python 列表，元组，字典，集合，字符串相互转换
1. 列表与元组的互换-------------------------------------------------
1.1将列表转化为元组
li = [1, 2, 3]
t = tuple(li)
print(t, type(t))
1.2 将元组转换成列表
del list #先清除list缓存
tu = (1, 2, 3)
li = list(tu)
print(li, type(li))
2. 列表与字符串的互换-----------------------------------------------
2.1列表转换成字符串
li = ['人', '生', '苦', '短']
str1 = ''.join(li)
print(str1, type(str1))
2.2字符串转换成列表
str2 = 'hello python'
li1 = str2.split(' ')
print(li1, type(li1))
3. 列表与字典转换----------------------------------------------------
3.1列表转字典方式一
list1 = ['name', 'age', 'sex']
list2 = ['张三', 18, '男']
dict = {}
for i in range(len(list1)):
dict[list1[i]] = list2[i]
print(dict, type(dict))
3.2列表转字典方式二：使用内置函数zip
del dict#清除缓存
list1 = ['name', 'age', 'sex']
list2 = ['张三', 18, '男']
d = dict(zip(list1, list2))
print(d)
3.3字典转换成列表
dict = {'name': '张三', 'age': 18, 'sex': '男'}
keys = list(dict.keys())
values = list(dict.values())
print(keys, type(keys))
print(values, type(values))
3.4嵌套列表转字典
list3 = [['key1','value1'],['key2','value2'],['key3','value3']]
print(dict(list3))
5.列表与集合转换------------------------------------------------------------
5.1列表转集合
list1 = [1, 3, 4, 3, 2, 1]
s1 = set(list1)
print(s1, type(s1))
输出结果：{1, 2, 3, 4} <class 'set'>
5.2集合转列表
list1 = [1, 3, 4, 3, 2, 1]
s1 = set(list1)
list2 = list(s1.intersection(s1))
print(list2, type(list2))
6.元组和字符串转换--------------------------------------------------------------------
6.1元组转换成字符串和列表方法一样
6.2字符串转换成元组，需要将字符串转换成列表，在利用列表转成元组
list = []
a = '人生苦短'
list.append(a)
print(list)
b = tuple(list)
print(b, type(b))
7.元组和字典转换---------------------------------------------------------------------
7.1字典转元组
dict = {'name': 'xiaoming', 'age': 18}
tup = tuple(dict)
print(tup) # 只转换了key
tup2 = tuple(dict.values())
print(tup2)
7.2元组不能转成字典
8.字典和字符串转换--------------------------------------------------------
8.1字典转换为字符串
dic1 = {'a': 1, 'b': 2}
str1 = str(dic1)
8.2字符串转字典
dic2 = eval("{'name':'xiaoming', 'age':18}")
print(dic2, type(dic2))
9.字符串和集合转换
9.1字符串转集合
str1 = 'hello'
s1 = set(str1)
print(s1, type(s1))
10.字典key和value值转换
dic1 = {'a': 1, 'b': 2, 'c': 3}
dic2 = {value: key for key, value in dic1.items()}
print(dic2)
