Return a boolean array which is True where the string element in array ends with suffix in Python

To return a boolean array which is True where the string element in array ends with a specific suffix, use the numpy.char.endswith() method. This function performs vectorized string operations on NumPy string arrays, checking each element for the specified suffix.

Syntax

numpy.char.endswith(a, suffix, start=0, end=None)

Parameters

a ? Input array of strings

suffix ? String suffix to check for

start ? (Optional) Start position for checking

end ? (Optional) End position for checking

Basic Example

Let's create a string array and check which elements end with a specific suffix ?

import numpy as np

# Create array of strings
names = np.array(['KATIE', 'JOHN', 'KATE', 'AmY', 'BRADley'])

print("Array:")
print(names)

# Check which names end with 'E'
result = np.char.endswith(names, 'E')
print("\nElements ending with 'E':")
print(result)

Array:
['KATIE' 'JOHN' 'KATE' 'AmY' 'BRADley']

Elements ending with 'E':
[ True False  True False False]

Multiple Suffix Examples

You can check for different suffixes and combine results ?

import numpy as np

words = np.array(['running', 'walked', 'jumping', 'played', 'swimming'])

# Check for different suffixes
ends_with_ing = np.char.endswith(words, 'ing')
ends_with_ed = np.char.endswith(words, 'ed')

print("Words:", words)
print("Ends with 'ing':", ends_with_ing)
print("Ends with 'ed':", ends_with_ed)

# Words ending with either suffix
either_suffix = ends_with_ing | ends_with_ed
print("Ends with 'ing' OR 'ed':", either_suffix)

Words: ['running' 'walked' 'jumping' 'played' 'swimming']
Ends with 'ing': [ True False  True False  True]
Ends with 'ed': [False  True False  True False]
Ends with 'ing' OR 'ed': [ True  True  True  True  True]

Case-Sensitive Checking

The endswith() method is case-sensitive. Here's how to handle different cases ?

import numpy as np

mixed_case = np.array(['Apple', 'BANANA', 'orange', 'Grape'])

# Case-sensitive check
print("Original array:", mixed_case)
print("Ends with 'e':", np.char.endswith(mixed_case, 'e'))
print("Ends with 'E':", np.char.endswith(mixed_case, 'E'))

# Convert to lowercase first for case-insensitive check
lowercase_array = np.char.lower(mixed_case)
print("Case-insensitive check for 'e':", np.char.endswith(lowercase_array, 'e'))

Original array: ['Apple' 'BANANA' 'orange' 'Grape']
Ends with 'e': [ True False  True  True]
Ends with 'E': [False False False False]
Case-insensitive check for 'e': [ True False  True  True]

Practical Use Case

Filter array elements based on suffix matching ?

import numpy as np

files = np.array(['document.pdf', 'image.jpg', 'data.csv', 'photo.png', 'report.pdf'])

# Find all PDF files
is_pdf = np.char.endswith(files, '.pdf')
pdf_files = files[is_pdf]

print("All files:", files)
print("PDF files only:", pdf_files)
print("Number of PDF files:", np.sum(is_pdf))

All files: ['document.pdf' 'image.jpg' 'data.csv' 'photo.png' 'report.pdf']
PDF files only: ['document.pdf' 'report.pdf']
Number of PDF files: 2

Conclusion

The numpy.char.endswith() method efficiently checks string suffixes across entire arrays, returning boolean arrays for filtering or conditional operations. It's particularly useful for file processing and text analysis tasks.