matplotlib.pyplot.axhline

matplotlib.pyplot.axhline(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 hlines instead.

Parameters:

yfloat, default: 0

y position in data coordinates.

xminfloat, default: 0

The start x-position in axes coordinates. Should be between 0 and 1, 0 being the far left of the plot, 1 the far right of the plot.

xmaxfloat, default: 1

The end x-position in axes coordinates. Should be between 0 and 1, 0 being the far left of the plot, 1 the far right of the plot.

Returns:

Line2D

A Line2D specified via two points (xmin, y), (xmax, y). Its transform is set such that x is in axes coordinates and y is in data coordinates.

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':

Property	Description
agg_filter	a filter function, which takes a (m, n, 3) float array and a dpi value, and returns a (m, n, 3) array and two offsets from the bottom left corner of the image
alpha	scalar or None
animated	bool
antialiased or aa	bool
clip_box	BboxBase or None
clip_on	bool
clip_path	Patch or (Path, Transform) or None
color or c	color
dash_capstyle	CapStyle or {'butt', 'projecting', 'round'}
dash_joinstyle	JoinStyle or {'miter', 'round', 'bevel'}
dashes	sequence of floats (on/off ink in points) or (None, None)
data	(2, N) array or two 1D arrays
drawstyle or ds	{'default', 'steps', 'steps-pre', 'steps-mid', 'steps-post'}, default: 'default'
figure	Figure or SubFigure
fillstyle	{'full', 'left', 'right', 'bottom', 'top', 'none'}
gapcolor	color or None
gid	str
in_layout	bool
label	object
linestyle or ls	{'-', '--', '-.', ':', '', (offset, on-off-seq), ...}
linewidth or lw	float
marker	marker style string, Path or MarkerStyle
markeredgecolor or mec	color
markeredgewidth or mew	float
markerfacecolor or mfc	color
markerfacecoloralt or mfcalt	color
markersize or ms	float
markevery	None or int or (int, int) or slice or list[int] or float or (float, float) or list[bool]
mouseover	bool
path_effects	list of AbstractPathEffect
picker	float or callable[[Artist, Event], tuple[bool, dict]]
pickradius	float
rasterized	bool
sketch_params	(scale: float, length: float, randomness: float)
snap	bool or None
solid_capstyle	CapStyle or {'butt', 'projecting', 'round'}
solid_joinstyle	JoinStyle or {'miter', 'round', 'bevel'}
transform	unknown
url	str
visible	bool
xdata	1D array
ydata	1D array
zorder	float

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.

Notes

Note

This is the pyplot wrapper for axes.Axes.axhline.

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)
  

• draw a default hline at 'y' = .5 that spans the middle half of the xrange:

  >>> axhline(y=.5, xmin=0.25, xmax=0.75)
  

Examples using matplotlib.pyplot.axhline

Infinite lines

Infinite lines

Zorder Demo

Zorder Demo