Common Configuration File Formats and Their Python Parsing Methods

During development, fixed parameters are often stored in a dedicated configuration file to keep core code clean; while a simple .py file works within a single Python project, cross‑language projects benefit from universal formats such as INI, JSON, TOML, and YAML.

INI files consist of sections, keys, and values. Python’s built‑in configparser can read them directly. Example:

[localdb]
host     = 127.0.0.1
user     = root
password = 123456
port     = 3306
database = mysql

Parsing with configparser :

from configparser import ConfigParser
cfg = ConfigParser()
cfg.read("/Users/Bobot/db.ini")
print(cfg.items("localdb"))

JSON is a widely used data‑exchange format that can also serve as a configuration file. Python’s json module provides load() and loads() for reading JSON data.

{
    "localdb": {
        "host": "127.0.0.1",
        "user": "root",
        "password": "123456",
        "port": 3306,
        "database": "mysql"
    }
}

Reading the file:

import json
from pprint import pprint
with open('/Users/Bobot/db.json') as j:
    cfg = json.load(j)['localdb']
    pprint(cfg)

TOML was created by Tom Preston‑Werner and offers a richer syntax than INI while remaining easy to read. Install the third‑party toml package via pip install toml . Example configuration:

[mysql]
host = "127.0.0.1"
user = "root"
port = 3306
database = "test"

[mysql.parameters]
pool_size = 5
charset = "utf8"

[mysql.fields]
pandas_cols = ["id", "name", "age", "date"]

Parsing with toml :

import toml, os, pprint
cfg = toml.load(os.path.expanduser("~/Desktop/config.toml"))
pprint(cfg)

YAML is a highly expressive format popular in DevOps (e.g., Docker Compose). Install pyyaml via pip install pyyaml . Because yaml.load() can execute arbitrary code, use yaml.safe_load() for security.

# Dangerous example (do NOT run)
!!python/object/apply:os.system ["rm -rf /"]

Reading a YAML file safely:

import yaml, os, pprint
with open(os.path.expanduser("~/config.yaml"), "r") as f:
    cfg = yaml.safe_load(f)
    pprint(cfg)

In summary, the complexity of these formats increases roughly as INI < JSON ≈ TOML < YAML; each has its own trade‑offs, and the choice should depend on project requirements, team preferences, and security considerations.