matplotlib.pyplot.axhline

matplotlib.pyplot.axhline(y=0, xmin=0, xmax=1, **kwargs) [source]

Add a horizontal line across the axis.

Parameters:

y : scalar, optional, default: 0: y position in data coordinates of the horizontal line.
xmin : scalar, optional, default: 0: Should be between 0 and 1, 0 being the far left of the plot, 1 the far right of the plot.
xmax : scalar, optional, default: 1: Should be between 0 and 1, 0 being the far left of the plot, 1 the far right of the plot.

Returns:

Other Parameters:

**kwargs :

Valid kwargs are Line2D properties, with the exception of '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
`alpha`	float
`animated`	bool
`antialiased`	bool
`clip_box`	`Bbox`
`clip_on`	bool
`clip_path`	[(`Path`, `Transform`) \| `Patch` \| None]
`color`	color
`contains`	callable
`dash_capstyle`	{'butt', 'round', 'projecting'}
`dash_joinstyle`	{'miter', 'round', 'bevel'}
`dashes`	sequence of floats (on/off ink in points) or (None, None)
`drawstyle`	{'default', 'steps', 'steps-pre', 'steps-mid', 'steps-post'}
`figure`	`Figure`
`fillstyle`	{'full', 'left', 'right', 'bottom', 'top', 'none'}
`gid`	str
`in_layout`	bool
`label`	object
`linestyle`	{'-', '--', '-.', ':', '', (offset, on-off-seq), ...}
`linewidth`	float
`marker`	unknown
`markeredgecolor`	color
`markeredgewidth`	float
`markerfacecolor`	color
`markerfacecoloralt`	color
`markersize`	float
`markevery`	unknown
`path_effects`	`AbstractPathEffect`
`picker`	float or callable[[Artist, Event], Tuple[bool, dict]]
`pickradius`	float
`rasterized`	bool or None
`sketch_params`	(scale: float, length: float, randomness: float)
`snap`	bool or None
`solid_capstyle`	{'butt', 'round', 'projecting'}
`solid_joinstyle`	{'miter', 'round', 'bevel'}
`transform`	matplotlib.transforms.Transform
`url`	str
`visible`	bool
`xdata`	1D array
`ydata`	1D array
`zorder`	float

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)
```