Python recursive folder read
PythonScriptingFile IoPython Problem Overview
I have a C++/Obj-C background and I am just discovering Python (been writing it for about an hour). I am writing a script to recursively read the contents of text files in a folder structure.
The problem I have is the code I have written will only work for one folder deep. I can see why in the code (see #hardcoded path), I just don't know how I can move forward with Python since my experience with it is only brand new.
Python Code:
import os
import sys
rootdir = sys.argv[1]
for root, subFolders, files in os.walk(rootdir):
for folder in subFolders:
outfileName = rootdir + "/" + folder + "/py-outfile.txt" # hardcoded path
folderOut = open( outfileName, 'w' )
print "outfileName is " + outfileName
for file in files:
filePath = rootdir + '/' + file
f = open( filePath, 'r' )
toWrite = f.read()
print "Writing '" + toWrite + "' to" + filePath
folderOut.write( toWrite )
f.close()
folderOut.close()
Python Solutions
Solution 1 - Python
Make sure you understand the three return values of os.walk:
for root, subdirs, files in os.walk(rootdir):
has the following meaning:
root: Current path which is "walked through"subdirs: Files inrootof type directoryfiles: Files inroot(not insubdirs) of type other than directory
And please use os.path.join instead of concatenating with a slash! Your problem is filePath = rootdir + '/' + file - you must concatenate the currently "walked" folder instead of the topmost folder. So that must be filePath = os.path.join(root, file). BTW "file" is a builtin, so you don't normally use it as variable name.
Another problem are your loops, which should be like this, for example:
import os
import sys
walk_dir = sys.argv[1]
print('walk_dir = ' + walk_dir)
# If your current working directory may change during script execution, it's recommended to
# immediately convert program arguments to an absolute path. Then the variable root below will
# be an absolute path as well. Example:
# walk_dir = os.path.abspath(walk_dir)
print('walk_dir (absolute) = ' + os.path.abspath(walk_dir))
for root, subdirs, files in os.walk(walk_dir):
print('--\nroot = ' + root)
list_file_path = os.path.join(root, 'my-directory-list.txt')
print('list_file_path = ' + list_file_path)
with open(list_file_path, 'wb') as list_file:
for subdir in subdirs:
print('\t- subdirectory ' + subdir)
for filename in files:
file_path = os.path.join(root, filename)
print('\t- file %s (full path: %s)' % (filename, file_path))
with open(file_path, 'rb') as f:
f_content = f.read()
list_file.write(('The file %s contains:\n' % filename).encode('utf-8'))
list_file.write(f_content)
list_file.write(b'\n')
If you didn't know, the with statement for files is a shorthand:
with open('filename', 'rb') as f:
dosomething()
# is effectively the same as
f = open('filename', 'rb')
try:
dosomething()
finally:
f.close()
Solution 2 - Python
If you are using Python 3.5 or above, you can get this done in 1 line.
import glob
# root_dir needs a trailing slash (i.e. /root/dir/)
for filename in glob.iglob(root_dir + '**/*.txt', recursive=True):
print(filename)
As mentioned in the documentation
> If recursive is true, the pattern '**' will match any files and zero or more directories and subdirectories.
If you want every file, you can use
import glob
for filename in glob.iglob(root_dir + '**/**', recursive=True):
print(filename)
Solution 3 - Python
Agree with Dave Webb, os.walk will yield an item for each directory in the tree. Fact is, you just don't have to care about subFolders.
Code like this should work:
import os
import sys
rootdir = sys.argv[1]
for folder, subs, files in os.walk(rootdir):
with open(os.path.join(folder, 'python-outfile.txt'), 'w') as dest:
for filename in files:
with open(os.path.join(folder, filename), 'r') as src:
dest.write(src.read())
Solution 4 - Python
TL;DR: This is the equivalent to find -type f to go over all files in all folders below and including the current one:
for currentpath, folders, files in os.walk('.'):
for file in files:
print(os.path.join(currentpath, file))
As already mentioned in other answers, os.walk() is the answer, but it could be explained better. It's quite simple! Let's walk through this tree:
docs/
└── doc1.odt
pics/
todo.txt
With this code:
for currentpath, folders, files in os.walk('.'):
print(currentpath)
The currentpath is the current folder it is looking at. This will output:
.
./docs
./pics
So it loops three times, because there are three folders: the current one, docs, and pics. In every loop, it fills the variables folders and files with all folders and files. Let's show them:
for currentpath, folders, files in os.walk('.'):
print(currentpath, folders, files)
This shows us:
# currentpath folders files
. ['pics', 'docs'] ['todo.txt']
./pics [] []
./docs [] ['doc1.odt']
So in the first line, we see that we are in folder ., that it contains two folders namely pics and docs, and that there is one file, namely todo.txt. You don't have to do anything to recurse into those folders, because as you see, it recurses automatically and just gives you the files in any subfolders. And any subfolders of that (though we don't have those in the example).
