Convertir un fichier texte en fichier CSV

#!/usr/bin/env python3
# -*- coding: utf-8 -*-

import io

# Si tu utilises un fichier, tu peux supprimer cette déclaration
data = io.StringIO("""
Websites

Website name: xxxxxxx
Website URL: [https://xxxxxxxx.com]
Login name: xxxxxxx
Login: ***@***
Password: 123456
Comment:

---

Website name:xxxxxxx
Website URL: [http://xxxxxx.com]
Login name: xxxxxxx
Login: xxxxxxx
Password: 123456
Comment:

---

Website name: xxxxxxx
Website URL: [http://xxxxxx.com]
Login name: xxxxxxx
Login: xxxxxxx
Password: 123456
Comment:

---
""")

def parse_txt(data):
    entries = list()
    entry = dict()
    for line in data.readlines():
        line = line.strip()
        if line == "---":
            entries.append(entry)
            entry = dict()
        if ":" in line:
            tab = line.split(":")
            key = tab[0].strip()
            value = ":".join(tab[1:]).strip()
            entry[key] = value
    if entry:
        entries.append(entry)
    return entries

def entries_to_csv(entries, f):
    columns = sorted(set.union(*[
        set(entry.keys())
        for entry in entries
    ]))
    print("#" + ",".join(columns), file=f)
    print(
        "\n".join(
            ",".join(
                entry.get(key, "")
                for key in columns
            )
            for entry in entries
        ),
        file=f
    )

entries = parse_txt(data)

# Avec un fichier:
# filename_txt = "fichier.txt"
# with open(filename_txt) as f_in:
#    entries = parse_txt(f_in)

filename_csv = "fichier.csv"
with open(filename_csv, "w") as f_out:
    entries_to_csv(entries, f_out)

fichier.csv

#Comment,Login,Login name,Password,Website URL,Website name
,***@***,xxxxxxx,123456,https://xxxxxxxx.com,xxxxxxx
,xxxxxxx,xxxxxxx,123456,http://xxxxxx.com,xxxxxxx
,xxxxxxx,xxxxxxx,123456,http://xxxxxx.com,xxxxxxx