## The function returns multiple values:
1. If the function returns multiple values, it will put the values in a tuple by default
def say():
return 1,2,3,4
print(say()) ------------- (1,2,3,4)
2. The function returns multiple values, which can be received by multiple variables
def say():
return 1,2,3,4
a,b,c,d = say() ------------a=1,b=2,c=3,d=4
print(a,b,c,d)
## Anonymous function (lambda)
function is very simple, only used once
res = lambda x:x+1 #After the colon is the function body, which is also the processing logic of the function, and before the colon is the return value
print(res(1))
Example: dictionary sort
#Dictionary is unordered, you can't sort the dictionary directly, you have to convert it to a list
d = {'a':1,'b':2,'c':3}
res = sorted(d.items(),key = lambda x:x[0])
print(res)
## Define the parameter type
For example: def is_float(s:str): #Specify that the parameter s is a string type, but it does not have any special effect, and other types can still be passed after the definition