from datetime import datetime, timedelta
# 1. 獲取當(dāng)前時間
now = datetime.now()
print(f"當(dāng)前時間: {now}")
# 2. 格式化輸出 (strftime)
print(now.strftime("%Y-%m-%d %H:%M:%S")) # 2023-10-27 14:30:05
# 3. 字符串轉(zhuǎn)時間對象 (strptime)
date_str = "2023-01-01"
dt_obj = datetime.strptime(date_str, "%Y-%m-%d")
# 4. 時間計算 (timedelta)
yesterday = now - timedelta(days=1)
future = now + timedelta(hours=2)

import math
print(math.pi)        # 圓周率 3.14159...
print(math.sqrt(16))  # 開平方 4.0
print(math.ceil(3.1)) # 向上取整 4

import random
print(random.random())       # 0到1之間的浮點數(shù)
print(random.randint(1, 10)) # 1到10之間的隨機整數(shù)（含10）
fruits = ["蘋果", "香蕉", "橙子"]
print(random.choice(fruits)) # 隨機選一個
items = [1, 2, 3, 4, 5]
random.shuffle(items)        # 打亂列表順序

import json
data = {"name": "Jojo", "age": 25, "is_admin": False}
# 1. 編碼：字典 -> JSON 字符串 (dumps)
json_str = json.dumps(data, indent=4) # indent讓輸出更漂亮
# 2. 解碼：JSON 字符串 -> 字典 (loads)
parsed_data = json.loads(json_str)
# 3. 處理文件 (dump/load)
with open("config.json", "w") as f:
    json.dump(data, f) # 直接寫入文件

import sys
# 1. 獲取命令行參數(shù) (常用語腳本傳參)
# 運行命令: python script.py arg1 arg2
print(sys.argv) 
# 2. 退出程序
# sys.exit(0) # 0表示正常退出
# 3. 模塊搜索路徑
# print(sys.path) 
# 4. 查看系統(tǒng)平臺
print(sys.platform) # win32, darwin(Mac), linux

from collections import Counter, defaultdict
# Counter 示例：統(tǒng)計詞頻
text = "apple banana apple orange apple banana"
counts = Counter(text.split())
print(counts) # Counter({'apple': 3, 'banana': 2, 'orange': 1})
print(counts.most_common(1)) # 獲取出現(xiàn)次數(shù)最多的
# defaultdict 示例
d = defaultdict(int) # 默認值為 0
d["count"] += 1      # 不會報錯，直接從0加到1

import re
text = "我的郵箱是 jojo_123@example.com，請聯(lián)系我。"
# 匹配郵箱的簡單正則
pattern = r'[a-zA-Z0-9_]+@[a-zA-Z0-9]+\.[a-zA-Z]+'
# 搜索
match = re.search(pattern, text)
if match:
    print(f"找到郵箱: {match.group()}")
# 替換
clean_text = re.sub(pattern, "[HIDDEN]", text)
print(clean_text)