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I have several files and want to add some text to them (files are named as changed_1, changed_2, changed_3 and so on) in python. Here I copied a piece of my file:

$MeshFormat
2.2 0 8
3 1 "volume_1"
$EndPhysicalNames

I want to add line/s exactly after the 3rd line (3 1 "volume_1"). I have another variable named as n_iteration. If n_iteration is 2, I want to add 3 2 "volume_2" exactly after the 3rd line. If it is 3, I want to add 3 2 "volume_2" and 3 3 "volume_3" and so on. Finally I want to have my files changed and saved exactly like the input format but with these added lines (let's say n_iteration = 4):

$MeshFormat
2.2 0 8
3 1 "volume_1"
3 2 "volume_2"
3 3 "volume_3"
3 4 "volume_4"
$EndPhysicalNames

Point is that I want to do the same (adding these lines) for several files. I tried the following code but I was not successful. Firstly, it is doing the iteration over n_iteration rather than my files (it is making 4 outputs rather than i ones). I have three inputs but it is making four outputs which all are resulted from the last file (last i from the first for loop). It has also a problem for doing what I want (it adds new line differently in outputs):

from glob import glob
all_files = glob('changed_*')
for i in all_files:
    with open(i, "r") as f:
        data = f.readlines()
        n_iteration = 4
        for j in range(n_iteration,0,-1):
            with open('new'+ str (j), "w") as f:
                data.insert(2, ('3 ' + str(j) +' "volume_' + str(j) + '"\n'))
                del data[2+n_iteration]
                for c in data:
                    f.write(c)

In advance, I do appreciate any help.

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  • can you show us what the file looks like after the script runs Commented Nov 3, 2020 at 14:44
  • dear @Avi Baruch, files are .msh files and only contain simple text. But they have thousands of rows. I only showed here first four lines. Commented Nov 3, 2020 at 14:48
  • thats fine, just show the affected lines after so I can see what wrong Commented Nov 3, 2020 at 14:51
  • I did it for three files and wanted to add four lines (n_iteration = 4). It gave me four files, which are all exported from the last file imported to algorithm in the first for loop. the first file is completely OK. Second one= $MeshFormat 2.2 0 8 3 2 "volume_2" 3 3 "volume_3" 3 4 "volume_4" 3 1 "volume_1". Third one= $MeshFormat 2.2 0 8 3 3 "volume_3" 3 4 "volume_4" 3 1 "volume_1". Fourth one = $MeshFormat 2.2 0 8 3 4 "volume_4" 3 1 "volume_1". So, I have four outputs rather than three ones and also they are wrong. Commented Nov 3, 2020 at 14:57

1 Answer 1

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1

Ok so a wide aproximation to your needs could be:

import re
from pathlib import Path


regex = re.compile(r'\d\s\d\s\"volume_\d\"') # X X "volume_N"

def process_files(folder_path, n_iteration):
    txt_folder = Path(folder_path).rglob('*.txt')
    files = [x for x in txt_folder]

    for file_name in files:
        with open(file_name, 'r') as f:
            new_content = []
            current_iteration = n_iteration
            lines = f.readlines()
            for text_line in lines:
                if regex.match(text_line):
                    new_content.extend(new_volume_lines(current_iteration))
                    current_iteration += 1
                else:
                    new_content.append(text_line)
            f.close()

        with open(file_name, 'w') as f:
            for new_line in new_content:
                f.write(new_line)
            f.close()


def new_volume_lines(current_iteration):
    return [
        '3 {0} \"volume_{0}\"\n'.format(i + 1) for i in range(current_iteration)
    ]

Run example, let's say we have a txt at "./path/to/folder"

$MeshFormat
2.2 0 8
3 1 "volume_1"
$EndPhysicalNames

If we run:

process_files('./path/to/folder', 3)

the file will end up like this:

$MeshFormat
2.2 0 8
3 1 "volume_1"
3 2 "volume_2"
3 3 "volume_3"
$EndPhysicalNames
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3 Comments

Dear @Manu, I do appreciate you for giving time to my problem. I have a question. What should I write in front of the last for? It should be the last for condition in my first code?
ok, I'm updating the answer to a complete-working solution
Thank you, I appreciate your help.

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