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`glob.glob()` currently calls itself recursively to build a list of matches of
the dirname part of the pattern and then filters by the basename part. This is
effectively BFS. ``glob.glob('*/*/*/*/*/foo')`` will build a huge list of all
directories 5 levels deep even if only a handful of them contain a ``foo``
entry. A generator-based recusion would never have to store these list at once
by implementing DFS. This patch converts the `glob` function to an `iglob`
recursive generator . `glob()` now just returns ``list(iglob(pattern))``.
I also cleaned up the code a bit (reduced duplicate `has_magic()` checks and
created a second `glob0` helper func so that the main loop need not be
duplicated).
Thanks to Cherniavsky Beni for the patch!
52 lines
1.8 KiB
TeX
52 lines
1.8 KiB
TeX
\section{\module{glob} ---
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\UNIX{} style pathname pattern expansion}
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\declaremodule{standard}{glob}
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\modulesynopsis{\UNIX\ shell style pathname pattern expansion.}
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The \module{glob} module finds all the pathnames matching a specified
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pattern according to the rules used by the \UNIX{} shell. No tilde
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expansion is done, but \code{*}, \code{?}, and character ranges
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expressed with \code{[]} will be correctly matched. This is done by
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using the \function{os.listdir()} and \function{fnmatch.fnmatch()}
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functions in concert, and not by actually invoking a subshell. (For
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tilde and shell variable expansion, use \function{os.path.expanduser()}
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and \function{os.path.expandvars()}.)
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\index{filenames!pathname expansion}
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\begin{funcdesc}{glob}{pathname}
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Return a possibly-empty list of path names that match \var{pathname},
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which must be a string containing a path specification.
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\var{pathname} can be either absolute (like
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\file{/usr/src/Python-1.5/Makefile}) or relative (like
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\file{../../Tools/*/*.gif}), and can contain shell-style wildcards.
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Broken symlinks are included in the results (as in the shell).
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\end{funcdesc}
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\begin{funcdesc}{iglob}{pathname}
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Return an iterator which yields the same values as \function{glob()}
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without actually storing them all simultaneously.
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\versionadded{2.5}
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\end{funcdesc}
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For example, consider a directory containing only the following files:
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\file{1.gif}, \file{2.txt}, and \file{card.gif}. \function{glob()}
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will produce the following results. Notice how any leading components
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of the path are preserved.
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\begin{verbatim}
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>>> import glob
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>>> glob.glob('./[0-9].*')
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['./1.gif', './2.txt']
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>>> glob.glob('*.gif')
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['1.gif', 'card.gif']
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>>> glob.glob('?.gif')
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['1.gif']
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\end{verbatim}
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\begin{seealso}
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\seemodule{fnmatch}{Shell-style filename (not path) expansion}
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\end{seealso}
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