matplotlib.pyplot.fill_between#

matplotlib.pyplot.fill_between(x,y1,y2=0,where=None,interpolate=False,step=None,*,data=None,**kwargs)[source]#

Fill the area between two horizontal curves.

The curves are defined by the points (x,y1) and (x,y2). This creates one or multiple polygons describing the filledarea.

You may exclude some horizontal sections from filling usingwhere.

By default, the edges connect the given points directly. Usestepif the filling should be a step function, i.e. constant in betweenx.

Parameters:

xarray-like

The x coordinates of the nodes defining the curves.

y1array-like or float

The y coordinates of the nodes defining the first curve.

y2array-like or float, default: 0

The y coordinates of the nodes defining the second curve.

wherearray-like of bool, optional

Definewhere to exclude some horizontal regions from being filled.The filled regions are defined by the coordinatesx[where].More precisely, fill betweenx[i] andx[i+1] ifwhere[i]andwhere[i+1]. Note that this definition impliesthat an isolatedTrue value between twoFalse values inwherewill not result in filling. Both sides of theTrue positionremain unfilled due to the adjacentFalse values.

interpolatebool, default: False

This option is only relevant ifwhere is used and the two curvesare crossing each other.

Semantically,where is often used fory1 >y2 orsimilar. By default, the nodes of the polygon defining the filledregion will only be placed at the positions in thex array.Such a polygon cannot describe the above semantics close to theintersection. The x-sections containing the intersection aresimply clipped.

Settinginterpolate toTrue will calculate the actualintersection point and extend the filled region up to this point.

step{'pre', 'post', 'mid'}, optional

Definestep if the filling should be a step function,i.e. constant in betweenx. The value determines where thestep will occur:

• 'pre': The y value is continued constantly to the left fromeveryx position, i.e. the interval(x[i-1],x[i]]has the valuey[i].

• 'post': The y value is continued constantly to the right fromeveryx position, i.e. the interval[x[i],x[i+1])has the valuey[i].

• 'mid': Steps occur half-way between thex positions.

Returns:

FillBetweenPolyCollection

AFillBetweenPolyCollection containing the plotted polygons.

Other Parameters:

dataindexable object, optional

If given, the following parameters also accept a strings, which isinterpreted asdata[s] ifs is a key indata:

x,y1,y2,where

**kwargs

All other keyword arguments are passed on toFillBetweenPolyCollection. They control thePolygon properties:

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	array-like or float or None
animated	bool
antialiased oraa orantialiaseds	bool or list of bools
array	array-like or None
capstyle	CapStyle or {'butt', 'projecting', 'round'}
clim	(vmin: float, vmax: float)
clip_box	BboxBase or None
clip_on	bool
clip_path	Patch or (Path, Transform) or None
cmap	Colormap or str or None
color	color or list of RGBA tuples
data	array-like
edgecolor orec oredgecolors	color or list ofcolor or 'face'
facecolor orfacecolors orfc	color or list ofcolor
figure	Figure orSubFigure
gid	str
hatch	{'/', '\', '|', '-', '+', 'x', 'o', 'O', '.', '*'}
hatch_linewidth	unknown
hatchcolor	color or list ofcolor or 'edge'
in_layout	bool
joinstyle	JoinStyle or {'miter', 'round', 'bevel'}
label	object
linestyle ordashes orlinestyles orls	str or tuple or list thereof
linewidth orlinewidths orlw	float or list of floats
mouseover	bool
norm	Normalize or str or None
offset_transform ortransOffset	Transform
offsets	(N, 2) or (2,) array-like
path_effects	list ofAbstractPathEffect
paths	list of array-like
picker	None or bool or float or callable
pickradius	float
rasterized	bool
sizes	numpy.ndarray or None
sketch_params	(scale: float, length: float, randomness: float)
snap	bool or None
transform	Transform
url	str
urls	list of str or None
verts	list of array-like
verts_and_codes	unknown
visible	bool
zorder	float

See also

fill_between

Fill between two sets of y-values.

fill_betweenx

Fill between two sets of x-values.

Notes

Note

This is thepyplot wrapper foraxes.Axes.fill_between.

Examples usingmatplotlib.pyplot.fill_between#

Fill the area between two lines

Fill the area between two lines