NumPy – String Functions:

In Numpy, we can handle the string operations with provided functions. some of which we can discuss here.

add: This will return element-wise string concatenation for two arrays of str.

Example:

>>> x=np.array(("iam a numpy"))

>>> y=np.array(("program"))

>>> np.char.add(x,y)
array('iam a numpyprogram',dtype='<U18')

multiply: This will return element-wise string multiple concatenation.

Example:

>>> import numpy as np

>>> x=np.char.multiply("numpy",5)

>>> x
array('numpynumpynumpynumpynumpy', dtype='<U25')

>>> print(x)
numpynumpynumpynumpynumpy

capitalize: This will return a copy of string with first character of each element capitalized.

Example:

>>> import numpy as np

>>> x=np.char.capitalize("numpy")

>>> x
array('Numpy', dtype='<U5')

>>> print(x)
Numpy

split: This will return a list of words in the string.

Example:

>>> import numpy as np

>>> x=np.char.split("iam a numpy program")

>>> print(x)
['iam', 'a', 'numpy', 'program']

lower: This will return an array with elements converted to lowercase.

Example:

>>> import numpy as np

>>> x=np.char.lower("NUMPY")

>>> print(x)
numpy

upper: This will return an array with elements converted to uppercase.

Example:

>>> import numpy as np

>>> x=np.char.upper("numpy")

>>> print(x)
NUMPY

equal: This will return a element-wise comparision.

Example:

>>> x=np.char.equal("iam","numpy")

>>> print(x)
False

not_equal: This will return a element-wise comparision.

Example:

>>> x=np.char.not_equal("iam","numpy")

>>> print(x)
True

count: This will return an array with the number of non-overlapping occurances of substring in the range.

Example:

>>> x=np.array(['bet','abet','alphabet'])

>>> x
array(['bet', 'abet', 'alphabet'],dtype='<U8')

>>> np.char.count(x,'bet')
array([1, 1, 1])

>>> np.char.count(x,'abet')
array([0, 1, 1])

>>> np.char.count(x,'alphabet')
array([0, 0, 1])

isnumeric: This will return true if there is only numeric characters in the element.

Example:

>>> np.char.isnumeric('bet')
array(False, dtype=bool)

rfind: This will return the highest index in the string where substring is found.

Example:

>>> x=np.array(['bet','abet','alphabet'])

>>> x
array(['bet', 'abet', 'alphabet'],dtype='<U8')

>>> np.char.rfind(x,'abet')
array([-1, 0, 4])
>>> np.char.rfind(x,'bet')
array([0, 1, 5])
>>> np.char.rfind(x,'alphabet')
array([-1, -1, 0])