第一讲：基础数据类型

# -*- coding:UTF-8 -*-
# 变量
s = 'Hello World'
print(s)
print(s[5:])
print(s[:4])
# s[2:]
# print
# s * 2
# print
# s + " TEST"
#
# # 列表 //可变的数据结构
# list_a = ["str", 1, ["a", "b", "c"], 4]
# list_b = ["hello"]
#
# print
# list_a
# list_a = ["str", 1, ["a", "b", "c"], 3] # 可变的数据结构
# print
# list_a
# print
# list_a[1:3]
# print
# list_a[1:]
# print
# list_b * 2
# print
# list_a + list_b
#
# # 元组 //不可变的数据结构(类似 string 赋值操作产生新空间
# tuple_a = ("str", 1, ["a", "b", "c"], 4)
# tuple_b = ("hello",)
#
# print
# tuple_a
# tuple_a = ("str", 1, ["a", "b", "c"], "123")
# print
# tuple_a
# tuple_a = (1, "str", ["a", "b", "c"])
# print
# tuple_a
# print
# tuple_a[1:3]
# print
# print(tuple_a[:])
# tuple_b * 2
# print
# tuple_a + tuple_b
# 字典 类似于map<a,b>.
dict_a = {
"name": "Alan",
"age": 24,
1: "level_1"
}
print("nownownownownownowo")
print(dict_a["name"])
print(dict_a["age"])
print(dict_a[1])
print("name" in dict_a) # name是否存在key中
print("xxx" in dict_a) # -----------------
print(dict_a.keys()) # 返回所有的索引
print(dict_a.values()) # 返回所有的值
print(dict_a.items()) # 返回所有的（无序）