Method axhline

lib/matplotlib/axes/_axes.py:748–828

Add a horizontal line spanning the whole or fraction of the Axes. Note: If you want to set x-limits in data coordinates, use `~.Axes.hlines` instead. Parameters ---------- y : float, default: 0 y position in :ref:`data coordinates <coord

(self, y=0, xmin=0, xmax=1, **kwargs)

    @_docstring.interpd
    def axhline(self, y=0, xmin=0, xmax=1, **kwargs):
        """
        Add a horizontal line spanning the whole or fraction of the Axes.

        Note: If you want to set x-limits in data coordinates, use
        `~.Axes.hlines` instead.

        Parameters
        ----------
        y : float, default: 0
            y position in :ref:`data coordinates <coordinate-systems>`.

        xmin : float, default: 0
            The start x-position in :ref:`axes coordinates <coordinate-systems>`.
            Should be between 0 and 1, 0 being the far left of the plot,
            1 the far right of the plot.

        xmax : float, default: 1
            The end x-position in :ref:`axes coordinates <coordinate-systems>`.
            Should be between 0 and 1, 0 being the far left of the plot,
            1 the far right of the plot.

        Returns
        -------
        `~matplotlib.lines.Line2D`
            A `.Line2D` specified via two points ``(xmin, y)``, ``(xmax, y)``.
            Its transform is set such that *x* is in
            :ref:`axes coordinates <coordinate-systems>` and *y* is in
            :ref:`data coordinates <coordinate-systems>`.

            This is still a generic line and the horizontal character is only
            realized through using identical *y* values for both points. Thus,
            if you want to change the *y* value later, you have to provide two
            values ``line.set_ydata([3, 3])``.

        Other Parameters
        ----------------
        **kwargs
            Valid keyword arguments are `.Line2D` properties, except for
            'transform':

            %(Line2D:kwdoc)s

        See Also
        --------
        hlines : Add horizontal lines in data coordinates.
        axhspan : Add a horizontal span (rectangle) across the axis.
        axline : Add a line with an arbitrary slope.

        Examples
        --------
        * draw a thick red hline at 'y' = 0 that spans the xrange::

            >>> axhline(linewidth=4, color='r')

        * draw a default hline at 'y' = 1 that spans the xrange::

            >>> axhline(y=1)