Numpy | String Operations
This module is used to perform vectorized string operations for arrays of dtype numpy.string_ or numpy.unicode_. All of them are based on the standard string functions in Python’s built-in library.
String Operations –
numpy.lower() : This function returns the lowercase string from the given string. It converts all uppercase characters to lowercase. If no uppercase characters exist, it returns the original string.
# Python program explaining
# numpy.lower() function
import numpy as np
# converting to lowercase
print(np.char.lower(['GEEKS', 'FOR']))
# converting to lowercase
print(np.char.lower('GEEKS'))
Output :
['geeks' 'for'] geeks
numpy.split() : This function returns a list of strings after breaking the given string by the specified separator.
# Python program explaining
# numpy.split() function
import numpy as np
# splitting a string
print(np.char.split('geeks for geeks'))
# splitting a string
print(np.char.split('geeks, for, geeks', sep = ','))
Output :
['geeks', 'for', 'geeks'] ['geeks', 'for', 'geeks']
numpy.join() : This function is a string method and returns a string in which the elements of sequence have been joined by str separator.
# Python program explaining
# numpy.join() function
import numpy as np
# splitting a string
print(np.char.join('-', 'geeks'))
# splitting a string
print(np.char.join(['-', ':'], ['geeks', 'for']))
Output :
g-e-e-k-s ['g-e-e-k-s', 'g:e:e:k:s']
| Function | Description |
|---|---|
| numpy.strip() | It is used to remove all the leading and trailing spaces from a string. |
| numpy.capitalize() | It converts the first character of a string to capital (uppercase) letter. If the string has its first character as capital, then it returns the original string. |
| numpy.center() | It creates and returns a new string which is padded with the specified character.. |
| numpy.decode() | It is used to convert from one encoding scheme, in which argument string is encoded to the desired encoding scheme. |
| numpy.encode() | Returns the string in the encoded form |
| numpy.ljust() | Return an array with the elements of a left-justified in a string of length width. |
| numpy.rjust() | For each element in a, return a copy with the leading characters removed. |
| numpy.strip() | For each element in a, return a copy with the leading and trailing characters removed. |
| numpy.lstrip() | Convert angles from degrees to radians. |
| numpy.rstrip() | For each element in a, return a copy with the trailing characters removed. |
| numpy.partition() | Partition each element in a around sep. |
| numpy.rpartition | Partition (split) each element around the right-most separator. |
| numpy.rsplit() | For each element in a, return a list of the words in the string, using sep as the delimiter string. |
| numpy.title() | It is used to convert the first character in each word to Uppercase and remaining characters to Lowercase in string and returns new string. |
| numpy.upper() | Returns the uppercased string from the given string. It converts all lowercase characters to uppercase.If no lowercase characters exist, it returns the original string. |
String Information –
numpy.count() : This function returns the number of occurrences of a substring in the given string.
# Python program explaining # numpy.count() function import numpy as np a=np.array(['geeks', 'for', 'geeks']) # counting a substring print(np.char.count(a,'geek')) # counting a substring print(np.char.count(a, 'fo'))
Output :
[1, 0, 1] [0, 1, 0]
numpy.rfind() : This function returns the highest index of the substring if found in given string. If not found then it returns -1.
# Python program explaining # numpy.rfind() function import numpy as np a=np.array(['geeks', 'for', 'geeks']) # counting a substring print(np.char.rfind(a,'geek')) # counting a substring print(np.char.rfind(a, 'fo'))
Output :
[0, -1, 0] [-1, 0, -1]
numpy.isnumeric() : This function returns “True” if all characters in the string are numeric characters, Otherwise, It returns “False”.
# Python program explaining
# numpy.isnumeric() function
import numpy as np
# counting a substring
print(np.char.isnumeric('geeks'))
# counting a substring
print(np.char.isnumeric('12geeks'))
Output :
False False
| Function | Description |
|---|---|
| numpy.find() | It returns the lowest index of the substring if it is found in given string. If its is not found then it returns -1. |
| numpy.index() | It returns the position of the first occurrence of substring in a string |
| numpy.isalpha() | It returns “True” if all characters in the string are alphabets, Otherwise, It returns “False”. |
| numpy.isdecimal() | It returns true if all characters in a string are decimal. If all characters are not decimal then it returns false. |
| numpy.isdigit() | It returns “True” if all characters in the string are digits, Otherwise, It returns “False”. |
| numpy.islower() | It returns “True” if all characters in the string are lowercase, Otherwise, It returns “False”. |
| numpy.isspace() | Returns true for each element if there are only whitespace characters in the string and there is at least one character, false otherwise. |
| numpy.istitle() | Returns true for each element if the element is a titlecased string and there is at least one character, false otherwise. |
| numpy.isupper() | Returns true for each element if all cased characters in the string are uppercase and there is at least one character, false otherwise. |
| numpy.rindex() | Returns the highest index of the substring inside the string if substring is found. Otherwise it raises an exception. |
| numpy.startswith() | Returns True if a string starts with the given prefix otherwise returns False. |
String Comparison –
numpy.equal(): This function checks for string1 == string2 elementwise.
# Python program explaining
# numpy.equal() function
import numpy as np
# comparing a string elementwise
# using equal() method
a=np.char.equal('geeks','for')
print(a)
Output :
False
numpy.not_equal(): This function checks whether two string is unequal or not.
# Python program explaining
# numpy.unequal() function
import numpy as np
# comparing a string elementwise
# using unequal() method
a=np.char.unequal('geeks','for')
print(a)
Output :
True
numpy.greater(): This function checks whether string1 is greater than string2 or not.
# Python program explaining
# numpy.greater() function
import numpy as np
# comparing a string elementwise
# using greater() method
a=np.char.greater('geeks','for')
print(a)
Output :
True
| Function | Description |
|---|---|
| numpy.greater_equal() | It checks whether string1 >= string2 or not. |
| numpy.less_equal() | It checks whether string1 is <= string2 or not. |
| numpy.less() | It check whether string1 is lesser than string2 or not. |
