plt.scatter(np.arange(10),np.arange(10),c="0.5")

---------------------------------------------------------------------------IndexError                                Traceback (most recent call last)<ipython-input-99-426550bf20a7> in <module>()----> 1 plt.scatter(np.arange(10), np.arange(10), c="0.5")~/anaconda3/lib/python3.6/site-packages/matplotlib/pyplot.py in scatter(x, y, s, c, marker, cmap, norm, vmin, vmax, alpha, linewidths, verts, edgecolors, data, **kwargs)   2791         x=x, y=y, s=s, c=c, marker=marker, cmap=cmap, norm=norm,   2792         vmin=vmin, vmax=vmax, alpha=alpha, linewidths=linewidths,-> 2793         verts=verts, edgecolors=edgecolors, data=data, **kwargs)   2794     sci(__ret)   2795     return __ret~/anaconda3/lib/python3.6/site-packages/matplotlib/__init__.py in inner(ax, data, *args, **kwargs)   1783                         "the Matplotlib list!)" % (label_namer, func.__name__),   1784                         RuntimeWarning, stacklevel=2)-> 1785             return func(ax, *args, **kwargs)   1786    1787         inner.__doc__ = _add_data_doc(inner.__doc__,~/anaconda3/lib/python3.6/site-packages/matplotlib/axes/_axes.py in scatter(self, x, y, s, c, marker, cmap, norm, vmin, vmax, alpha, linewidths, verts, edgecolors, **kwargs)   4187             try:  # First, does 'c' look suitable for value-mapping?   4188                 c_array = np.asanyarray(c, dtype=float)-> 4189                 n_elem = c_array.shape[0]   4190                 if c_array.shape in xy_shape:   4191                     c = np.ma.ravel(c_array)IndexError: tuple index out of range

plt.scatter(np.arange(10),np.arange(10),c=(0.5,0.5,0.5))