python之序列解包

python之序列解包

可以使用序列解包功能对多个变量同时进行赋值。

x , y ,z = 1,2,3
print("x , y ,z = 1,2,3 :",x,y,z)
v_tuple = (False,3.5,'exp')
(x , y ,z) = v_tuple
print("v_tuple = (False,3.5,'exp'):",x , y ,z)
x , y ,z =v_tuple
print("v_tuple = (False,3.5,'exp')\n x , y ,z =v_tuple:",x , y ,z)
print(x,y)
x , y = y ,x
print(x,y)
x , y ,z = range(1,4)
print(x , y ,z)
x , y ,z = iter([1,5,9])
print(x , y ,z)
x , y ,z = map(float,range(3))
print(x , y ,z)
a,b,c = "ABC"
print(a,b,c)
keys =['a','b','c']
values =[1,2,3]
for k, v in zip(keys,values):
    print(k,v)

结果：

使用序列解包可以很方便地同时遍历多个序列

 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

对内置函数enumerate()返回的迭代对象进行遍历

 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

使用序列解包遍历字典元素：

>>> 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