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How to run through a list of variables as part of a file path?

I need to go through a series of identical directories and combine two .txt files from each into a single file.
I tried using a list (partial list included, in total ~1000 directories) but Python keeps interpreting my list variable as text in the file path.
import os
for subject in ['100307', '100408', '101107']:
os.chdir("/Users/me/Desktop/SubjPerformance/(subject)")
filenames = ['0bk_nlr.txt', '2bk_nlr.txt']
with open('all_bk_nlr', 'w') as outfile:
for fname in filenames:
with open(fname) as infile:
outfile.write(infile.read())
The error I keep getting is:
FileNotFoundError: [Errno 2] No such file or directory: '/Users/me/Desktop/SubjPerformance/(subject)'
Obviously, (subject) is not part of the file path. I want it to take an item from my list, but it is interpreting what I want to be a list variable as text instead.
I'm sure this could also be done with a wildcard character that runs through every subdirectory within /SubjPerformance but I don't know how to build that loop.
Thanks for your help, and sorry for the ignorant question--I'm a neuroscience researcher, not a developer!

You use incorrect syntax, use
"/Users/me/Desktop/SubjPerformance/%s" % subject
or
"/Users/me/Desktop/SubjPerformance/{}".format(subject)
instead.

In order to use a variable inside a string, you can use "/Users/me/Desktop/SubjPerformance/%s" % subject. You can learn more about string formatting here.

Python Delete Files in Directory from list in Text file

I've searched through many answers on deleting multiple files based on certain parameters (e.g. all txt files). Unfortunately, I haven't seen anything where one has a longish list of files saved to a .txt (or .csv) file and wants to use that list to delete files from the working directory.
I have my current working directory set to where the .txt file is (text file with list of files for deletion, one on each row) as well as the ~4000 .xlsx files. Of the xlsx files, there are ~3000 I want to delete (listed in the .txt file).
This is what I have done so far:
import os
path = "c:\\Users\\SFMe\\Desktop\\DeleteFolder"
os.chdir(path)
list = open('DeleteFiles.txt')
for f in list:
os.remove(f)
This gives me the error:
OSError: [WinError 123] The filename, directory name, or volume label syntax is incorrect: 'Test1.xlsx\n'
I feel like I'm missing something simple. Any help would be greatly appreciated!
Thanks

Strip ending '\n' from each line read from the text file;
Make absolute path by joining path with the file name;
Do not overwrite Python types (i.e., in you case list);
Close the text file or use with open('DeleteFiles.txt') as flist.
EDIT: Actually, upon looking at your code, due to os.chdir(path), second point may not be necessary.
import os
path = "c:\\Users\\SFMe\\Desktop\\DeleteFolder"
os.chdir(path)
flist = open('DeleteFiles.txt')
for f in flist:
fname = f.rstrip() # or depending on situation: f.rstrip('\n')
# or, if you get rid of os.chdir(path) above,
# fname = os.path.join(path, f.rstrip())
if os.path.isfile(fname): # this makes the code more robust
os.remove(fname)
# also, don't forget to close the text file:
flist.close()

As Henry Yik pointed in the commentary, you need to pass the full path when using os.remove function. Also, open function just returns the file object. You need to read the lines from the file. And don't forget to close the file. A solution would be:
import os
path = "c:\\Users\\SFMe\\Desktop\\DeleteFolder"
os.chdir(path)
# added the argument "r" to indicates only reading
list_file = open('DeleteFiles.txt', "r")
# changing variable list to _list to do not shadow
# the built-in function and type list
_list = list_file.read().splitlines()
list_file.close()
for f in _list:
os.remove(os.path.join(path,f))
A further improvement would be use list comprehension instead of a loop and a with block, which "automagically" closes the file for us:
with open('DeleteFiles.txt', "r") as list_file:
_list = list_file.read().splitlines()
[os.remove(os.path.join(path,f)) for f in _list]

How can I modify my script to allow Python to search recursively thought my folder structure?

