Quickly plot colormap or a color palette with matplotlib

I present here simple convenient functions to plot a matplotlib colormap or a color palette.

The source codes of the functions are available on this gist.

For colormaps

You can use either its name or the matplotlib.cm.colormap object.

This is how to use the function :

fig = plot_cmap("summer", 6)

fig = plot_cmap(plt.cm.summer, 6)

And you will get :

The source code

import matplotlib.pyplot as plt
 
def plot_cmap(cmap, ncolor):
    """ 
    A convenient function to plot colors of a matplotlib cmap
 
    Args:
        ncolor (int): number of color to show
        cmap: a cmap object or a matplotlib color name
    """
 
    if isinstance(cmap, str):
        try:
            cm = plt.get_cmap(cmap)
        except ValueError:
            print("WARNINGS :", cmap, " is not a known colormap")
            cm = plt.cm.gray
    else:
        cm = cmap
 
    with mpl.rc_context(mpl.rcParamsDefault):
        fig = plt.figure(figsize=(6, 1), frameon=False)
        ax = fig.add_subplot(111)
        ax.pcolor(np.linspace(1, ncolor, ncolor).reshape(1, ncolor), cmap=cm)
        ax.set_title(cm.name)
        xt = ax.set_xticks([])
        yt = ax.set_yticks([])
    return fig

For a list of colors

This is how to use the function :

colors = ["#9b59b6", "#3498db", "#95a5a6", "#e74c3c", "#34495e", "#2ecc71"]
show_colors(colors)

And you will simply get a square for each color :

The source code

import matplotlib.pyplot as plt
 
def show_colors(colors):
    """
    Draw a square for each color contained in the colors list
    given in argument.
    """
    with plt.rc_context(plt.rcParamsDefault):
        fig = plt.figure(figsize=(6, 1), frameon=False)
        ax = fig.add_subplot(111)
        for x, color in enumerate(colors):
            ax.add_patch(
                mpl.patches.Rectangle(
                    (x, 0), 1, 1, facecolor=color
                )
            )
        ax.set_xlim((0, len(colors)))
        ax.set_ylim((0, 1))
        ax.set_xticks([])
        ax.set_yticks([])
        ax.set_aspect("equal")
 
    return fig

Quickly plot colormap or a color palette with matplotlib

For colormaps

The source code

For a list of colors

The source code

Color scale and color maps with python

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