【Rollo的Python之路】Python 元组的学习

TUPLE

Python 的元组与列表类似，不同之处在于元组的元素不能修改。

元组使用小括号，列表使用方括号。

元组创建很简单，只需要在括号中添加元素，并使用逗号隔开即可。

tup1 = ("baidu","google","apple","amazon","IBM")

tup2 = (1,2,3,4,5)

tup3 = "a","b","c","d","e" #这样也可以创建一个元组

创建空元组

tup4 = ()

元组中只包含一个元素时，需要在元素后面添加逗号，否则括号会被当作运算符使用：

tup1 = (99)
print(type(tup1))

tup2 = (101,)
print(type(tup2))

#执行结果：

<class 'int'>
<class 'tuple'>

访问元组

元组可以使用下标索引来访问元组中的值，如下实例

tup1 = ("baidu","google","apple","amazon","IBM")

tup2 = (1,2,3,4,5)

tup3 = "a","b","c","d","e",'f'

print(tup1[0])
print(tup2[1],tup2[4])
print(tup3[0],tup3[2],tup3[5])
print(tup2[0:3])

#执行结果：

baidu
2 5
a c f
(1, 2, 3)

修改元组

元组中的元素值是不允许修改的，但我们可以对元组进行连接组合，如下实例:

tup1 = ("baidu","google","apple","amazon","IBM")

tup2 = (1,2,3,4,5)

tup3 = "a","b","c","d","e",'f'

tup4 = tup1 + tup2
print(tup4)

#执行结果：

('baidu', 'google', 'apple', 'amazon', 'IBM', 1, 2, 3, 4, 5) #相当于列表的extend方法

删除元组

元组中的元素值是不允许删除的，但我们可以使用del语句来删除整个元组，如下实例:

tup1 = ("baidu","google","apple","amazon","IBM")

tup2 = (1,2,3,4,5)

tup3 = "a","b","c","d","e",'f'

del tup1  #删除整个元组，但是不是能删除元组的元素，不然就修改了元组，因为：元组是不能修心的！！！！

元组运算符

与字符串一样，元组之间可以使用 + 号和 * 号进行运算。这就意味着他们可以组合和复制，运算后会生成一个新的元组。

1.0 “+” 元组可以相加，组成一个新的元组

tup1 = ("baidu","google","apple","amazon","IBM")

tup2 = (1,2,3,4,5)

tup3 = "a","b","c","d","e",'f'

tup4 = tup1 + tup2 + tup3
print(tup4)

#执行结果：

('baidu', 'google', 'apple', 'amazon', 'IBM', 1, 2, 3, 4, 5, 'a', 'b', 'c', 'd', 'e', 'f')

2.0 元组可以复制，用*

tup1 = ("baidu","google","apple","amazon","IBM")

tup2 = (1,2,3,4,5)

tup3 = "a","b","c","d","e",'f'

print((tup1)*2) #2个tup1
print((tup2)*3) #3个tup2
print((tup3)*4) #4个tup3

#执行结果：

('baidu', 'google', 'apple', 'amazon', 'IBM', 'baidu', 'google', 'apple', 'amazon', 'IBM')
(1, 2, 3, 4, 5, 1, 2, 3, 4, 5, 1, 2, 3, 4, 5)
('a', 'b', 'c', 'd', 'e', 'f', 'a', 'b', 'c', 'd', 'e', 'f', 'a', 'b', 'c', 'd', 'e', 'f', 'a', 'b', 'c', 'd', 'e', 'f')

3.0 查询元组的元素的个数：

tup1 = ("baidu","google","apple","amazon","IBM")

tup2 = (1,2,3,4,5)

tup3 = "a","b","c","d","e",'f'

print(len(tup1))
print(len(tup2))
print(len(tup3))

#执行结果：

5
5
6

4.0 IN 判断是否在元组里面：

"baidu" in tup1  #True

5.0 for 迭代

tup1 = ("baidu","google","apple","amazon","IBM")

tup2 = (1,2,3,4,5)

tup3 = "a","b","c","d","e",'f'

for i in tup1:
    print(i)
for i in tup2:
    print(i)
for i in tup3:
    print(i)

#执行结果：
baidu
google
apple
amazon
IBM
1
2
3
4
5
a
b
c
d
e
f

6.0 tuple 的切片方法：

tup1 = ("baidu","google","apple","amazon","IBM")

tup2 = (1,2,3,4,5)

tup3 = "a","b","c","d","e",'f'

print(tup1[1]),
print(tup2[-1]),
print(tup3[4:1:-1])

#执行结果：
google
5
('e', 'd', 'c')

元组内置函数

Python元组包含了以下内置函数

1.0 len(tuple)：计算元组元素个数。

tup1 = ("baidu","google","apple","amazon","IBM")

tup2 = (1,2,3,4,5)

tup3 = "a","b","c","d","e",'f'

print(len(tup1))
print(len(tup2))
print(len(tup3))

#执行结果：

5
5
6

2.0 max(tuple) :返回元组中元素最大值。

tup1 = ("baidu","google","apple","amazon","IBM")

tup2 = (1,2,3,4,5)

tup3 = "a","b","c","d","e",'f'

print(max(tup1)),#ASCII 最大值
print(max(tup2)),
print(max(tup3))

#执行结果：

google
5
f

3.0 min(tuple):返回元组中元素最小值。

tup1 = ("baidu","google","apple","amazon","IBM")

tup2 = (1,2,3,4,5)

tup3 = "a","b","c","d","e",'f'

print(min(tup1)),#ASCII 最小值
print(min(tup2)),
print(min(tup3))

#执行结果：

IBM
1
a

4.0 tuple(seq):将列表转换为元组。

list1 = ["baidu","google","apple","amazon","IBM"]

tup1 = tuple(list1)

print(tup1)

#执行结果：

('baidu', 'google', 'apple', 'amazon', 'IBM')

5.0 list(tuple):将元组转为列表。

tup3 = ("a","b","c","d","e",'f')
list1 = list(tup3)
print(list1)

#执行结果：

['a', 'b', 'c', 'd', 'e', 'f']