matplotlib.pyplot.fill_betweenx   matplotlib.pyplot.fill_betweenx(y, x1, x2=0, where=None, step=None, interpolate=False, *, data=None, **kwargs)[source]
 
Fill the area between two vertical curves. The curves are defined by the points (y, x1) and (y, x2). This creates one or multiple polygons describing the filled area. You may exclude some vertical sections from filling using where. By default, the edges connect the given points directly. Use step if the filling should be a step function, i.e. constant in between y.  Parameters 
 
yarray (length N)


The y coordinates of the nodes defining the curves.  
x1array (length N) or scalar


The x coordinates of the nodes defining the first curve.  
x2array (length N) or scalar, default: 0


The x coordinates of the nodes defining the second curve.  
wherearray of bool (length N), optional


Define where to exclude some vertical regions from being filled. The filled regions are defined by the coordinates y[where]. More precisely, fill between y[i] and y[i+1] if where[i] and where[i+1]. Note that this definition implies that an isolated True value between two False values in where will not result in filling. Both sides of the True position remain unfilled due to the adjacent False values.  
interpolatebool, default: False


This option is only relevant if where is used and the two curves are crossing each other. Semantically, where is often used for x1 > x2 or similar. By default, the nodes of the polygon defining the filled region will only be placed at the positions in the y array. Such a polygon cannot describe the above semantics close to the intersection. The y-sections containing the intersection are simply clipped. Setting interpolate to True will calculate the actual intersection point and extend the filled region up to this point.  
step{'pre', 'post', 'mid'}, optional


Define step if the filling should be a step function, i.e. constant in between y. The value determines where the step will occur:  'pre': The y value is continued constantly to the left from every x position, i.e. the interval (x[i-1], x[i]] has the value y[i]. 'post': The y value is continued constantly to the right from every x position, i.e. the interval [x[i], x[i+1]) has the value y[i]. 'mid': Steps occur half-way between the x positions.     Returns 
 PolyCollection

A PolyCollection containing the plotted polygons.    Other Parameters 
 
dataindexable object, optional


If given, the following parameters also accept a string s, which is interpreted as data[s] (unless this raises an exception): y, x1, x2, where  **kwargs

All other keyword arguments are passed on to PolyCollection. They control the Polygon 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  
alpha array-like or scalar or None  
animated bool  
antialiased or aa or antialiaseds bool or list of bools  
array array-like or None  
capstyle CapStyle or {'butt', 'projecting', 'round'}  
clim (vmin: float, vmax: float)  
clip_box Bbox  
clip_on bool  
clip_path Patch or (Path, Transform) or None  
cmap Colormap or str or None  
color color or list of rgba tuples  
edgecolor or ec or edgecolors color or list of colors or 'face'  
facecolor or facecolors or fc color or list of colors  
figure Figure  
gid str  
hatch {'/', '\', '|', '-', '+', 'x', 'o', 'O', '.', '*'}  
in_layout bool  
joinstyle JoinStyle or {'miter', 'round', 'bevel'}  
label object  
linestyle or dashes or linestyles or ls str or tuple or list thereof  
linewidth or linewidths or lw float or list of floats  
norm Normalize or None  
offset_transform Transform  
offsets (N, 2) or (2,) array-like  
path_effects AbstractPathEffect  
paths list of array-like  
picker None or bool or float or callable  
pickradius float  
rasterized bool  
sizes 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.