other:python:jyp_steps
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other:python:jyp_steps [2016/01/21 16:43] jypeter More stuff |
other:python:jyp_steps [2016/01/22 11:40] jypeter added cdms2/netcdf4 |
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| ==== Python 2.7 ==== | ==== Python 2.7 ==== | ||
| - | [[https://docs.python.org/2.7/|html]] - [[https://docs.python.org/2.7/download.html|pdf]] | + | [[https://docs.python.org/2.7/|html]] - [[https://docs.python.org/2.7/download.html|pdf (in a zip file)]] |
| ==== Python 3 ==== | ==== Python 3 ==== | ||
| - | [[https://docs.python.org/3/|html]] - [[https://docs.python.org/3/download.html|pdf]] | + | [[https://docs.python.org/3/|html]] - [[https://docs.python.org/3/download.html|pdf (in a zip file)]] |
| + | |||
| + | |||
| + | ===== Numpy and Scipy ===== | ||
| + | |||
| + | Summary: Python provides //ordered// objects (e.g. lists, strings, basic arrays, ...) and some math operators, but you can't do real heavy computation with these. **Numpy** makes it possible to work with multi-dimensional data arrays, and using array syntax and masks (instead of explicit nested loops and tests) and the apropriate numpy functions will allow you to get performance similar to what you would get with a compiled program! **Scipy** adds more scientific functions | ||
| + | |||
| + | How to get started? | ||
| + | - always remember that indices start at ''0'' and that the last element of an array is at index ''-1''! Learn about indexing and slicing by manipulating a string (try '''This document by JY is awesome!'[::-1]'') | ||
| + | - read the [[https://docs.scipy.org/doc/numpy-dev/user/quickstart.html|Quickstart tutorial]] | ||
| + | - have a quick look at the full documentation to know where things are | ||
| + | - Numpy User Guide: | ||
| + | - Numpy Reference Guide | ||
| + | - Scipy Reference Guide | ||
| + | |||
| + | ===== cdms2 and netcdf4 ===== | ||
| + | |||
| + | There is a good chance that your input array data will come from a file in the [[http://www.unidata.ucar.edu/software/netcdf/|NetCDF]] format. Depending on which [[other:python:starting#some_python_distributions|python distribution]] you are using, you can use the //cdms2// or or //netCDF4// modules to read the data. | ||
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| + | Note: the NetCDF file format is self-documented, and the metadata of climate date files often follows the [[http://cfconventions.org/|CF (Climate and Forecast) Metadata Conventions]] | ||
| + | |||
| + | ==== cdms2 ==== | ||
| + | |||
| + | Summary: cdms2 can read/write netCDF files (and read //grads// dat+ctl files) and provides a higher level interface than netCDF4. Unfortunately, cdms2 is only available in the UV-CDAT distribution, and distributions where somebody has installed some version of //cdat-lite//. When you can use cdms2, you also have access to //cdtime//, that is very useful for handling time axis data. | ||
| + | |||
| + | How to get started: | ||
| + | - read [[http://www.lsce.ipsl.fr/Phocea/file.php?class=page&file=5/pythonCDAT_jyp_2sur2_070306.pdf|JYP's cdms tutorial]], starting at page 54 | ||
| + | - the tutorial is in French (soooorry!) | ||
| + | - you have to replace //cdms// with **cdms2**, and //MV// with **MV2** (sooorry about that, the tutorial was written when CDAT was based on Numeric instead of numpy to handle array data) | ||
| + | - read the [[http://uv-cdat.llnl.gov/documentation/cdms/cdms.html|official cdms documentation]] | ||
| + | - ask questions and get answers on the [[http://uvcdat.askbot.com/questions/|UV-CDAT askbot]] | ||
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| + | |||
| + | ==== netCDF4 ==== | ||
| + | |||
| + | Summary: netCDF4 can read/write netCDF files and is available in most python distributions | ||
| + | |||
| + | Where: [[http://unidata.github.io/netcdf4-python/]] | ||
| ===== Matplotlib ===== | ===== Matplotlib ===== | ||
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| ===== Quick Reference ===== | ===== Quick Reference ===== | ||
| - | * The nice 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]] |
| ===== Some good coding tips ===== | ===== Some good coding tips ===== | ||
other/python/jyp_steps.txt · Last modified: 2024/03/07 10:15 by jypeter
