Python中列表,元组,字典和集合的区别及它们之间的转换

# 列表转集合(去重)
list1 = [6, 7, 7, 8, 8, 9]
set(list1)
# {6, 7, 8, 9}
 
#两个列表转字典
list1 = ['key1','key2','key3']
list2 = ['1','2','3']
dict(zip(list1,list2))
# {'key1': '1', 'key2': '2', 'key3': '3'}
 
#嵌套列表转字典
list3 = [['key1','value1'],['key2','value2'],['key3','value3']]
dict(list3)
# {'key1': 'value1', 'key2': 'value2', 'key3': 'value3'}
 
# 列表、元组转字符串
list2 = ['a', 'a', 'b']
''.join(list2)
# 'aab'
 
tup1 = ('a', 'a', 'b')
''.join(tup1)
# 'aab

# 字典转换为字符串
dic1 = {'a':1,'b':2}
str(dic1)
# "{'a': 1, 'b': 2}"
 
# 字典key和value互转
dic2 = {'a': 1, 'b': 2, 'c': 3}
{value:key for key, value in a_dict.items()}
# {1: 'a', 2: 'b', 3: 'c'}

# 字符串转列表
s = 'aabbcc'
list(s)
# ['a', 'a', 'b', 'b', 'c', 'c']
 
# 字符串转元组
tuple(s)
# ('a', 'a', 'b', 'b', 'c', 'c')
 
# 字符串转集合
set(s)
# {'a', 'b', 'c'}
 
# 字符串转字典
dic2 = eval("{'name':'ljq', 'age':24}")
 
# 切分字符串
a = 'a b c'
a.split(' ')
# ['a', 'b', 'c']

base = {'A':1, 'B':2, 'C':3, 'D':4, 'E':5}
subkey = ['C', 'E']
subdict=dict([(key, base[key]) for key in subkey])
print(subdict)——{'C': 3, 'E': 5}

d1={'user':'root','pwd':'1234'}
d2={'ip':'127.0.0.1','port':8080}
d3=dict(d1, **d2)
print(d3)

d1={'user':'root','pwd':'1234'}
d2={'ip':'127.0.0.1','port':8080}
d3={}
for k,v in d1.items():
    d3[k] = v
for k,v in d2.items():
    d3[k] = v
print(d3)

a=[1,2,3,4,5,6]
b=['a','b','c','d']
print(a+b)
 
a=[1,2,3,4,5,6]
b=['a','b','c','d']
a+=b
print(a)
 
a=[1,2,3,4,5,6]
b=['a','b','c','d']
a.extend(b)
print(a)
 
a=[1,2,3,4,5,6]
b=['a','b','c','d']
a[0:0]=b
print(a)
 
li = ['a','b','c']
res1=';'.join(li)
res2=''.join(res1).split(';')