python元组
元组是另一个数据类型，类似于list（列表）。
元组用”()”标识。内部元素用逗号隔开。但是元素不能二次赋值，相当于只读列表。
#!/usr/bin/python
# -*- coding: utf-8 -*-
tuple = ( ‘abcd’, 786 , 2.23, ‘john’, 70.2 )
tinytuple = (123, ‘john’)
print tuple # 输出完整元组
print tuple[0] # 输出元组的第一个元素
print tuple[1:3] # 输出第二个至第三个的元素
print tuple[2:] # 输出从第三个开始至列表末尾的所有元素
print tinytuple * 2 # 输出元组两次
print tuple + tinytuple # 打印组合的元组
以上实例输出结果：
(‘abcd’, 786, 2.23, ‘john’, 70.2)
abcd
(786, 2.23)
(2.23, ‘john’, 70.2)
(123, ‘john’, 123, ‘john’)
(‘abcd’, 786, 2.23, ‘john’, 70.2, 123, ‘john’)
以下是元组无效的，因为元组是不允许更新的。而列表是允许更新的：
#!/usr/bin/python
# -*- coding: utf-8 -*-
tuple = ( ‘abcd’, 786 , 2.23, ‘john’, 70.2 )
list = [ ‘abcd’, 786 , 2.23, ‘john’, 70.2 ]
tuple[2] = 1000 # 元组中是非法应用
list[2] = 1000 # 列表中是合法应用
python逻辑运算符
python语言支持逻辑运算符，以下假设变量a为10，变量b为20：
以下实例演示了python所有逻辑运算符的操作：
#!/usr/bin/python
a = 10
b = 20
c = 0
if ( a and b ):
print “line 1 – a and b are true”
else:
print “line 1 – either a is not true or b is not true”
if ( a or b ):
print “line 2 – either a is true or b is true or both are true”
else:
print “line 2 – neither a is true nor b is true”
a = 0
if ( a and b ):
print “line 3 – a and b are true”
else:
print “line 3 – either a is not true or b is not true”
if ( a or b ):
print “line 4 – either a is true or b is true or both are true”
else:
print “line 4 – neither a is true nor b is true”
if not( a and b ):
print “line 5 – either a is not true or b is not true or both are not true”
else:
print “line 5 – a and b are true”
以上实例输出结果：
line 1 – a and b are true
line 2 – either a is true or b is true or both are true
line 3 – either a is not true or b is not true
line 4 – either a is true or b is true or both are true
line 5 – either a is not true or b is not true or both are not true