NumPy String: numpy.char.count() function

Last update on March 29 2023 09:21:34 (UTC/GMT +8 hours)

numpy.char.count() function

The numpy.char.count() function returns an array with the number of non-overlapping occurrences of substring sub in the range [start, end].

The numpy.char.count() function is useful in text processing and data cleaning tasks, where one needs to count the frequency of a particular word or character in a given dataset. This function can be used to extract information from a dataset by counting the occurrences of a particular keyword.

Syntax:

numpy.char.count(a, sub, start=0, end=None)

Parameters:

Name	Description	Required / Optional
a: array_like of str or unicode	Input an array_like of string or unicode.	Required
sub: str or unicode	The substring to search for.	Required
start, end: int	Optional arguments start and end are interpreted as slice notation to specify the range in which to count.	Optional

Return value:

out : ndarray - Output array of ints.

Example: Counting occurrences of a substring in a numpy string array


>>> c = np.array(['aAaAaA', '  aA  ', 'abBABba'])
>>> c
array(['aAaAaA', '  aA  ', 'abBABba'],
    dtype='|S7')
>>> np.char.count(c, 'A')
array([3, 1, 1])
>>> np.char.count(c, 'aA')
array([3, 1, 0])
>>> np.char.count(c, 'A', start=1, end=4)
array([2, 1, 1])
>>> np.char.count(c, 'A', start=1, end=3)
array([1, 0, 0])

The above code demonstrates the application of the numpy.char.count() function to count the number of occurrences of a substring within a numpy string array. The function is also used to count the number of occurrences of a substring within a specific range of indices in each element of the array.

Pictorial Presentation:

NumPy String operation: numpy.char.count() function

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