numpy.strings.isalpha

strings.isalpha(x, /, out=None, *, where=True, casting='same_kind', order='K', dtype=None, subok=True[, signature]) = <ufunc 'isalpha'>

Returns true for each element if all characters in the data interpreted as a string are alphabetic and there is at least one character, false otherwise.

For byte strings (i.e. bytes), alphabetic characters are those byte values in the sequence b’abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ’. For Unicode strings, alphabetic characters are those characters defined in the Unicode character database as “Letter”.

Parameters:

xarray_like, with StringDType, bytes_, or str_ dtype

outndarray, None, or tuple of ndarray and None, optional

A location into which the result is stored. If provided, it must have a shape that the inputs broadcast to. If not provided or None, a freshly-allocated array is returned. A tuple (possible only as a keyword argument) must have length equal to the number of outputs.

wherearray_like, optional

This condition is broadcast over the input. At locations where the condition is True, the out array will be set to the ufunc result. Elsewhere, the out array will retain its original value. Note that if an uninitialized out array is created via the default out=None, locations within it where the condition is False will remain uninitialized.

**kwargs

For other keyword-only arguments, see the ufunc docs.

Returns:

yndarray

Output array of bools This is a scalar if x is a scalar.

See also

str.isalpha

Examples

>>> import numpy as np
>>> a = np.array(['a', 'b', '0'])
>>> np.strings.isalpha(a)
array([ True,  True, False])

>>> a = np.array([['a', 'b', '0'], ['c', '1', '2']])
>>> np.strings.isalpha(a)
array([[ True,  True, False], [ True, False, False]])