Need to find out how can i write to a .txt file so that the latest results are appended starting from the beginning of the file

Question

I have build a code that does the following:

#code is supposed to access servers about 20 of them
#server details are in 'CheckFolders.ini'
# retrieve size, file numbers and number of folders information
# put all that in a file CheckFoldersResult.txt

Need to find out how can i write to CheckFoldersResult.txt so that the latest results are appended starting from the beginning of the file instead of appending at end of the existing text.

please provide a [mre] with your attempt to do what you are asking for and what exactly failed — Matiiss, Oct 28 '21 at 16:48
To append to the beginning of a file, you will have to re-write its entire contents. — martineau, Oct 28 '21 at 16:59

score 0 · Answer 1 · answered Oct 28 '21 at 16:50

0

I'd read the results, insert the lines I want at the top, then overwrite the file like so:

def update_file(filepath, new_lines):
    lines = []
    with open(filepath, 'r') as f:
        lines = f.readlines()
    rev_lines = reversed(new_lines)
    for line in rev_lines:
        lines.insert(0, line)
    with open(filepath, 'w') as f:
        f.writelines(lines)

answered Oct 28 '21 at 16:50

dsillman2000

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I don't quite get why this is accumulating *all* lines in-memory first, and using a rather inefficient insert-0 to boot. Why not ``f.writelines(new_lines)`` and then ``f.writelines(lines)`` *without* merging ``new_lines`` and ``lines``? – MisterMiyagi Oct 28 '21 at 16:59

Need to find out how can i write to a .txt file so that the latest results are appended starting from the beginning of the file

1 Answers1