Function lstrip

numpy/_core/strings.py:943–987

For each element in `a`, return a copy with the leading characters removed. Parameters ---------- a : array-like, with ``StringDType``, ``bytes_``, or ``str_`` dtype chars : scalar with the same dtype as ``a``, optional The ``chars`` argument is a string specifying t

(a, chars=None)

@set_module("numpy.strings")
def lstrip(a, chars=None):
    """
    For each element in `a`, return a copy with the leading characters
    removed.

    Parameters
    ----------
    a : array-like, with ``StringDType``, ``bytes_``, or ``str_`` dtype
    chars : scalar with the same dtype as ``a``, optional
       The ``chars`` argument is a string specifying the set of
       characters to be removed. If ``None``, the ``chars``
       argument defaults to removing whitespace. The ``chars`` argument
       is not a prefix or suffix; rather, all combinations of its
       values are stripped.

    Returns
    -------
    out : ndarray
        Output array of ``StringDType``, ``bytes_`` or ``str_`` dtype,
        depending on input types

    See Also
    --------
    str.lstrip

    Examples
    --------
    >>> import numpy as np
    >>> c = np.array(['aAaAaA', '  aA  ', 'abBABba'])
    >>> c
    array(['aAaAaA', '  aA  ', 'abBABba'], dtype='<U7')
    # The 'a' variable is unstripped from c[1] because of leading whitespace.
    >>> np.strings.lstrip(c, 'a')
    array(['AaAaA', '  aA  ', 'bBABba'], dtype='<U7')
    >>> np.strings.lstrip(c, 'A') # leaves c unchanged
    array(['aAaAaA', '  aA  ', 'abBABba'], dtype='<U7')
    >>> (np.strings.lstrip(c, ' ') == np.strings.lstrip(c, '')).all()
    np.False_
    >>> (np.strings.lstrip(c, ' ') == np.strings.lstrip(c)).all()
    np.True_

    """
    if chars is None:
        return _lstrip_whitespace(a)
    return _lstrip_chars(a, chars)


@set_module("numpy.strings")