Read and write CSV, JSON and YAML

import csv
 
with open("new_users.csv", newline="", encoding="utf-8") as f:
    for row in csv.DictReader(f):
        print(row["username"], row["department"])
 
rows = [{"host": "web1", "status": "ok"}, {"host": "db1", "status": "down"}]
with open("report.csv", "w", newline="", encoding="utf-8") as f:
    writer = csv.DictWriter(f, fieldnames=["host", "status"])
    writer.writeheader()
    writer.writerows(rows)

import json
import subprocess
 
out = subprocess.run(["kubectl", "get", "pods", "-A", "-o", "json"], capture_output=True, text=True, check=True).stdout
data = json.loads(out)
for pod in data["items"]:
    ns = pod["metadata"]["namespace"]
    name = pod["metadata"]["name"]
    phase = pod["status"]["phase"]
    if phase != "Running":
        print(f"{ns}/{name}: {phase}")
 
with open("summary.json", "w", encoding="utf-8") as f:
    json.dump({"checked": len(data["items"])}, f, indent=2)

import yaml
 
with open("deployment.yaml", encoding="utf-8") as f:
    docs = list(yaml.safe_load_all(f))
 
for d in docs:
    if d and d.get("kind") == "Deployment":
        d["spec"]["replicas"] = 3
        for c in d["spec"]["template"]["spec"]["containers"]:
            c.setdefault("resources", {"limits": {"memory": "512Mi"}})
 
with open("deployment.out.yaml", "w", encoding="utf-8") as f:
    yaml.safe_dump_all(docs, f, sort_keys=False)

import configparser
import tomllib
 
with open("pyproject.toml", "rb") as f:
    print(tomllib.load(f)["project"]["name"])
 
ini = configparser.ConfigParser()
ini.read("/etc/dnf/dnf.conf")
print(ini.get("main", "installonly_limit", fallback="3"))