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other:python:jyp_steps [2018/07/10 11:02]
jypeter [json files] Moved json to a new "Data file formats" section, and dded LiPD and BagIt
other:python:jyp_steps [2018/10/18 17:57] (current)
jypeter [Misc numpy tricks]
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     - [[https://​docs.scipy.org/​doc/​numpy-dev/​user/​numpy-for-matlab-users.html|Numpy for Matlab users]]     - [[https://​docs.scipy.org/​doc/​numpy-dev/​user/​numpy-for-matlab-users.html|Numpy for Matlab users]]
     - [[http://​mathesaurus.sourceforge.net/​matlab-numpy.html|NumPy for MATLAB users]] (nice, but does not seem to be maintained any more)     - [[http://​mathesaurus.sourceforge.net/​matlab-numpy.html|NumPy for MATLAB users]] (nice, but does not seem to be maintained any more)
-  - read the [[https://​docs.scipy.org/​doc/​numpy-dev/​user/​quickstart.html|Quickstart tutorial]]+  - read the really nice [[https://​docs.scipy.org/​doc/​numpy/​user/​quickstart.html|numpy Quickstart tutorial]]
   - have a quick look at the full documentation to know where things are   - have a quick look at the full documentation to know where things are
     - Numpy User Guide     - Numpy User Guide
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        [20, 21, -1, -1, 24, 25, 26, 27, 28, 29]])        [20, 21, -1, -1, 24, 25, 26, 27, 28, 29]])
 </​code></​note>​ </​code></​note>​
 +
 +==== Extra numpy information ====
 +
 +  * More information about array indexing:
 +    * Examples:
 +      * {{ :​other:​python:​indirect_indexing_2.py.txt |}}: Take a vertical slice in a 3D zyx array, along a varying y '​path'​
 +    * [[https://​docs.scipy.org/​doc/​numpy/​user/​basics.indexing.html|Indexing]] (//index arrays//, //boolean index arrays//, //​np.newaxis//,​ //​Ellipsis//,​ //variable numbers of indices//, ...)
 +    * [[https://​docs.scipy.org/​doc/​numpy/​user/​quickstart.html#​fancy-indexing-and-index-tricks|Fancy indexing]] and [[https://​docs.scipy.org/​doc/​numpy/​user/​quickstart.html#​the-ix-function|the ix_() function]]
 +    * [[https://​docs.scipy.org/​doc/​numpy/​reference/​arrays.indexing.html|Indexing (in the numpy reference manual)]]
 +    * [[https://​docs.scipy.org/​doc/​numpy/​reference/​routines.indexing.html#​routines-indexing|Indexing routines]] ​
 +  * More information about arrays:
 +    * [[https://​docs.scipy.org/​doc/​numpy/​reference/​routines.array-creation.html#​routines-array-creation|Array creation routines]]
 +    * [[https://​docs.scipy.org/​doc/​numpy/​reference/​routines.array-manipulation.html|Array manipulation routines]]
 +    * [[https://​docs.scipy.org/​doc/​numpy/​reference/​maskedarray.html|Masked arrays]]
 +      * [[https://​docs.scipy.org/​doc/​numpy/​reference/​routines.ma.html|Masked array operations]]
 +  * [[https://​docs.scipy.org/​doc/​numpy/​user/​misc.html#​ieee-754-floating-point-special-values|Dealing with special numerical values]] (//Nan//, //inf//)
 +    * If you know that your data has missing values, it is cleaner and safer to handle them with [[https://​docs.scipy.org/​doc/​numpy/​reference/​maskedarray.html|masked arrays]]!
 +    * [[https://​docs.scipy.org/​doc/​numpy/​user/​misc.html#​how-numpy-handles-numerical-exceptions|Handling numerical exceptions]]
 +    * [[https://​docs.scipy.org/​doc/​numpy/​reference/​routines.err.html|Floating point error handling]]
  
