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DocumentationDocumentation: APIfiles in lib/ and doc/apifiles in lib/ and doc/apiGood first issueOpen a pull request against these issues if there are no active ones!Open a pull request against these issues if there are no active ones!
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matplotlib/lib/matplotlib/colors.py
Lines 2708 to 2762 in 3958242
| def from_levels_and_colors(levels, colors, extend='neither'): | |
| """ | |
| A helper routine to generate a cmap and a norm instance which | |
| behave similar to contourf's levels and colors arguments. | |
| Parameters | |
| ---------- | |
| levels : sequence of numbers | |
| The quantization levels used to construct the `BoundaryNorm`. | |
| Value ``v`` is quantized to level ``i`` if ``lev[i] <= v < lev[i+1]``. | |
| colors : sequence of colors | |
| The fill color to use for each level. If *extend* is "neither" there | |
| must be ``n_level - 1`` colors. For an *extend* of "min" or "max" add | |
| one extra color, and for an *extend* of "both" add two colors. | |
| extend : {'neither', 'min', 'max', 'both'}, optional | |
| The behaviour when a value falls out of range of the given levels. | |
| See `~.Axes.contourf` for details. | |
| Returns | |
| ------- | |
| cmap : `~matplotlib.colors.Normalize` | |
| norm : `~matplotlib.colors.Colormap` | |
| """ | |
| slice_map = { | |
| 'both': slice(1, -1), | |
| 'min': slice(1, None), | |
| 'max': slice(0, -1), | |
| 'neither': slice(0, None), | |
| } | |
| _api.check_in_list(slice_map, extend=extend) | |
| color_slice = slice_map[extend] | |
| n_data_colors = len(levels) - 1 | |
| n_expected = n_data_colors + color_slice.start - (color_slice.stop or 0) | |
| if len(colors) != n_expected: | |
| raise ValueError( | |
| f'With extend == {extend!r} and {len(levels)} levels, ' | |
| f'expected {n_expected} colors, but got {len(colors)}') | |
| cmap = ListedColormap(colors[color_slice], N=n_data_colors) | |
| if extend in ['min', 'both']: | |
| cmap.set_under(colors[0]) | |
| else: | |
| cmap.set_under('none') | |
| if extend in ['max', 'both']: | |
| cmap.set_over(colors[-1]) | |
| else: | |
| cmap.set_over('none') | |
| cmap.colorbar_extend = extend | |
| norm = BoundaryNorm(levels, ncolors=n_data_colors) | |
| return cmap, norm |
The docstring of matplotlib.colors.from_levels_and_colors states that the function returns:
cmap : `~matplotlib.colors.Normalize`
norm : `~matplotlib.colors.Colormap`
while the code confirms that, as expected, it's the opposite that is returned (cmap is a Colormap and norm is a Normalize)
rcomer
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DocumentationDocumentation: APIfiles in lib/ and doc/apifiles in lib/ and doc/apiGood first issueOpen a pull request against these issues if there are no active ones!Open a pull request against these issues if there are no active ones!