元组

元组的实例：

 

tup1 = ('physics', 'chemistry', 1997, 2000);
tup2 = (1, 2, 3, 4, 5 );
tup3 = "a", "b", "c", "d";

 创建一个空元组：

tup1 = ();

 创建只有一个元素的元组：

tup1 = (50,);

 访问元组的值：

tup1 = ('physics', 'chemistry', 1997, 2000);
tup2 = (1, 2, 3, 4, 5, 6, 7 );

print "tup1[0]: ", tup1[0]
print "tup2[1:5]: ", tup2[1:5]


#result

tup1[0]:  physics
tup2[1:5]:  [2, 3, 4, 5]

 更新元组：

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;

#result

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

 元组的基本操作：

Python Expression Results 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

 

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

 

Python Expression Results Description

L[2]	'SPAM!'	Offsets start at zero
L[-2]	'Spam'	Negative: count from the right
L[1:]	['Spam', 'SPAM!']	Slicing fetches sections

 没有括号的元组：

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


#result

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

 元组与列表的不同是，元组是不可变的，列表是可变的

 

元组包含的方法：

 

Python includes the following tuple functions:

SN 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.