opening and reading all the files in a directory in python - python beginner

• Separate the different functions of the thing you want to do.
• Use generators wherever possible. Especially if there are a lot of files or large files

Imports

from pathlib import Path
import sys

Deciding which files to process:

source_dir = Path('results/')

files = source_dir.iterdir()

[Optional] Filter files

For example, if you only need files with extension .ext

files = source_dir.glob('*.ext')

Process files

def process_files(files):
    for file in files:
        with file.open('r') as file_handle :
            for line in file_handle:
                # do your thing
                yield line

Save the lines you want to keep

def save_lines(lines, output_file=sys.std_out):
    for line in lines:
        output_file.write(line)

you forgot indentation at this line allLines = file.readlines() and maybe you can try that :

import os

allLines = []
path = 'results/'
fileList = os.listdir(path)
for file in fileList:
   file = open(os.path.join('results/'+ i), 'r')
   allLines.append(file.read())
print(allLines)

You forgot to indent this line allLines.append(file.read()). Because it was outside the loop, it only appended the file variable to the list after the for loop was finished. So it only appended the last value of the file variable that remained after the loop. Also, you should not use readlines() in this way. Just use read() instead;

import os

allLines = []
path = 'results/'
fileList = os.listdir(path)
for file in fileList:
   file = open(os.path.join('results/'+ i), 'r')
   allLines.append(file.read())
print(allLines)

This also creates a file containing all the files you wanted to print.

rootdir= your folder, like 'C:\\Users\\you\\folder\\'
import os
f = open('final_file.txt', 'a')
for root, dirs, files in os.walk(rootdir):  
    for filename in files:
        data = open(full_name).read()
            f.write(data + "\n")                 
f.close()

This is a similar case, with more features: Copying selected lines from files in different directories to another file