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Overview
In an earlier post "OS.walk in Python", I described how to use os.walk and showed some examples on how to use it in scripts.
In this article, I will show how to use the os.walk() module function to walk a
directory tree, and the fnmatch module for matching file names.
What is OS.walk?
It generates the file names in a directory tree by walking the tree either
top-down or bottom-up.
For each directory in the tree rooted at directory top (including top itself),
it yields a 3-tuple (dirpath, dirnames, filenames).
dirpath # is a string, the path to the directory.
dirnames # is a list of the names of the subdirectories in dirpath
(excluding '.' and '..').
filenames # is a list of the names of the non-directory files in dirpath.
Note that the names in the lists contain no path components.
To get a full path (which begins with top) to a file or directory in dirpath,
do os.path.join(dirpath, name).
For more information, please see the Python Docs.
What is Fnmatch
The fnmatch module compares file names against glob-style patterns such as used
by Unix shells.
These are not the same as the more sophisticated regular expression rules.
It's purely a string matching operation.
If you find it more convenient to use a different pattern style, for example
regular expressions, then simply use regex operations to match your filenames.
http://www.doughellmann.com/PyMOTW/fnmatch/
What does it do?
The fnmatch module is used for the wild-card pattern matching.
Simple Matching
fnmatch() compares a single file name against a pattern and returns a boolean
indicating whether or not they match.
The comparison is case-sensitive when the operating system uses a case-sensitive
file system.
Filtering
To test a sequence of filenames, you can use filter().
It returns a list of the names that match the pattern argument.
In an earlier post "OS.walk in Python", I described how to use os.walk and showed some examples on how to use it in scripts.
In this article, I will show how to use the os.walk() module function to walk a
directory tree, and the fnmatch module for matching file names.
What is OS.walk?
It generates the file names in a directory tree by walking the tree either
top-down or bottom-up.
For each directory in the tree rooted at directory top (including top itself),
it yields a 3-tuple (dirpath, dirnames, filenames).
dirpath # is a string, the path to the directory.
dirnames # is a list of the names of the subdirectories in dirpath
(excluding '.' and '..').
filenames # is a list of the names of the non-directory files in dirpath.
Note that the names in the lists contain no path components.
To get a full path (which begins with top) to a file or directory in dirpath,
do os.path.join(dirpath, name).
For more information, please see the Python Docs.
What is Fnmatch
The fnmatch module compares file names against glob-style patterns such as used
by Unix shells.
These are not the same as the more sophisticated regular expression rules.
It's purely a string matching operation.
If you find it more convenient to use a different pattern style, for example
regular expressions, then simply use regex operations to match your filenames.
http://www.doughellmann.com/PyMOTW/fnmatch/
What does it do?
The fnmatch module is used for the wild-card pattern matching.
Simple Matching
fnmatch() compares a single file name against a pattern and returns a boolean
indicating whether or not they match.
The comparison is case-sensitive when the operating system uses a case-sensitive
file system.
Filtering
To test a sequence of filenames, you can use filter().
It returns a list of the names that match the pattern argument.
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import fnmatch import os ############################################ # Find all mp3 files # # # # This script will search for *.mp3 # # files from the rootPath ("/") # # # ############################################ rootPath = '/' pattern = '*.mp3' for root, dirs, files in os.walk(rootPath): for filename in fnmatch.filter(files, pattern): print( os.path.join(root, filename)) ############################################ # Search computer for specific files # # # # This script uses 'os.walk' and # # 'fnmatch' with filters to search # # the hard-drive for all image files # # # ############################################ images = ['*.jpg', '*.jpeg', '*.png', '*.tif', '*.tiff'] matches = [] for root, dirnames, filenames in os.walk("C:\\"): for extensions in images: for filename in fnmatch.filter(filenames, extensions): matches.append(os.path.join(root, filename))
URL: http://www.pythonforbeginners.com/systems-programming/os-walk-and-fnmatch-in-python/