How to print array elements within a given range using Numpy?

In NumPy, you can print array elements within a specific range using several methods. The most common approaches are numpy.where() with numpy.logical_and(), boolean indexing, and conditional filtering.

Using numpy.where() with logical_and()

The numpy.where() function returns the indices of elements that meet a condition ?

import numpy as np

arr = np.array([1, 3, 5, 7, 10, 2, 4, 6, 8, 10, 36])
print("Original Array:")
print(arr)

# Find indices of elements between 4 and 20 (inclusive)
indices = np.where(np.logical_and(arr >= 4, arr <= 20))
print("\nIndices of elements in range [4, 20]:")
print(indices[0])

# Get the actual elements using the indices
elements_in_range = arr[indices]
print("\nElements in range [4, 20]:")
print(elements_in_range)

Original Array:
[ 1  3  5  7 10  2  4  6  8 10 36]

Indices of elements in range [4, 20]:
[2 3 4 6 7 8 9]

Elements in range [4, 20]:
[ 5  7 10  4  6  8 10]

Using Boolean Indexing

Boolean indexing provides a more direct way to filter elements ?

import numpy as np

arr = np.array([1, 3, 5, 7, 10, 2, 4, 6, 8, 10, 36])
print("Original Array:")
print(arr)

# Create boolean mask for elements in range [4, 20]
mask = (arr >= 4) & (arr <= 20)
print("\nBoolean mask:")
print(mask)

# Extract elements using the mask
filtered_elements = arr[mask]
print("\nElements in range [4, 20]:")
print(filtered_elements)

Original Array:
[ 1  3  5  7 10  2  4  6  8 10 36]

Boolean mask:
[False False  True  True  True False  True  True  True  True False]

Elements in range [4, 20]:
[ 5  7 10  4  6  8 10]

Using numpy.extract()

The numpy.extract() function provides another approach for conditional filtering ?

import numpy as np

arr = np.array([1, 3, 5, 7, 10, 2, 4, 6, 8, 10, 36])
print("Original Array:")
print(arr)

# Extract elements in range [4, 20]
condition = (arr >= 4) & (arr <= 20)
filtered_elements = np.extract(condition, arr)

print("\nElements in range [4, 20]:")
print(filtered_elements)

Original Array:
[ 1  3  5  7 10  2  4  6  8 10 36]

Elements in range [4, 20]:
[ 5  7 10  4  6  8 10]

Comparison of Methods

Conclusion

Boolean indexing with (arr >= min_val) & (arr is the most efficient and readable method. Use np.where() when you need both indices and values.