If you just want to loop through all files, the equivalent of find -type f, you can do this:
for currentpath, folders, files in os.walk('.'):
for file in files:
print(os.path.join(currentpath, file))
This outputs:
./todo.txt
./docs/doc1.odt
Solution 5 - Python
The pathlib library is really great for working with files. You can do a recursive glob on a Path object like so.
from pathlib import Path
for elem in Path('/path/to/my/files').rglob('*.*'):
print(elem)
Solution 6 - Python
import glob
import os
root_dir = <root_dir_here>
for filename in glob.iglob(root_dir + '**/**', recursive=True):
if os.path.isfile(filename):
with open(filename,'r') as file:
print(file.read())
**/** is used to get all files recursively including directory.
if os.path.isfile(filename) is used to check if filename variable is file or directory, if it is file then we can read that file.
Here I am printing file.
Solution 7 - Python
If you want a flat list of all paths under a given dir (like find . in the shell):
files = [
os.path.join(parent, name)
for (parent, subdirs, files) in os.walk(YOUR_DIRECTORY)
for name in files + subdirs
]
To only include full paths to files under the base dir, leave out + subdirs.
Solution 8 - Python
I've found the following to be the easiest
from glob import glob
import os
files = [f for f in glob('rootdir/**', recursive=True) if os.path.isfile(f)]
Using glob('some/path/**', recursive=True) gets all files, but also includes directory names. Adding the if os.path.isfile(f) condition filters this list to existing files only
Solution 9 - Python
use os.path.join() to construct your paths - It's neater:
import os
import sys
rootdir = sys.argv[1]
for root, subFolders, files in os.walk(rootdir):
for folder in subFolders:
outfileName = os.path.join(root,folder,"py-outfile.txt")
folderOut = open( outfileName, 'w' )
print "outfileName is " + outfileName
for file in files:
filePath = os.path.join(root,file)
toWrite = open( filePath).read()
print "Writing '" + toWrite + "' to" + filePath
folderOut.write( toWrite )
folderOut.close()
Solution 10 - Python
For my taste os.walk() is a little too complicated and verbose. You can do the accepted answer cleaner by:
all_files = [str(f) for f in pathlib.Path(dir_path).glob("**/*") if f.is_file()]
with open(outfile, 'wb') as fout:
for f in all_files:
with open(f, 'rb') as fin:
fout.write(fin.read())
fout.write(b'\n')
Solution 11 - Python
os.walk does recursive walk by default. For each dir, starting from root it yields a 3-tuple (dirpath, dirnames, filenames)
from os import walk
from os.path import splitext, join
def select_files(root, files):
"""
simple logic here to filter out interesting files
.py files in this example
"""
selected_files = []
for file in files:
#do concatenation here to get full path
full_path = join(root, file)
ext = splitext(file)[1]
if ext == ".py":
selected_files.append(full_path)
return selected_files
def build_recursive_dir_tree(path):
"""
path - where to begin folder scan
"""
selected_files = []
for root, dirs, files in walk(path):
selected_files += select_files(root, files)
return selected_files
Solution 12 - Python
I think the problem is that you're not processing the output of os.walk correctly.
Firstly, change:
filePath = rootdir + '/' + file
to:
filePath = root + '/' + file
rootdir is your fixed starting directory; root is a directory returned by os.walk.
Secondly, you don't need to indent your file processing loop, as it makes no sense to run this for each subdirectory. You'll get root set to each subdirectory. You don't need to process the subdirectories by hand unless you want to do something with the directories themselves.
Solution 13 - Python
Try this:
import os
import sys
for root, subdirs, files in os.walk(path):
for file in os.listdir(root):
filePath = os.path.join(root, file)
if os.path.isdir(filePath):
pass
else:
f = open (filePath, 'r')
# Do Stuff
Solution 14 - Python
If you prefer an (almost) Oneliner:
from pathlib import Path
lookuppath = '.' #use your path
filelist = [str(item) for item in Path(lookuppath).glob("**/*") if Path(item).is_file()]
In this case you will get a list with just the paths of all files located recursively under lookuppath. Without str() you will get PosixPath() added to each path.
Solution 15 - Python
If just the file names are not enough, it's easy to implement a Depth-first search on top of os.scandir():
stack = ['.']
files = []
total_size = 0
while stack:
dirname = stack.pop()
with os.scandir(dirname) as it:
for e in it:
if e.is_dir():
stack.append(e.path)
else:
size = e.stat().st_size
files.append((e.path, size))
total_size += size
The docs have this to say:
> The scandir() function returns directory entries along with file attribute information, giving better performance for many common use cases.
Solution 16 - Python
This worked for me:
import glob
root_dir = "C:\\Users\\Scott\\" # Don't forget trailing (last) slashes
for filename in glob.iglob(root_dir + '**/*.jpg', recursive=True):
print(filename)
# do stuff