 ===== cdms2 and netCDF4 ===== ===== cdms2 and netCDF4 =====
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     - a Matplotlib //Axis// is a plot inside a Figure... [[http://​matplotlib.org/​faq/​usage_faq.html#​parts-of-a-figure|More details]]     - a Matplotlib //Axis// is a plot inside a Figure... [[http://​matplotlib.org/​faq/​usage_faq.html#​parts-of-a-figure|More details]]
     - some examples are more //​pythonic//​ (ie object oriented) than others, some example mix different styles of coding, all this can be confusing. Try to [[http://​matplotlib.org/​faq/​usage_faq.html#​coding-styles|use an object oriented way of doing things]]!     - some examples are more //​pythonic//​ (ie object oriented) than others, some example mix different styles of coding, all this can be confusing. Try to [[http://​matplotlib.org/​faq/​usage_faq.html#​coding-styles|use an object oriented way of doing things]]!
 +    - it may be hard to (remember how to) work with colors. Some examples from the [[http://​matplotlib.org/​gallery.html|Gallery]] can help you!
 +      * [[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/​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/​examples/​color/​named_colors.html|named_colors.py]]:​ named colors
 +      * More details about the colors below, in the [[#​graphics_related_resources|Resources section]]
     - sometimes the results of the python/​matplolib commands are displayed directly, sometimes not. It depends if you are in [[http://​matplotlib.org/​faq/​usage_faq.html#​what-is-interactive-mode|interactive or non-interactive]] mode     - sometimes the results of the python/​matplolib commands are displayed directly, sometimes not. It depends if you are in [[http://​matplotlib.org/​faq/​usage_faq.html#​what-is-interactive-mode|interactive or non-interactive]] mode
     - the documentation may mention [[http://​matplotlib.org/​faq/​usage_faq.html#​what-is-a-backend|backends]]. What?? Basically, you use python commands to create a plot, and the backend is the //thing// that will render your plot on the screen or in a file (png, pdf, etc...)     - the documentation may mention [[http://​matplotlib.org/​faq/​usage_faq.html#​what-is-a-backend|backends]]. What?? Basically, you use python commands to create a plot, and the backend is the //thing// that will render your plot on the screen or in a file (png, pdf, etc...)
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   - Read the [[http://​www.labri.fr/​perso/​nrougier/​teaching/​matplotlib/​|Matplotlib tutorial by Nicolas Rougier]]   - Read the [[http://​www.labri.fr/​perso/​nrougier/​teaching/​matplotlib/​|Matplotlib tutorial by Nicolas Rougier]]
   - Download the [[http://​matplotlib.org/​contents.html|pdf version of the manual]]. **Do not print** the 2800+ pages of the manual! Read the beginner'​s guide (Chapter //FIVE// of //Part II//) and have a super quick look at the table of contents of the whole document.   - Download the [[http://​matplotlib.org/​contents.html|pdf version of the manual]]. **Do not print** the 2800+ pages of the manual! Read the beginner'​s guide (Chapter //FIVE// of //Part II//) and have a super quick look at the table of contents of the whole document.
 +
 +==== Misc Matplotlib tricks ====
 +
 +  * Specifying the background color of a plot (e.g. when plotting a masked variable and you don't want the masked areas to be white)
 +    * ''#​ make the background dark gray (call this before the contourf)''​\\ ''​plt.gca().patch.set_color('​.25'​)''​\\ ''​plt.contourf(d)''​\\ ''​plt.show()''​
 +    * [[https://​stackoverflow.com/​questions/​9797520/​masking-part-of-a-contourf-plot-in-matplotlib|trick source]]
  
 ===== Graphics related resources ===== ===== Graphics related resources =====
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 Help on //stack overflow//: [[https://​stackoverflow.com/​questions/​tagged/​cartopy|cartopy help]] Help on //stack overflow//: [[https://​stackoverflow.com/​questions/​tagged/​cartopy|cartopy help]]
 +
 +===== Maps and projections resources =====
 +
 +==== About projections ====
 +
 +  * [[https://​egsc.usgs.gov/​isb//​pubs/​MapProjections/​projections.html|Map projections from USGS poster]]
 +  * [[https://​pubs.usgs.gov/​pp/​1395/​report.pdf|Map projections - A working manual (USGS)]]
 +
 +==== Libraries ====
 +
 +  * Projections in vcs
 +  * [[http://​matplotlib.org/​basemap/​users/​mapsetup.html|Projections in basemap]]
 +  * [[https://​scitools.org.uk/​cartopy/​docs/​latest/​crs/​projections.html|Projections in cartopy]]
 +
  
 ===== 3D resources ===== ===== 3D resources =====
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   * The nice and convenient Python 2.7 Quick Reference: [[http://​rgruet.free.fr/​PQR27/​PQR2.7_printing_a4.pdf|pdf]] - [[http://​rgruet.free.fr/​PQR27/​PQR2.7.html|html]]   * The nice and convenient Python 2.7 Quick Reference: [[http://​rgruet.free.fr/​PQR27/​PQR2.7_printing_a4.pdf|pdf]] - [[http://​rgruet.free.fr/​PQR27/​PQR2.7.html|html]]
 +    * A possibly more [[http://​iysik.com/​PQR2.7/​PQR2.7.html|up-date-version]]
 +
 +  * Python 3 [[https://​perso.limsi.fr/​pointal/​python:​abrege|Quick reference]] and [[https://​perso.limsi.fr/​pointal/​python:​memento|Cheat sheet]]
 +
 +===== Misc tutorials =====
  
 +  * [[https://​pyformat.info/​|PyFormat]]:​ //With this site we try to show you the most common use-cases covered by the old and new style string formatting API with practical examples//
 ===== Some good coding tips ===== ===== Some good coding tips =====
  
other/python/jyp_steps.1531213330.txt.gz · Last modified: 2018/07/10 11:02 by jypeter