python_元组基础

元组的基本特性

>>> a=()

>>> type(a)
<class 'tuple'>
>>> x,y=1,2
>>> a=(x,y)
>>> a
(1, 2)
>>> a=((1,2),(3,4))
>>> a[0][1]
2
>>> a[0]
(1, 2)
>>> a=(1,2)
>>> id(a)
2620703124296
>>> id(a+(1,))
2620703046176
>>> (1,2)*3
(1, 2, 1, 2, 1, 2)

#函数有多个返回值时，以元组的形式返回
>>> def fun():
...     return 1,2
...
>>> fun()
(1, 2)

#tuple(iterable)
>>> tuple([1,3])
(1, 3)
>>> tuple('abc')
('a', 'b', 'c')
>>> tuple({1:2,3:4,5:6})#取字典的key生成的元组
(1, 3, 5)

>>> a=(1,2,3,4)
>>> a=(1,(2,3),[4,5,6],{7:8,9:0})
>>> a[2][0]=14
>>> a
(1, (2, 3), [14, 5, 6], {7: 8, 9: 0})
>>> a[3][7]=18
>>> a
(1, (2, 3), [14, 5, 6], {7: 18, 9: 0})

>>> a[0]=1
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: 'tuple' object does not support item assignment