks if 0 is present in the array. Prints False because 0 is not present.
• print(6 in x): Checks if 6 is present in the array. Prints True because 6.0 is present.
• print(2.3 in x): Checks if 2.3 is present in the array. Prints False because 2.3 is not present.
• print(5.12 in x): Checks if 5.12 is present in the array. Prints True because 5.12 is present.

For more Practice: Solve these Related Problems:

• Write a NumPy program to test if specified values exist in an array using np.isin.
• Create a function that takes an array and a list of target values, returning a boolean array for membership.
• Verify the presence of values by comparing the output of np.in1d with a custom iteration method.
• Use logical operations to check if multiple specific values are simultaneously present in a given array.

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