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# matplotlib.axes.Axes.fill_between

`Axes.``fill_between`(x, y1, y2=0, where=None, interpolate=False, step=None, *, data=None, **kwargs)

  Make filled polygons between two curves.

  Create a `PolyCollection` filling the regions between y1 and y2 where `where==True`

  Parameters: | x : array An N-length array of the x data y1 : array An N-length array (or scalar) of the y data y2 : array An N-length array (or scalar) of the y data where : array, optional If `None`, default to fill between everywhere. If not `None`, it is an N-length numpy boolean array and the fill will only happen over the regions where `where==True`. interpolate : bool, optional If `True`, interpolate between the two lines to find the precise point of intersection. Otherwise, the start and end points of the filled region will only occur on explicit values in the x array. step : {‘pre’, ‘post’, ‘mid’}, optional If not None, fill with step logic.

  See also

  ``
    In addition to the above described arguments, this function can take a data keyword argument. If such a data argument is given, the following arguments are replaced by data[<arg>]: * All arguments with the following names: ‘where’, ‘x’, ‘y1’, ‘y2’.

  Notes

  Additional Keyword args passed on to the `PolyCollection`.

  kwargs control the `Polygon` properties:

  > Property | Description
  > --- | ---
  > `agg_filter` | unknown
  > `alpha` | float or None
  > `animated` | [True | False]
  > `antialiased` or antialiaseds | Boolean or sequence of booleans
  > `array` | unknown
  > `axes` | an `Axes` instance
  > `clim` | a length 2 sequence of floats
  > `clip_box` | a `matplotlib.transforms.Bbox` instance
  > `clip_on` | [True | False]
  > `clip_path` | [ (`Path`, `Transform`) | `Patch` | None ]
  > `cmap` | a colormap or registered colormap name
  > `color` | matplotlib color arg or sequence of rgba tuples
  > `contains` | a callable function
  > `edgecolor` or edgecolors | matplotlib color spec or sequence of specs
  > `facecolor` or facecolors | matplotlib color spec or sequence of specs
  > `figure` | a `matplotlib.figure.Figure` instance
  > `gid` | an id string
  > `hatch` | [ ‘/’ | ‘' | ‘|’ | ‘-‘ | ‘+’ | ‘x’ | ‘o’ | ‘O’ | ‘.’ | ‘*’ ]
  > `label` | string or anything printable with ‘%s’ conversion.
  > `linestyle` or dashes or linestyles | [‘solid’ | ‘dashed’, ‘dashdot’, ‘dotted’ | (offset, on-off-dash-seq) | `'-'` | `'--'` | `'-.'` | `':'` | `'None'` | `' '` | `''`]
  > `linewidth` or linewidths or lw | float or sequence of floats
  > `norm` | unknown
  > `offset_position` | unknown
  > `offsets` | float or sequence of floats
  > `path_effects` | unknown
  > `picker` | [None|float|boolean|callable]
  > `pickradius` | unknown
  > `rasterized` | [True | False | None]
  > `sketch_params` | unknown
  > `snap` | unknown
  > `transform` | `Transform` instance
  > `url` | a url string
  > `urls` | unknown
  > `visible` | [True | False]
  > `zorder` | any number