Python中星号的五种用法小结

>>> 2*3
>>> 6
>>> 2**3
>>> 8

def print_genius(*names):
    print(type(names))
    for n in names:
        print(n)

print_genius('Elon Mask', 'Du Fu ', 'Li Bai')
# <class 'tuple'>
# Elon Mask
# Du Fu 
# Li Bai
def top_genius(**names):
    print(type(names))
    for k, v in names.items():
        print(k, v)

top_genius(Top1="Elon Mask", Top2="Du Fu", Top3="Li Bai")
# <class 'dict'>
# Top1 Elon Mask
# Top2 Du Fu
# Top3 Li Bai

def func(*args, **kwargs):
    pass

def genius(*, first_name, last_name):
    print(first_name, last_name)

# genius('Li','Bai')
# TypeError: genius() takes 0 positional arguments but 2 were given
genius(first_name='Li', last_name='Bai')
# Li Bai

def genius(age, *, first_name, last_name):
    print(first_name, last_name, 'is', age)
genius(28, first_name='Li', last_name='Bai')
# Li Bai is 28

A = [1, 2, 3]
B = (4, 5, 6)
C = {7, 8, 9}
L = []
for a in A:
    L.append(a)
for b in B:
    L.append(b)
for c in C:
    L.append(c)
print(L)
# [1, 2, 3, 4, 5, 6, 8, 9, 7]

A = [1, 2, 3]
B = (4, 5, 6)
C = {7, 8, 9}
L = [a for a in A] + [b for b in B] + [c for c in C]
print(L)
# [1, 2, 3, 4, 5, 6, 8, 9, 7]

A = [1, 2, 3]
B = (4, 5, 6)
C = {7, 8, 9}
L = [*A, *B, *C]
print(L)
# [1, 2, 3, 4, 5, 6, 8, 9, 7]

D = {'first': 1, 'second': 2, 'third': 3}

print(*D)
# first second third

# print(**D)
# TypeError: 'first' is an invalid keyWord argument for print()

print('{first},{second},{third}'.fORMat(**D))
# 1,2,3

L = [1, 2, 3, 4, 5, 6, 7, 8]
a, *b = L
print(a)
# 1
print(b)
# [2, 3, 4, 5, 6, 7, 8]