python字典推导式、列表推导式、集合推导式、匿名函数

列表转字典：

list = ["a","b","c","d","e"]
dict1 = {
    
    }
for index in range(len(list)):
    dict1[index] = list[index]
print(dict1)

输出：

{
    
    0: 'a', 1: 'b', 2: 'c', 3: 'd', 4: 'e'}

字典推导式：

list = ["a","b","c","d","e"]
# dict1 = {}
# for index in range(len(list)):
#     dict1[index] = list[index]
# print(dict1)

print({
    
    i:list[i] for i in range(len(list))})

列表推导式：

print([i for i in range(1,101)])

集合推导式：

print({
    
    i for i in range(1,101)})

匿名函数—关键字lambda
匿名函数最常用的是与内置函数结合使用

func2 =lambda x,y: x + y
print(func2(1,3)) 

内置函数：
str() dir() range() len() print() max() min() open() input() int() type() enumerate() list() id() next() iter() tuple() bool() globals() locals() frozenset()

print()函数：

print(help(print))

sep为分隔符，默认为空格，end为结束符，默认换行

print(1,2,4, sep='|', end= '\t')
print(1,2,3)

dict():

# dic = dict(a = 1,b=2)
# print(dic)

dict1 = {
    
    "a":1, "b":2}
print(dict1)

print(abs(-1))

print(sum([12,34,4,5], 10 ))

print(min([22,44,55.1,2]))

list1 = [("a",34 ),("b",32),("c",24)]

def func(x):
    return x[1]

print(min(list1, key=func))

#输出
#1
#65
#2
#('c', 24)

将成绩最低的从属于的那个列表中返回
将成绩最低的分数返回

dic2 = {
    
    'a':['李业',67],'b':['技术',95],'c':['方法',85]}
list = []
for value in dic2.values():
    list.append(value)
    
def func(x):
    return x[1]

print(min(list, key=func))

print(min(list, key=func)[1])

#a = min(list, key=func)
#print(a[1])

#输出
#['李业', 67]
#67

dic2 = {
    
    'a':['李业',67],'b':['技术',95],'c':['方法',85]}

print(dic2[min(dic2, key =lambda x:dic2[x][1])])

print(dic2[min(dic2, key =lambda x:dic2[x][1])][1])

编码解码

#编码
s = '李根'
print(bytes(s, encoding='utf-8'))

#解码
s1 = b'\xe6\x9d\x8e\xe6\xa0\xb9'
print(s1.decode('utf-8'))