Function slice

numpy/_core/strings.py:1730–1813

Slice the strings in `a` by slices specified by `start`, `stop`, `step`. Like in the regular Python `slice` object, if only `start` is specified then it is interpreted as the `stop`. Parameters ---------- a : array-like, with ``StringDType``, ``bytes_``, or ``str_`` dtype

(a, start=None, stop=np._NoValue, step=None, /)

@set_module("numpy.strings")
def slice(a, start=None, stop=np._NoValue, step=None, /):
    """
    Slice the strings in `a` by slices specified by `start`, `stop`, `step`.
    Like in the regular Python `slice` object, if only `start` is
    specified then it is interpreted as the `stop`.

    Parameters
    ----------
    a : array-like, with ``StringDType``, ``bytes_``, or ``str_`` dtype
        Input array

    start : None, an integer or an array of integers
        The start of the slice, broadcasted to `a`'s shape

    stop : None, an integer or an array of integers
        The end of the slice, broadcasted to `a`'s shape

    step : None, an integer or an array of integers
        The step for the slice, broadcasted to `a`'s shape

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

    Examples
    --------
    >>> import numpy as np
    >>> a = np.array(['hello', 'world'])
    >>> np.strings.slice(a, 2)
    array(['he', 'wo'], dtype='<U5')

    >>> np.strings.slice(a, 2, None)
    array(['llo', 'rld'], dtype='<U5')

    >>> np.strings.slice(a, 1, 5, 2)
    array(['el', 'ol'], dtype='<U5')

    One can specify different start/stop/step for different array entries:

    >>> np.strings.slice(a, np.array([1, 2]), np.array([4, 5]))
    array(['ell', 'rld'], dtype='<U5')

    Negative slices have the same meaning as in regular Python:

    >>> b = np.array(['hello world', 'γεια σου κόσμε', '你好世界', '👋 🌍'],
    ...              dtype=np.dtypes.StringDType())
    >>> np.strings.slice(b, -2)
    array(['hello wor', 'γεια σου κόσ', '你好', '👋'], dtype=StringDType())

    >>> np.strings.slice(b, -2, None)
    array(['ld', 'με', '世界', ' 🌍'], dtype=StringDType())

    >>> np.strings.slice(b, [3, -10, 2, -3], [-1, -2, -1, 3])
    array(['lo worl', ' σου κόσ', '世', '👋 🌍'], dtype=StringDType())

    >>> np.strings.slice(b, None, None, -1)