python基础之列表、元组

一、列表

列表（list）是我们最以后最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

作用：多个装备，多个爱好，多门课程，多个女朋友等

定义：[ ]内可以有多个任意类型的值，逗号分隔

定义列表：name = [ ]   #name等于中括号就是定义列表

列表用来存储数据的

1、基本操作

2、定义列表

name = ['tom','jack','ren','yan']
print(type(name))
-------------------------------------------------
<class 'list'>

3、遍历列表

name = ['tom','jack','ren','yan']
for i in name:
    print(i)
-------------------------------------
tom
jack
ren
yan
---------------------------------------------------
#通过下标访问
print(name[0])
print(name[3])
--------------------------------
tom
yan

4、切片：取多个元素

name = ['tom','jack','ren','yan','zhong','qq','weixin']
print(name[0:3])　　#取下标0至3之间的元素，包含0，不包含3
print(name[:3])　　
print(name[:-1])　　#取下标0至最后一个的元素，包含0，不包含-1
print(name[4:])
print(name[::2])　　#2表示每隔一个元素，就取一个
print(name[0:4:2])　　#在0到4之间每隔一个元素取一个
------------------------------------------------------------
['tom', 'jack', 'ren']
['tom', 'jack', 'ren']
['tom', 'jack', 'ren', 'yan', 'zhong', 'qq']
['zhong', 'qq', 'weixin']
['tom', 'ren', 'zhong', 'weixin']
['tom', 'ren']

5、追加

name = ['tom','jack','ren','yan']
print(name)
name.append('我是新来的')　　#在列表的尾部加入指定的元素
print(name)
-------------------------------------------------------------
['tom', 'jack', 'ren', 'yan']
['tom', 'jack', 'ren', 'yan', '我是新来的']

6、插入

name = ['tom','jack','ren','yan']
print(name)
name.insert(1,'插队的')　　#插入到索引1位置
print(name)
---------------------------------------------
['tom', 'jack', 'ren', 'yan']
['tom', '插队的', 'jack', 'ren', 'yan']

7、修改

name = ['tom','jack','ren','yan']
print(name)
name[1] = '该换人了'
print(name)
-------------------------------------------------
['tom', 'jack', 'ren', 'yan']
['tom', '该换人了', 'ren', 'yan']

8、删除

name = ['tom','jack','ren','yan','zhong','hello','go','python']
del name[0]　　#删除索引为0的指定元素
print(name)　　#tom已删除
print(name.pop(0))　　#输出要剪切的指定元素（知道索引，不知道内容）
print(name)　　#Jack已删除
print(name.pop())　　#pop默认删除最后一个元素
print(name)
print(name.remove('ren'))　　#删除指定元素，且不输出（知道内容不知道索引）
print(name)
---------------------------------------------------------
['jack', 'ren', 'yan', 'zhong', 'hello', 'go', 'python']
jack
['ren', 'yan', 'zhong', 'hello', 'go', 'python']
python
['ren', 'yan', 'zhong', 'hello', 'go']
None
['yan', 'zhong', 'hello', 'go']

9、扩展

name = ['tom','jack','ren','yan','zhong']
languages = ['pyhon','go','C#','PHP']
name.extend(languages)
print(name)
--------------------------------------------
['tom', 'jack', 'ren', 'yan', 'zhong', 'pyhon', 'go', 'C#', 'PHP']

10、拷贝

name = ['tom','jack','ren','yan','zhong']
name_copy = name.copy()
print(name_copy)
--------------------------------------------------
['tom', 'jack', 'ren', 'yan', 'zhong']

11、统计

name = ['tom','ren','ren','yan','zhong']
print(name.count('ren'))
----------------------------------------------------
2

12、排序&翻转

name = ['tom','ren','ren','yan','zhong','alex',1,12,2,3,23]
name.sort()    #不同字符类型不能放在一起排序
print(name)
-------------------------------------
Traceback (most recent call last):
  File "C:/Users/renyz02/Desktop/py_test1/20190911/list.py", line 76, in <module>
    name.sort()
TypeError: '<' not supported between instances of 'int' and 'str'

name = ['tom','ren','ren','yan','zhong','alex']
print(name)
name.sort()　　#排序（字母按照ASCII码，数字从小到大）
print(name)
name.reverse()　　#反转原来的顺序（数字、字母同理）
print(name)
-----------------------------------------------------
['tom', 'ren', 'ren', 'yan', 'zhong', 'alex']
['alex', 'ren', 'ren', 'tom', 'yan', 'zhong']
['zhong', 'yan', 'tom', 'ren', 'ren', 'alex']
----------------------------------------------------------------
name = ['tom','ren','ren','yan','zhong','alex']
print(name)
# name.sort()
# print(name)
name.reverse()
print(name)
--------------------------------------------------
['tom', 'ren', 'ren', 'yan', 'zhong', 'alex']
['alex', 'zhong', 'yan', 'ren', 'ren', 'tom']

13、获取下标

name = ['tom','ren','ren','yan','zhong','alex']
print(name.index('yan'))
---------------------------------------------------
3

二、元组

另一种有序列表叫元组：tuple。tuple和list非常类似，但是tuple一旦初始化就不能修改

元组特点：是不可变

定义：与列表类型比，只不过[  ]换成() ，如：age=(11,22,33,44,55)

作用：存多个值，对比列表来说，元组不可变（是可以当做字典的key的）

1、创建元组

num = (11,22,33,44)
print(type(num))
print(num)
----------------------------------------------
<class 'tuple'>
(11, 22, 33, 44)

定义一个空的tuple，可以写成（）：

num2 = ()
print(type(num2))
--------------------------------------------
<class 'tuple'>

但是，如果定义一个只有一个元素的tuple，需要加，：

num3 = (22)
print(type(num3))
num4 = (22,)
print(type(num4))
-----------------------------------------------------------
<class 'int'>
<class 'tuple'>

2、访问元组

num = (11,22,33,44)
print(num)
print(num[2])
-----------------------------------------
(11, 22, 33, 44)
33

num = (11,22,33,44)
print(num)
print(num.index(44))　　#取索引
print(num.count(22))　　#计数
-------------------------------------------------
(11, 22, 33, 44)
3
1

3、修改元组

说明：Python中不允许修改元组的数据，包括不能删除其中的元素。

元组是不可变的，也就是说，元组中的元素在被赋值后不能改变。但是，如果元素本身是一个可变数据类型的列表，那么其嵌套项可以被改变。

aa = (1,2,[11,22,33])
print(id(2))　　#查看id
aa[2][0] = 44
print(aa)
print(id(2))　　#id是一致的
--------------------------------------------------------
140730237805232
(1, 2, [44, 22, 33])
140730237805232

4、多维元祖访问

person = (("刘备","关羽","张飞"),("曹操","典韦"),("孙权","周瑜"))
print(person[2])
print(person[0][0])
-----------------------------------------------------
('孙权', '周瑜')
刘备