Python 常用标准库

TIP

Python 标准库覆盖了 JSON、时间、集合、正则等常见需求，无需安装第三方包。

JSON

import json
data = {"name": "张三", "age": 25}
json_str = json.dumps(data, ensure_ascii=False, indent=2)
parsed = json.loads(json_str)

日期时间

from datetime import datetime, timedelta

now = datetime.now()
print(now.strftime("%Y-%m-%d %H:%M:%S"))

date = datetime.strptime("2024-01-01", "%Y-%m-%d")
tomorrow = now + timedelta(days=1)

collections

from collections import defaultdict, Counter

word_count = defaultdict(int)
for word in ["a", "b", "a", "c", "b", "a"]:
    word_count[word] += 1

cnt = Counter("hello world")
print(cnt.most_common(3))

re 正则表达式

import re
pattern = r"\d{3}-\d{4}-\d{4}"
match = re.search(pattern, "电话: 138-1234-5678")
if match:
    print(match.group())