Python入门3-变量2

发布时间：2019-09-22 07:53:20编辑：auto阅读（2026）

    1.字典（使用花括号定义）
      dairy_section = {}
      dairy_section["breakfast"] = ("break","milk")
      dairy_section["lunch"] = ("noodles","rices","dishes")
      dairy_section["dinner"] = ("porridge","steamed bun")
      读取时可以使用：
      1）print(dairy_section)：显示全部的值
      2）dairy_section.get("breakfast")：读取特定值
      3）从字典中取键
         print_keys = dairy_section.keys()
         print_values = dairy_section.values(）

    2.引用序列的最后一个元素（元组和列表均属于序列）
      元组（列表）名称[-1],依次类推，比如week = ("Sunday","monday","Tuesday")
      可使用print(week[-1])打印出"Tuesday"

    3.将序列分片
      1)将元组分片：例如workday = ("Monday","Tuesday","Wednesday","Thursday","Friday")
      print(workday[0:2]),显示"Monday"，“Tuesday”
      2)将列表分片：例如workday = ["Mondy","Tuesday","Wednesday","Thursday","Friday"]
      print(workday[1:3]),显示"Tuesday","Wednesday"
      3)将字符分片：例如workday = "from Monday to friday"
      print(workday[2:5]),显示"om "
    4.从列表中弹出元素
      today_times = [2,5,3,6]
      A = today_times.pop(0)
      print(A),显示2,且print(today_times)时显示[5,3,6]

    5.计算元组、列表或字典的长度
      len(元组名或列表名或字典名)

    6.处理集合
      alphabet = ['a','b','b','c','d','e','e']
      alph2 = set(alphabet)
      print(alph2)显示{'a','b','c','d','e'}

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