Differences

This shows you the differences between two versions of the page.

--- other:python:jyp_steps [2019/07/11 17:28] – [Pandas] re-organized the cheat sheets and tutorials jypeter
+++ other:python:jyp_steps [2019/08/27 11:07] – [Useful matplotlib reference pages] Added cmap information jypeter
@@ Line 238: / Line 238: @@
       * ''my_page.savefig('my_plot.png', dpi=200, transparent=True, bbox_inches='tight')'': save the figure to a png file at a higher resolution than the default (default is 100 dots per inch), with a transparent background and no extra space around the figure
     - **display** the figure and its plots, and **start interacting** (zooming, panning...) with them:\\ ''plt.show()''
-    - it may be hard to (remember how to) **work with colors**. Some examples from the [[https://matplotlib.org/gallery/index.html]] can help you!
+    - it may be hard to (remember how to) **work with colors //and colorbars//**. Some examples from the [[https://matplotlib.org/gallery/index.html|matplotlib Gallery]] can help you!\\ Note: A **reversed version of each colormap** is available by appending ''_r'' to the name, e.g., ''viridis_r''
-      * [[https://matplotlib.org/examples/pylab_examples/leftventricle_bulleye.html|leftventricle_bulleye.py]]: associating different types of colormaps to a plot and colorbar
+      * [[https://matplotlib.org/gallery/specialty_plots/leftventricle_bulleye.html|leftventricle_bulleye.py]]: associating different types of colormaps to a plot and colorbar
       * [[https://matplotlib.org/examples/api/colorbar_only.html|colorbar_only.py]]: the different types of colorbars (or plotting only a colorbar)
-      * [[https://matplotlib.org/examples/color/colormaps_reference.html|colormaps_reference.py]]: pre-defined colormaps
+      * [[https://matplotlib.org/gallery/color/colormap_reference.html|colormaps_reference.py]]: pre-defined colormaps
-      * [[https://matplotlib.org/examples/color/named_colors.html|named_colors.py]]: named colors
+      * [[https://matplotlib.org/gallery/color/named_colors.html|named_colors.py]]: named colors
-      * More details about the colors below, in the [[#graphics_related_resources|Resources section]]
+      * More details about colors and colorbars below, in the [[#useful_matplotlib_reference_pages|Useful matplotlib reference pages]] section and the [[#graphics_related_resources|Graphics related resources]] section
     - if you don't see a part of what you have plotted, maybe it's hidden behind other elements! Use the [[https://matplotlib.org/examples/pylab_examples/zorder_demo.html|zorder parameter]] to explicitly **specify the plotting order/layers/depth**
       * things should automatically work //as expected// if //zorder// is not explicitly specified
@@ Line 286: / Line 286: @@
     * [[https://matplotlib.org/examples/color/named_colors.html|named colors]]
     * Reverting the colors: add ''_r'' at the end of the colormap name
+    * Number of colors in the //my_cmap// colormap (usually 256): ''my_cmap.N''
+      * Accessing the RGB color definition by index, from ''0'' to ''my_cmap.N - 1''. Note that the index will //saturate// below ''0'' and above ''my_cmap.N - 1''\\ <code>>>> my_cmap.N
+>>> my_cmap(-1) # Same as ano_cmap(0)
+(0.3686274509803922, 0.30980392156862746, 0.6352941176470588, 1.0)
+>>> my_cmap(0)
+(0.3686274509803922, 0.30980392156862746, 0.6352941176470588, 1.0)
+>>> my_cmap(1)
+(0.36186082276047676, 0.3185697808535179, 0.6394463667820068, 1.0)
+>>> my_cmap(255)
+(0.6196078431372549, 0.00392156862745098, 0.25882352941176473, 1.0)
+>>> my_cmap(256) # Same as ano_cmap(255)
+(0.6196078431372549, 0.00392156862745098, 0.25882352941176473, 1.0)
+>>> my_cmap(257) # Same as ano_cmap(255)
+(0.6196078431372549, 0.00392156862745098, 0.25882352941176473, 1.0)
+</code>
     * Special colormap colors
-      * ''cmap.set_bad(color='k')'': color to be used for masked values
+      * ''my_cmap.set_bad(color='k')'': color to be used for **masked** values
-      * ''cmap.set_over(color='k')'': color to be used for high out-of-range values
+      * ''my_cmap.set_over(color='k')'': color to be used for //high out-of-range values//
-      * ''cmap.set_under(color='k')'': color to be used for low out-of-range values
+      * ''my_cmap.set_under(color='k')'': color to be used for //low out-of-range values//
-  * [[https://matplotlib.org/api/_as_gen/matplotlib.figure.Figure.html#matplotlib.figure.Figure.colorbar|colorbar]] and ([[https://matplotlib.org/gallery/images_contours_and_fields/contourf_demo.html|contourf + colorbar demo]])
+  * [[https://matplotlib.org/api/_as_gen/matplotlib.figure.Figure.html#matplotlib.figure.Figure.colorbar|colorbar]]
+    * [[https://matplotlib.org/gallery/subplots_axes_and_figures/colorbar_placement.html|Placing colorbars demo]]
+    * [[https://matplotlib.org/gallery/images_contours_and_fields/contourf_demo.html|contourf + colorbar demo]]
   * [[https://matplotlib.org/api/_as_gen/matplotlib.pyplot.text.html|text(...)]] and [[https://matplotlib.org/tutorials/text/annotations.html|annotations]]
     * Some titles: