numpy.core.defchararray.lstrip()

numpy.core.defchararray.lstrip(a, chars=None) [source]

For each element in a, return a copy with the leading characters removed.

Calls str.lstrip element-wise.

Parameters:

Parameters:	a : array-like, {str, unicode} Input array. chars : {str, unicode}, optional The `chars` argument is a string specifying the set of characters to be removed. If omitted or None, the `chars` argument defaults to removing whitespace. The `chars` argument is not a prefix; rather, all combinations of its values are stripped.
Returns:	out : ndarray, {str, unicode} Output array of str or unicode, depending on input type

a : array-like, {str, unicode}

Input array.

chars : {str, unicode}, optional

The chars argument is a string specifying the set of characters to be removed. If omitted or None, the chars argument defaults to removing whitespace. The chars argument is not a prefix; rather, all combinations of its values are stripped.

Returns:

out : ndarray, {str, unicode}

Output array of str or unicode, depending on input type

Examples

>>> c = np.array(['aAaAaA', '  aA  ', 'abBABba'])
>>> c
array(['aAaAaA', '  aA  ', 'abBABba'],
    dtype='|S7')

The ?a? variable is unstripped from c[1] because whitespace leading.

>>> np.char.lstrip(c, 'a')
array(['AaAaA', '  aA  ', 'bBABba'],
    dtype='|S7')

>>> np.char.lstrip(c, 'A') # leaves c unchanged
array(['aAaAaA', '  aA  ', 'abBABba'],
    dtype='|S7')
>>> (np.char.lstrip(c, ' ') == np.char.lstrip(c, '')).all()
... # XXX: is this a regression? this line now returns False
... # np.char.lstrip(c,'') does not modify c at all.
True
>>> (np.char.lstrip(c, ' ') == np.char.lstrip(c, None)).all()
True

Links:

https://docs.scipy.org/doc/numpy-1.11.0/reference/generated/numpy.core.defchararray.lstrip.html

doc_NumPy

2017-01-10 18:13:22

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