python 序列解包的多种形式及用法解析

>>> x, y, z = 1, 2, 3 #多个变量同时赋值
>>> v_tuple = (False, 3.5, 'exp')
>>> (x, y, z) = v_tuple
>>> x, y, z = v_tuple
>>> x, y, z = range(3)#可以对range对象进行序列解包
>>> x, y, z = map(str, range(3)) #使用迭代对象进行序列解包

>>> a = [1, 2, 3]
>>> b, c, d = a #列表也支持序列解包的用法
>>> x, y, z = sorted([1, 3, 2])  #sorted()函数返回排序后的列表
>>> s = {'a':1, 'b':2, 'c':3}
>>> b, c, d = s.items()
>>> b
('c', 3)
>>> b, c, d = s #使用字典时不用太多考虑元素的顺序
>>> b
'c'
>>> b, c, d = s.values()
>>> print(b, c, d)
1 3 2

>>> keys = ['a', 'b', 'c', 'd']
>>> values = [1, 2, 3, 4]
>>> for k, v in zip(keys, values):
print(k, v)
a 1
b 2
c 3
d 4

>>> x = ['a', 'b', 'c']
>>> for i, v in enumerate(x):
print('The value on position {0} is {1}'.format(i,v))
The value on position 0 is a
The value on position 1 is b
The value on position 2 is c

>>> s = {'a':1, 'b':2, 'c':3}
>>> for k, v in s.items():  #字典中每个元素包含“键”和“值”两部分
print(k, v)
a 1
c 3
b 2

>>> print(*[1, 2, 3], 4, *(5, 6))
1 2 3 4 5 6
>>> *range(4), 4
(0, 1, 2, 3, 4)
>>> {*range(4), 4, *(5, 6, 7)}
{0, 1, 2, 3, 4, 5, 6, 7}
>>> {'x': 1, **{'y': 2}}
{'y': 2, 'x': 1}

>>> nums = 1, 2, 3
>>> print(nums)
(1, 2, 3)
>>> print(nums[1])
2

>>> tuple_temp = tuple(range(1, 10, 2))
>>> print(tuple_temp)
(1, 3, 5, 7, 9)
>>> a, b, c, d, e = tuple_temp
>>> print(a, b, c, d, e)
1 3 5 7 9

>>> a, b, c = 1, 2, 3
>>> print(a, b, c)
1 2 3

abc = 1, 2, 3

a, b, c = abc

>>> a, b, *restnum = range(10)
>>> print(a)
0
>>> print(b)
1
>>> print(restnum)
[2, 3, 4, 5, 6, 7, 8, 9]

>>> *frontnum, lastnum = range(10)
>>> print(frontnum)
[0, 1, 2, 3, 4, 5, 6, 7, 8]
>>> print(lastnum)
9

>>> frontnum, *middlenum, lastnum = range(10)
>>> print(frontnum)
0
>>> print(middlenum)
[1, 2, 3, 4, 5, 6, 7, 8]
>>> print(lastnum)
9