Hello fellow Pythonistas,
I have a script which searches through all files contained within a single directory for a 'string' keyword. If it finds the 'string' keyword within any of the files, it will print the name of this file to the IDLE command screen. It seems to work quite well. The inputs are gathered by the program using user prompts.Typically I am searching for a single word within a large series of text files.
HOWEVER - Now I want to build on this in two ways
1) I want to modify the code to that it can also search through all the files contained within sub-folders within the specified directory.
2) I would also like to specify that the searches are limited to a certain type of file extension such as .txt.
Can anyone provide some guidance on either of these two enhancements ???
I am using Python 3 and am VERY new to Python (Just started playing with it 2 weeks ago in an attempt to automate some boring searches through my employers folder structures)
Much appreciated to anyone who can provide some help.
Cheers,
Fraz
# This script will search through all files within a single directory for a single key word
# If the script finds the word within any of the files it will print the name of this file to the command line
import os
print ('When answering questions, do not add a space and use forward slash separators on file paths')
print ('')
# Variables to be defined by user input
user_input = input('Paste the directory you want to search?')
directory = os.listdir(user_input)
searchstring = input('What word are you trying to find within these files?')
for fname in directory:
if os.path.isfile(user_input + os.sep + fname):
# Full path
f = open(user_input + os.sep + fname, 'r')
if searchstring in f.read():
print('found string in file "%s"' % fname)
f.close()enter code here

Run only if "if " statement is true.!

So I've a question, Like I'm reading the fits file and then i'm using the information from the header of the fits to define the other files which are related to the original fits file. But for some of the fits file, the other files (blaze_file, bis_file, ccf_table) are not available. And because of that my code gives the pretty obvious error that No Such file or directory.
import pandas as pd
import sys, os
import numpy as np
from glob import glob
from astropy.io import fits
PATH = os.path.join("home", "Desktop", "2d_spectra")
for filename in os.listdir(PATH):
if filename.endswith("_e2ds_A.fits"):
e2ds_hdu = fits.open(filename)
e2ds_header = e2ds_hdu[0].header
date = e2ds_header['DATE-OBS']
date2 = date = date[0:19]
blaze_file = e2ds_header['HIERARCH ESO DRS BLAZE FILE']
bis_file = glob('HARPS.' + date2 + '*_bis_G2_A.fits')
ccf_table = glob('HARPS.' + date2 + '*_ccf_G2_A.tbl')
if not all(file in os.listdir(PATH) for file in [blaze_file,bis_file,ccf_table]):
continue
So what i want to do is like, i want to make my code run only if all the files are available otherwise don't. But the problem is that, i'm defining the other files as variable inside the for loop as i'm using the header information. So how can i define them before the for loop???? and then use something like
So can anyone help me out of this?

The filenames returned by os.listdir() are always relative to the path given there.
In order to be used, they have to be joined with this path.
Example:
PATH = os.path.join("home", "Desktop", "2d_spectra")
for filename in os.listdir(PATH):
if filename.endswith("_e2ds_A.fits"):
filepath = os.path.join(PATH, filename)
e2ds_hdu = fits.open(filepath)
…
Let the filenames be ['a', 'b', 'a_ed2ds_A.fits', 'b_ed2ds_A.fits']. The code now excludes the two first names and then prepends the file path to the remaining two.
a_ed2ds_A.fits becomes /home/Desktop/2d_spectra/a_ed2ds_A.fits and
b_ed2ds_A.fits becomes /home/Desktop/2d_spectra/b_ed2ds_A.fits.
Now they can be accessed from everywhere, not just from the given file path.
I should become accustomed to reading a question in full before trying to answer it.
The problem I mentionned is a problem if you don't start the script from any path outside the said directory. Nevertheless, applying it will make your code much more consistent.
Your real problem, however, lies somewhere else: you examine a file and then, after checking its contents, want to read files whose names depend on informations from that first file.
There are several ways to accomplish your goal:
Just extend your loop with the proper tests.
Pseudo code:
for file in files:
if file.endswith("fits"):
open file
read date from header
create file names depending on date
if all files exist:
proceed
or
for file in files:
if file.endswith("fits"):
open file
read date from header
create file names depending on date
if not all files exist:
continue # actual keyword, no pseudo code!
proceed
Put some functionality into functions (variation of 1.)
Create a loop in a generator function which yields the "interesting information" of one fits file (or alternatively nothing) and have another loop run over them to actually work with the data.
If I am still missing some points or am not detailled enough, please let me know.

Since you have to read the fits file to know the other dependant files names, there's no way you can avoid reading the fit file first. The only thing you can do is test for the dependant files existance before trying to read them and skip the rest of the loop (using continue) if not.

