python 列表、元组操作

列表是我们常用的数据类型之一，通过列表可以对数据实现最方便的存储、修改等操作

定义列表:

names = ['stone1','stone2','stone3']

通过下标访问列表中的元素，下标从0开始计数

 names[0]   对应  stone1

 names[1]   对应  stone2

 names[2]   对应  stone3

 names[-1]   对应  stone3

 names[-2]   对应  stone2

 

取多个元素

names[0:2]    names[:2] #如果是从头开始取，0可以忽略

['stone1','stone2']

names[1:]  #如果想取最后一个，必须不能写-1，只能这么写

['stone2','stone3']

names[0::2]#后面的2是代表，每隔一个元素，就取一个

['stone1','stone3']

 

追加

names = ['stone1','stone2','stone3']

names.append("stone4")

>>>names

 ['stone1','stone2','stone3','stone4']

 

插入

names = ['stone1','stone2','stone3']

names.insert(2,'stone4')

>>>names

['stone1'，'stone2','stone4','stone3']

 

修改

 names = ['stone1','stone2','stone3']

names[1] = 'stone4'

>>>names

['stone1','stone4','stone3']

 

删除

 names = ['stone1','stone2','stone3']

del names[1]

>>>names

['stone1','stone3']

>>>

names = ['stone1','stone2','stone3']

names.remove('stone1')　　#删除指定元素

>>>names

['stone2','stone3']

>>>

names = ['stone1','stone2','stone3']

names.pop() #删除列表最后一个值

'stone3'

>>>names

['stone1','stone2']

 

扩展

names = ['stone1','stone2','stone3']

b = [1,2,3]

names.extend(b)

>>>names

['stone1','stone2','stone3',1,2,3]

 

拷贝

names = ['stone1','stone2','stone3']

names_copy = names.copy()

>>>names_copy

['stone1','stone2','stone3']

 

统计

names = ['stone1','stone2','stone3','stone1','stone1']

names.count('stone1')

3

 

排序&反转

names = ['stone1','stone2','stone3',1,2,3]

names.sort()

TypeError:unorderable types: int() < str() #3.0不同数据类型不能排序

names = ['stone1','stone2','stone3','1','2','3']

names.sort()

>>>names

['1','2','3','stone1','stone2','stone3']

names.reverse()

>>>names

['stone3','stone2','stone1','3','2','1']

 

获取下标

names = ['stone1','stone2','stone3','1','2','3'] #只返回找到的第一个下标

names.index('stone2')

1

 

元组

元组其实跟列表差不多，也是存一组数，它一旦创建，便不能再修改，所以又叫只读列表

names = ('stone1','stone2','stone3')

>>>names.count('stone1')

1

>>>names.index('stone3')

2