2020年4月4日python学习笔记——基本数据类型转换

# 本篇总结了一下字符串，列表，字典，元组的连接组合使用和类型的互相转换
# 1.连接两个字符串
# a = "hello "
# b = "word"
# print(a+b)

# 字典的连接
# dict1 = {1: "a", 2: "b"}
# dict2 = {3: "c", 4: "d"}
# dict1.update(dict2)
# print(dict1)

# 列表的连接
# list1 = [1, 2, 3,4]
# list2 = [4, 5, 6]
# list1.extend(list2)#[1, 2, 3, 4, 4, 5, 6]
# print(list1)

# 元组的连接
# tuple1 = (1, 2)
# tuple2 = (3, 4)
# tuple3 = tuple2+tuple1
# print(tuple3)  # (1, 2, 3, 4)

#字典转换为其他类型   字符  列表   元组
# 字典转换为字符串
# dict1 = {1: "a", 2: "b"}
# str1 = str(dict1)
# print(str1)
# print(type(str1))

# 字典转换为列表
# dict1 = {1: "a", 2: "b"}
# list1 = list(dict1.keys())
# list2 = list(dict1.values())
# list3 = list(dict1)#--------------直接返回key值
# print(list1)  # [1, 2]
# print(list2)  # ['a', 'b']
# print(list3)  # [1,2]

# 直接拿到key值
# dict = {"he":"good","live":3}
# print(list(dict))

# 字典转换为元组     原理：等同与字典转换为列表
# dict1 = {1: "a", 2: "b"}
# tuple1 = tuple(dict1.keys())
# tuple2 = tuple(dict1.values())
# tuple3 = tuple(dict1)
# print(tuple1)  # (1, 2)
# print(tuple2)  # ('a', 'b')
# print(tuple3)  # (1, 2)


#列表转换为其他类型    字符串  字典   元组

#列表转换为字符串
# list1 = [1, 2, 3]
# str1 = str(list1)
# print(str1)  # [1, 2, 3]
# print(type(str1))  # <class 'str'>


# 列表转换为字典
# 1.   2个列表，第一个列表作为key    第二个列表作为vule。 使用dict(zip(列表1，列表2))
# list1 = [1, 2, 3]
# list2 = ["a", "b", "c"]
# dict1 = dict(zip(list1, list2))
# print(dict1)  # {1: 'a', 2: 'b', 3: 'c'}

# 2.
# list1 = [1, 2, 3]
# list2 = ["a", "b", "c"]
# dict1 = {}
# for i in list1:
#     dict1[i] = list2[list1.index(i)]
# print(dict1)  # {1: 'a', 2: 'b', 3: 'c'}

# 3   现成的列表对，直接转换成字典模式.
# list1 = [[1, 'a'], [2, 'b'], [3, 'c']]
# dict1 = dict(list1)
# print(dict1)  # {1: 'a', 2: 'b', 3: 'c'}

# # 列表转换为元组
# list1 = [1, 2, 3]
# tuple1 = tuple(list1)
# print(tuple1)  # (1, 2, 3)

#列表转换为其他类型    字符串  字典   列表
# 元组转换为字符串
# tuple1 = (1, 2, 3)
# str1 = str(tuple1)
# print(str1)  # (1, 2, 3)
# print(type(str1))  # <class 'tuple'>


# 元组转换为字典
# 1. 2个元组，第一个元组作为key    第二个元组作为vule。 使用dict(zip(元组1，元组2))
# tuple1 = (1, 2, 3)
# tuple2 = (4, 5, 6)
# dict1 = dict(zip(tuple1, tuple2))
# print(dict1)  # {1: 4, 2: 5, 3: 6}

# 2
# tuple1 = (1, 2, 3)
# tuple2 = (4, 5, 6)
# dict1 = {}
# for i in tuple1:
#     dict1[i] = tuple2[tuple1.index(i)]
# print(dict1)  # {1: 4, 2: 5, 3: 6}

# 3 现成的元组对，直接转换成字典模式.
# tuple1 = (1, 2)
# tuple2 = (4, 5)
# tuple3 = (tuple1, tuple2)
# dict1 = dict(tuple3)
# print(dict1)  # {1: 2, 4: 5}


# 元组转换为列表
# tuple1 = (1, 2)
# list1 = list(tuple1)
# print(list1)  # [1, 2]