python——linspace函数

def linspace(start, stop, num=50, endpoint=True, retstep=False, dtype=None,
             axis=0):
"""
    Return evenly spaced numbers over a specified interval.

    Returns num evenly spaced samples, calculated over the
    interval [start, stop].

    The endpoint of the interval can optionally be excluded.

    .. versionchanged:: 1.16.0
        Non-scalar start and stop are now supported.

    .. versionchanged:: 1.20.0
        Values are rounded towards -inf instead of 0 when an
        integer  is specified. The old behavior can
        still be obtained with .linspace(start, stop, num).astype(int)

    Parameters
    ----------
    start : array_like
        The starting value of the sequence.

    stop : array_like
        The end value of the sequence, unless endpoint is set to False.

        In that case, the sequence consists of all but the last of  + 1
        evenly spaced samples, so that stop is excluded.  Note that the step
        size changes when endpoint is False.

    num : int, optional
        Number of samples to generate. Default is 50. Must be non-negative.

    endpoint : bool, optional
        If True, stop is the last sample. Otherwise, it is not included.

        Default is True.

    retstep : bool, optional
        If True, return (samples, step), where step is the spacing
        between samples.

    dtype : dtype, optional
        The type of the output array.  If dtype is not given, the data type
        is inferred from start and stop. The inferred dtype will never be
        an integer; float is chosen even if the arguments would produce an
        array of integers.

        .. versionadded:: 1.9.0

    axis : int, optional
        The axis in the result to store the samples.  Relevant only if start
        or stop are array-like.  By default (0), the samples will be along a
        new axis inserted at the beginning. Use -1 to get an axis at the end.

        .. versionadded:: 1.16.0

    Returns
    -------
    samples : ndarray
        There are num equally spaced samples in the closed interval
        [start, stop] or the half-open interval [start, stop)
        (depending on whether endpoint is True or False).

    step : float, optional
        Only returned if retstep is True

        Size of spacing between samples.

    See Also
    --------
    arange : Similar to linspace, but uses a step size (instead of the
             number of samples).

    geomspace : Similar to linspace, but with numbers spaced evenly on a log
                scale (a geometric progression).

    logspace : Similar to geomspace, but with the end points specified as
               logarithms.

    Examples
    --------
    >>> np.linspace(2.0, 3.0, num=5)
    array([2.  , 2.25, 2.5 , 2.75, 3.  ])
    >>> np.linspace(2.0, 3.0, num=5, endpoint=False)
    array([2. ,  2.2,  2.4,  2.6,  2.8])
    >>> np.linspace(2.0, 3.0, num=5, retstep=True)
    (array([2.  ,  2.25,  2.5 ,  2.75,  3.  ]), 0.25)

    Graphical illustration:

    >>> import matplotlib.pyplot as plt
    >>> N = 8
    >>> y = np.zeros(N)
    >>> x1 = np.linspace(0, 10, N, endpoint=True)
    >>> x2 = np.linspace(0, 10, N, endpoint=False)
    >>> plt.plot(x1, y, 'o')
    []
    >>> plt.plot(x2, y + 0.5, 'o')
    []
    >>> plt.ylim([-0.5, 1])
    (-0.5, 1)
    >>> plt.show()

"""
    num = operator.index(num)
    if num < 0:
        raise ValueError("Number of samples, %s, must be non-negative." % num)
    div = (num - 1) if endpoint else num

    # Convert float/complex array scalars to float, gh-3504
    # and make sure one can use variables that have an __array_interface__, gh-6634
    start = asanyarray(start) * 1.0
    stop  = asanyarray(stop)  * 1.0

    dt = result_type(start, stop, float(num))
    if dtype is None:
        dtype = dt

    delta = stop - start
    y = _nx.arange(0, num, dtype=dt).reshape((-1,) + (1,) * ndim(delta))
    # In-place multiplication y *= delta/div is faster, but prevents the multiplicant
    # from overriding what class is produced, and thus prevents, e.g. use of Quantities,
    # see gh-7142. Hence, we multiply in place only for standard scalar types.

    _mult_inplace = _nx.isscalar(delta)
    if div > 0:
        step = delta / div
        if _nx.any(step == 0):
            # Special handling for denormal numbers, gh-5437
            y /= div
            if _mult_inplace:
                y *= delta
            else:
                y = y * delta
        else:
            if _mult_inplace:
                y *= step
            else:
                y = y * step
    else:
        # sequences with 0 items or 1 item with endpoint=True (i.e. div  1:
        y[-1] = stop

    if axis != 0:
        y = _nx.moveaxis(y, 0, axis)

    if _nx.issubdtype(dtype, _nx.integer):
        _nx.floor(y, out=y)

    if retstep:
        return y.astype(dtype, copy=False), step
    else:
        return y.astype(dtype, copy=False)

返回指定间隔内的等距数字。

返回”num”均匀分布的样本,在 间隔[‘start’,’stop]。返回指定间隔内的等距数字。</strong></p> <p><strong>可以选择排除间隔的端点。</strong></p> <p><strong>----------</strong></p> <p><strong>start:</strong> <strong>array_like</strong></p> <p><strong>序列的起始值。</strong></p> <p><strong>stop:</strong> <strong>array_like</strong></p> <p><strong>序列的结束值,除非"endpoint"设置为False。</strong> <strong>在这种情况下,序列由除最后一个以外的所有<code>num+1组成</code></strong> <strong>均匀分布的样本,以便排除"停止"。请注意,步骤</strong> <strong>当"endpoint"为False时,大小会发生变化。</strong></p> <p><strong>num:int,可选</strong></p> <p><strong>要生成的样本数。默认值为50。必须是非负的。</strong></p> <p><strong>端点:bool,可选</strong></p> <p><strong>如果为True,"stop"是最后一个示例。否则不包括在内。</strong> <strong>默认是真的。</strong></p> <p><strong>retstep:bool,可选</strong></p> <p><strong>如果为True,则返回('samples','step'),其中'step'是间距</strong></p> <p><strong>在样本之间。</strong></p> <p><strong>dtype:dtype,可选</strong></p> <p><strong>输出数组的类型。如果未给出'dtype',则为数据类型</strong> <strong>由"开始"和"停止"推断。推断出的数据类型永远不会被删除</strong> <strong>整数即使参数会产生 整数数组。

轴:int,可选
结果中用于存储样本的轴。只有在启动时才相关或停止是阵列式的。默认情况下(0),样本将沿着开始处插入新轴。使用-1在末尾获得一个轴。

Returns
——-

samples :Ndaray
在闭合间隔中有’num’等间距的样本
[start,stop]或半开区间或[start,stop]</code><br> (取决于"endpoint"是真是假)。</strong></p> <p><strong>step : float, optional<br> 仅当'retstep'为真时返回<br> 样本之间的间距大小。<br> 另见<br>--------<br>arange:与"linspace"类似,但使用步长(而不是样本数量)。<br>geomspace:类似于"linspace",但数字在一根圆木上均匀分布比例(几何级数)。<br>logspace:类似于"geomspace",但端点指定为对数。</strong></p> <p>
Examples

Original: https://blog.csdn.net/weixin_53660567/article/details/123160542
Author: 长沙有肥鱼
Title: python——linspace函数

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