Edit this line
e2ds_hdu = fits.open(filename)
And replace with
e2ds_hdu = fits.open(os.path.join(PATH, filename))

taking data from files which are in folder

How do I get the data from multiple txt files that placed in a specific folder. I started with this could not fix. It gives an error like 'No such file or directory: '.idea' (??)
(Let's say I have an A folder and in that, there are x.txt, y.txt, z.txt and so on. I am trying to get and print the information from all the files x,y,z)
def find_get(folder):
for file in os.listdir(folder):
f = open(file, 'r')
for data in open(file, 'r'):
print data
find_get('filex')
Thanks.

If you just want to print each line:
import glob
import os
def find_get(path):
for f in glob.glob(os.path.join(path,"*.txt")):
with open(os.path.join(path, f)) as data:
for line in data:
print(line)
glob will find only your .txt files in the specified path.
Your error comes from not joining the path to the filename, unless the file was in the same directory you were running the code from python would not be able to find the file without the full path. Another issue is you seem to have a directory .idea which would also give you an error when trying to open it as a file. This also presumes you actually have permissions to read the files in the directory.
If your files were larger I would avoid reading all into memory and/or storing the full content.

First of all make sure you add the folder name to the file name, so you can find the file relative to where the script is executed.
To do so you want to use os.path.join, which as it's name suggests - joins paths. So, using a generator:
def find_get(folder):
for filename in os.listdir(folder):
relative_file_path = os.path.join(folder, filename)
with open(relative_file_path) as f:
# read() gives the entire data from the file
yield f.read()
# this consumes the generator to a list
files_data = list(find_get('filex'))
See what we got in the list that consumed the generator:
print files_data
It may be more convenient to produce tuples which can be used to construct a dict:
def find_get(folder):
for filename in os.listdir(folder):
relative_file_path = os.path.join(folder, filename)
with open(relative_file_path) as f:
# read() gives the entire data from the file
yield (relative_file_path, f.read(), )
# this consumes the generator to a list
files_data = dict(find_get('filex'))
You will now have a mapping from the file's name to it's content.
Also, take a look at the answer by #Padraic Cunningham . He brought up the glob module which is suitable in this case.

The error you're facing is simple: listdir returns filenames, not full pathnames. To turn them into pathnames you can access from your current working directory, you have to join them to the directory path:
for filename in os.listdir(directory):
pathname = os.path.join(directory, filename)
with open(pathname) as f:
# do stuff
So, in your case, there's a file named .idea in the folder directory, but you're trying to open a file named .idea in the current working directory, and there is no such file.
There are at least four other potential problems with your code that you also need to think about and possibly fix after this one:
You don't handle errors. There are many very common reasons you may not be able to open and read a file--it may be a directory, you may not have read access, it may be exclusively locked, it may have been moved since your listdir, etc. And those aren't logic errors in your code or user errors in specifying the wrong directory, they're part of the normal flow of events, so your code should handle them, not just die. Which means you need a try statement.
You don't do anything with the files but print out every line. Basically, this is like running cat folder/* from the shell. Is that what you want? If not, you have to figure out what you want and write the corresponding code.
You open the same file twice in a row, without closing in between. At best this is wasteful, at worst it will mean your code doesn't run on any system where opens are exclusive by default. (Are there such systems? Unless you know the answer to that is "no", you should assume there are.)
You don't close your files. Sure, the garbage collector will get to them eventually--and if you're using CPython and know how it works, you can even prove the maximum number of open file handles that your code can accumulate is fixed and pretty small. But why rely on that? Just use a with statement, or call close.
However, none of those problems are related to your current error. So, while you have to fix them too, don't expect fixing one of them to make the first problem go away.

Full variant:
import os
def find_get(path):
files = {}
for file in os.listdir(path):
if os.path.isfile(os.path.join(path,file)):
with open(os.path.join(path,file), "r") as data:
files[file] = data.read()
return files
print(find_get("filex"))
Output:
{'1.txt': 'dsad', '2.txt': 'fsdfs'}
After the you could generate one file from that content, etc.
Key-thing:
os.listdir return a list of files without full path, so you need to concatenate initial path with fount item to operate.
there could be ideally used dicts :)
os.listdir return files and folders, so you need to check if list item is really file

You should check if the file is actually file and not a folder, since you can't open folders for reading. Also, you can't just open a relative path file, since it is under a folder, so you should get the correct path with os.path.join. Check below:
import os
def find_get(folder):
for file in os.listdir(folder):
if not os.path.isfile(file):
continue # skip other directories
f = open(os.path.join(folder, file), 'r')
for line in f:
print line