python--常用内置库

时间模块：处理日期时间

# 时间模块：处理日期时间
def dateTimeMain():
    from datetime import datetime
    now = datetime.now()
    print(now.strftime("%Y-%m-%d %H:%M:%S"))  # 格式化输出: 2024-07-20 14:30:00
    print("------------------")
dateTimeMain()

os模块：操作系统交互

# os模块：操作系统交互
def osMain():
    import os
    print(os.getcwd())  # 获取当前工作目录
    print("------------------")
    os.mkdir("new_folder")  # 创建文件夹
osMain()

json模块：JSON数据处理

# json模块：JSON数据处理
def jsonMain():
    import json
    data = {"name": "Alice", "age": 25}#键值对对象
    print("---------------")
    print(data["age"])
    json_str = json.dumps(data)  # 转为JSON字符串(转换成字符串)
    print("---------------")
    print(json_str)#打印字符串
    loaded_data = json.loads(json_str)  # 解析JSON（将字符串转化成json对象）
    print("---------------")
    print(loaded_data["name"])
jsonMain()

文件与数据处理进阶

# 文件与数据处理进阶
def openJsonFileMain():
    import json

    data = {"name": "喜羊羊", "age": 25,"sex":"男"}#键值对对象
    # 写入JSON文件
    with open("data.json", "w",encoding="utf-8") as f:
        json.dump(data, f)

    # 读取JSON文件
    with open("data.json", "r",encoding="utf-8") as f:
        dataRead = json.load(f)
        print("--------")
        print(dataRead["name"])
        print(dataRead["age"])

    import csv
    # 读取CSV并转为字典列表
    with open("data.csv", "r",encoding="utf-8") as f:
        reader = csv.DictReader(f)
        print("--------")
        for row in reader:
            print(row["Name"], row["Age"])    
openJsonFileMain()

异常处理

# 异常处理
def exMain():
    class NegativeNumberError(Exception):
        pass

    def check_positive(num):
        if num < 0:
            raise NegativeNumberError("数字不能为负数")
        print(num)

    try:
        check_positive(-10)
    except NegativeNumberError as e:
        print(e)  # 输出: 数字不能为负数
exMain()