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The following functions are used to perform vectorized string operations on arrays with dtype of numpy.string_ or numpy.unicode_. They are based on the standard string functions in Python's built-in library.

These functions are defined in the character array class (numpy.char).

Function	Description
add()	Concatenates strings element-wise from two arrays
multiply()	Returns a string after element-wise multiple concatenation
center()	Centers a string
capitalize()	Converts the first character of the string to uppercase
title()	Converts the first character of each word in the string to uppercase
lower()	Converts array elements to lowercase
upper()	Converts array elements to uppercase
split()	Splits a string by a specified delimiter and returns an array of lists
splitlines()	Returns a list of lines in the elements, split by line breaks
strip()	Removes specific characters from the beginning or end of an element
join()	Joins elements in an array by a specified delimiter
replace()	Replaces all occurrences of a substring in a string with a new string
decode()	Calls str.decode on each array element sequentially
encode()	Calls str.encode on each array element sequentially

numpy.char.add()

The numpy.char.add() function concatenates strings element-wise from two arrays.

Example

import numpy as np

print('Concatenating two strings:')
print(np.char.add(['hello'], [' xyz']))
print('n')
print('Concatenation example:')
print(np.char.add(['hello', 'hi'], [' abc', ' xyz']))

The output is:

Concatenating two strings:
['hello xyz']

Concatenation example:
['hello abc' 'hi xyz']

numpy.char.multiply()

The numpy.char.multiply() function performs multiple concatenations.

Example

import numpy as np

print(np.char.multiply('Tutorial ', 3))

The output is:

Tutorial Tutorial Tutorial 

numpy.char.center()

The numpy.char.center() function is used to center a string, padding it with a specified character on the left and right.

Example

import numpy as np

print(np.char.center('Tutorial', 20, fillchar='*'))

The output is:

******* Tutorial ******* 

numpy.char.capitalize()

The numpy.char.capitalize() function converts the first character of the string to uppercase:

Example

import numpy as np

print(np.char.capitalize('tutorial'))

The output is:

Tutorial

numpy.char.title()

The numpy.char.title() function converts the first character of each word in the string to uppercase:

Example

import numpy as np

print(np.char.title('i like tutorial'))

The output is:

I Like Tutorial

numpy.char.lower()

The numpy.char.lower() function converts each element of the array to lowercase. It calls str.lower on each element.

Example

import numpy as np

print(np.char.lower(['TUTORIAL', 'GOOGLE']))
print(np.char.lower('TUTORIAL'))

The output is:

['tutorial' 'google']
tutorial

numpy.char.upper()

The numpy.char.upper() function converts each element of the array to uppercase. It calls str.upper on each element.

Example

import numpy as np

print(np.char.upper(['tutorial', 'google']))
print(np.char.upper('tutorial'))

The output is:

['TUTORIAL' 'GOOGLE']
TUTORIAL

numpy.char.split()

The numpy.char.split() function splits a string by a specified delimiter and returns an array. By default, the delimiter is a space.

Example

import numpy as np

print(np.char.split('i like tutorial?'))
print(np.char.split('www.', sep='.'))

The output is:

['i', 'like', 'tutorial?']
['www', 'tutorial', 'com']

numpy.char.splitlines()

The numpy.char.splitlines() function splits a string by line breaks and returns an array.

Example

import numpy as np

print(np.char.splitlines('in like tutorial?'))
print(np.char.splitlines('ir like tutorial?'))

The output is:

['i', 'like tutorial?']
['i', 'like tutorial?']

n, r, and rn can all be used as line breaks.

numpy.char.strip()

The numpy.char.strip() function is used to remove specific characters from the beginning or end.

Example

import numpy as np

print(np.char.strip('ashok atutoriala', 'a'))
print(np.char.strip(['atutoriala', 'admin', 'java'], 'a'))

The output is:

shok atutorial
['tutorial' 'dmin' 'jav']

numpy.char.join()

The numpy.char.join() function joins elements or strings in an array by a specified delimiter.

Example

import numpy as np

print(np.char.join(':', 'tutorial'))
print(np.char.join([':', '-'], ['tutorial', 'google']))

The output is:

r:u:n:o:o:b
['r:u:n:o:o:b' 'g-o-o-g-l-e']

numpy.char.replace()

The numpy.char.replace() function replaces all occurrences of a substring in a string with a new string.

Example

import numpy as np

print(np.char.replace('i like tutorial', 'oo', 'cc'))

The output is:

i like runccb

numpy.char.encode()

The numpy.char.encode() function calls str.encode on each element in the array. The default encoding is utf-8, and standard Python library codecs can be used.

Example

import numpy as np

a = np.char.encode('tutorial', 'cp500')
print(a)

The output is:

b'x99xa4x95x96x96x82'

numpy.char.decode()

The numpy.char.decode() function decodes encoded elements using str.decode().

Example

import numpy as np

a = np.char.encode('tutorial', 'cp500')
print(a)
print(np.char.decode(a, 'cp500'))

The output is:

b'x99xa4x95x96x96x82'
tutorial