title: cmaps vs plt.style.use. What's the difference?
body: <p>I noticed that there are two ways to change the themes of a plot in matplotlib:</p>
  
  <p>1) type the style before the plot: eg:</p>
  
  <pre><code>plt.style.use("seaborn-darkgrid")
  </code></pre>
  
  <p>2) using the 'cmap = "seismic"' inside the scatter plot arguments.
  eg: </p>
  
  <pre><code>scatter1 = ax.scatter(df["age"],df["alpha"], c = df["beta"],cmap = "seismic")
  </code></pre>
  
  <p>I get an error when I try to use cmap = "seaborn-darkgrid" with this error message:</p>
  
  <pre><code>ValueError: Colormap seaborn-darkgrid is not recognized. Possible values are: Accent, Accent_r, Blues, Blues_r, BrBG, BrBG_r, BuGn, BuGn_r, BuPu, BuPu_r, CMRmap, CMRmap_r, Dark2, Dark2_r, GnBu, GnBu_r, Greens, Greens_r, Greys, Greys_r, OrRd, OrRd_r, Oranges, Oranges_r, PRGn, PRGn_r, Paired, Paired_r, Pastel1, Pastel1_r, Pastel2, Pastel2_r, PiYG, PiYG_r, PuBu, PuBuGn, PuBuGn_r, PuBu_r, PuOr, PuOr_r, PuRd, PuRd_r, Purples, Purples_r, RdBu, RdBu_r, RdGy, RdGy_r, RdPu, RdPu_r, RdYlBu, RdYlBu_r, RdYlGn, RdYlGn_r, Reds, Reds_r, Set1, Set1_r, Set2, Set2_r, Set3, Set3_r, Spectral, Spectral_r, Wistia, Wistia_r, YlGn, YlGnBu, YlGnBu_r, YlGn_r, YlOrBr, YlOrBr_r, YlOrRd, YlOrRd_r, afmhot, afmhot_r, autumn, autumn_r, binary, binary_r, bone, bone_r, brg, brg_r, bwr, bwr_r, cividis, cividis_r, cool, cool_r, coolwarm, coolwarm_r, copper, copper_r, cubehelix, cubehelix_r, flag, flag_r, gist_earth, gist_earth_r, gist_gray, gist_gray_r, gist_heat, gist_heat_r, gist_ncar, gist_ncar_r, gist_rainbow, gist_rainbow_r, gist_stern, gist_stern_r, gist_yarg, gist_yarg_r, gnuplot, gnuplot2, gnuplot2_r, gnuplot_r, gray, gray_r, hot, hot_r, hsv, hsv_r, inferno, inferno_r, jet, jet_r, magma, magma_r, nipy_spectral, nipy_spectral_r, ocean, ocean_r, pink, pink_r, plasma, plasma_r, prism, prism_r, rainbow, rainbow_r, seismic, seismic_r, spring, spring_r, summer, summer_r, tab10, tab10_r, tab20, tab20_r, tab20b, tab20b_r, tab20c, tab20c_r, terrain, terrain_r, twilight, twilight_r, twilight_shifted, twilight_shifted_r, viridis, viridis_r, winter, winter_r
  </code></pre>
  
  <p>Why can I use 'seaborn-darkgrid' using the 'plt.style.use("seaborn-darkgrid")', but not the cmap method (without stating the obvious!)? Are there two completely separate sets of styles in matplotlib library? One being the cmaps, and the other the plt.styles? Sounds like they are completely distinct in the back end code?</p>
  
  <p>Thanks. </p>