Tuple

Tuple

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什么是Tuple?

• Tuple是python对象组成的序列，此序列内容不可变，即不能编辑元素，这一点和List不同；
• 定义Tuple使用逗号将对象分割，或者将分割的对象放在括号内；

tup1 = ("physics", "chemistry", 1997, 2000)
tup2 = (1, 2, 3, 4, 5, 6, 7)
tup3 = "a", "b", "c", "d"# print result ('a','b','c','d')

• 空tuple

tup1 = () 
print(type(tup1)) # print <class 'tuple'>
print(tup1) #print ()

• 单值tuple

# 注意需要在元素后面加逗号，
tup1 = (50,)

• 与索引一样，tuple索引从0开始，可以切断，级联等

如何获取Tuple的值？

• 可以通过索引的方式获取Tuple内的值

tup1 = ('physics', 'chemistry', 1997, 2000)
tup2 = (1, 2, 3, 4, 5, 6, 7 )
print("tup1[0]: ", tup1[0]) # print tup1[0]: physics
# print 第2到5个数据
print("tup2[1:5]: ", tup2[1:5]) # print tup2[1:5]: (2,3,4,5)

更新Tuple

• Tuple是不可变的，意味着tuple内对象的值不能更新或修改，但是可以通过获取tuple部分对象创建新的tuple

tup1 = (12, 34.56);
tup2 = ('abc', 'xyz');

# Following action is not valid for tuples
# tup1[0] = 100;

# So let's create a new tuple as follows
tup3 = tup1 + tup2;
print(tup3)

• 执行后的结果

(12, 34.56, 'abc', 'xyz')

删除Tuple元素

• 删除tuple单个元素是不可能的，只能用del语句删除整个tuple

tup = ('physics', 'chemistry', 1997, 2000);
print(tup)
del tup
print "After deleting tup : ";
print(tup)

• 执行结果会显示

NameError: name 'tup' is not defined

Tuple的基本操作符

• 与字符串类似，tuple响应+，*的操作符，表示结合，重复；不同的是结果是新的tuple
• 事实上，tuple响应以下所有的操作

Python Expression	Result	Description
len((1,2,3))	3	length
(1, 2, 3) + (4, 5, 6)	(1, 2, 3, 4, 5, 6)	Concatenation
(‘Hi!’,) * 4	(‘Hi!’, ‘Hi!’, ‘Hi!’, ‘Hi!’)	Repetition
3 in (1, 2, 3)	True	Membership
for x in (1, 2, 3): print x	1 2 3	Iteration

索引切片矩阵

• 因为tuple是序列，因此适用于string的索引，切片，矩阵一样适用于tuple

L = ('spam', 'Spam', 'SPAM!')

Python Expression	Result	Description
L[2]	‘SPAM!’	Offsets start at zero
L[-2]	‘Spam’	Negative: count from the right
L[1:]	(‘Spam’, ‘SPAM!’)	Slicing fetches sections

无封闭分隔符

• 任何一组以逗号分隔的的多个对象，写入时不带标识符号，即List不带[],tuple不带(),都默认为tuple

print('abc', -4.24e93, 18+6.6j, 'xyz')
x, y = 1, 2
print("Value of x , y : ", x,y)

• 执行结果

abc -4.24e+93 (18+6.6j) xyz
Value of x , y : 1 2

Tuple的内联方法

Sr.No.	Function with Description
1	cmp(tuple1, tuple2) Compares elements of both tuples.
2	len(tuple) Gives the total length of the tuple
3	max(tuple) Returns item from the tuple with max value.
4	min(tuple) Returns item from the tuple with min value.
5	tuple(seq) Converts a list into tuple.