other:python:misc_by_jyp
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other:python:misc_by_jyp [2023/09/27 13:53] jypeter Added a section with a link to "100 numpy exercises" |
other:python:misc_by_jyp [2023/11/29 10:32] jypeter [Working with paths and filenames] Improved and added pathlib example |
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| ==== Working with paths and filenames ==== | ==== Working with paths and filenames ==== | ||
| - | If you are in a hurry, you can just use string functions to work with path and file names. But you will need some specific functions to check if a file exists, and similar operations. All these are available in 2 libraries that have similar functions. Both of these libraries can deal with Unix-type paths on Linux computers, and Windows-type paths on Windows computers | + | If you are in a hurry, you can just use string functions to work with paths and file names. |
| - | * [[https://docs.python.org/3/library/os.path.html|os.path]] //Common pathname manipulations// | + | |
| + | You will need some specific objects and functions to check if a file exists, and similar operations. Check the libraries listed below, that can automatically deal with Unix-type paths on Linux and MacOS computers, and Windows-type paths on Windows computers | ||
| + | |||
| + | * [[https://docs.python.org/3/library/os.path.html|os.path]]: //common pathname manipulations// | ||
| * Available since... a long time! Use this if you want to avoid backward compatibility problems | * Available since... a long time! Use this if you want to avoid backward compatibility problems | ||
| * Some functions are directly in [[https://docs.python.org/3/library/os.html|os]] //Miscellaneous operating system interfaces//\\ e.g. [[https://docs.python.org/3/library/os.html#os.remove|os.remove]] and [[https://docs.python.org/3/library/os.html#os.rmdir|os.rmdir]] | * Some functions are directly in [[https://docs.python.org/3/library/os.html|os]] //Miscellaneous operating system interfaces//\\ e.g. [[https://docs.python.org/3/library/os.html#os.remove|os.remove]] and [[https://docs.python.org/3/library/os.html#os.rmdir|os.rmdir]] | ||
| - | * [[https://docs.python.org/3/library/pathlib.html|pathlib]] //Object-oriented filesystem paths// | + | * [[https://docs.python.org/3/library/pathlib.html|pathlib]]: a **more recent** //object-oriented// way to deal with //filesystem paths// |
| * Available since Python version 3.4 | * Available since Python version 3.4 | ||
| * [[https://docs.python.org/3/library/pathlib.html#correspondence-to-tools-in-the-os-module|Matching pathlib, and os or os.path functions]] | * [[https://docs.python.org/3/library/pathlib.html#correspondence-to-tools-in-the-os-module|Matching pathlib, and os or os.path functions]] | ||
| - | * [[https://docs.python.org/3/library/shutil.html|High-level file operations]] | + | * [[https://docs.python.org/3/library/shutil.html|shutil]]: High-level file operations, e.g copy/move a file or directory tree |
| - | === Example: getting the full path of the Python used === | + | === Example: getting the full path of the Python executable used === |
| Note: the actual python may be different from the default python! | Note: the actual python may be different from the default python! | ||
| Line 83: | Line 86: | ||
| /usr/bin/python | /usr/bin/python | ||
| - | $ /modfs/modtools/miniconda3//envs/analyse_3.6_test/bin/python | + | $ /home/share/unix_files/cdat/miniconda3_21-02/envs/cdatm_py3/bin/python |
| >>> import sys, shutil | >>> import sys, shutil | ||
| >>> shutil.which('python') | >>> shutil.which('python') | ||
| '/usr/bin/python' | '/usr/bin/python' | ||
| >>> sys.executable | >>> sys.executable | ||
| - | '/modfs/modtools/miniconda3//envs/analyse_3.6_test/bin/python'</code> | + | '/home/share/unix_files/cdat/miniconda3_21-02/envs/cdatm_py3/bin/python'</code> |
| Line 104: | Line 107: | ||
| </code> | </code> | ||
| + | |||
| + | === Example: system independent paths with pathlib === | ||
| + | |||
| + | Note: the following example was generated on a Linux server and uses a <wrap em>/</wrap> character as a path separator | ||
| + | |||
| + | <code>>>> my_home = Path.home() | ||
| + | >>> my_home | ||
| + | PosixPath('/home/users/my_login') | ||
| + | >>> my_conf = my_home / '.config' / 'evince' | ||
| + | >>> my_conf | ||
| + | PosixPath('/home/users/my_login/.config/evince') | ||
| + | >>> my_conf.is_dir() | ||
| + | True | ||
| + | >>> my_conf.is_file() | ||
| + | False | ||
| + | >>> list(my_conf.glob('*')) | ||
| + | [PosixPath('/home/users/my_login/.config/evince/evince_toolbar.xml'), PosixPath(' /home/users/my_login/.config/evince/accels')] | ||
| + | >>> [ ff.name for ff in my_conf.glob('*') ] | ||
| + | ['evince_toolbar.xml', 'accels'] | ||
| + | </code> | ||
| === Example: getting the size(s) of all the files in a directory === | === Example: getting the size(s) of all the files in a directory === | ||
other/python/misc_by_jyp.txt · Last modified: 2024/04/19 12:02 by jypeter
