python-6列表和元组
序列
索引
| 元素1 | 元素2 | 元素3 | 元素4 | 元素5 | 元素6 |
|---|---|---|---|---|---|
| 0 | 1 | 2 | 3 | 4 | 5 |
| -6 | -5 | -4 | -3 | -2 | -1 |
verse = ["LSF","LYF","LJZ","ZSF","YX"]
print(verse[0])
print(verse[-1])
print(verse[1])
LSF YX LYF
切片
sname[strart :end;step]
end不包括本事
strp步长默认为1，可以省略
verse = ["LSF","LYF","LJZ","ZSF","YX"]
print(verse[0:4:3])
[‘LSF’, ‘ZSF’]
注意：复制整个系列用
print(verse[:])即可
序列相加
不同元素类型也可以相加，但是序列和元组和字符串不能相加
verse = ["LSF","LYF","LJZ","ZSF","YX"]
football = ["axle","cl","mx"]
luckynum = [3,10,33]
print(verse+football)
print(football+luckynum)
结果：[‘LSF’, ‘LYF’, ‘LJZ’, ‘ZSF’, ‘YX’, ‘axle’, ‘cl’, ‘mx’]
[‘axle’, ‘cl’, ‘mx’, 3, 10, 33]
乘法
family = ["LSF","LYF","LJZ","ZSF","YX"]
football = ["axle","cl","mx"]
luckynum = [3,10,33]
print(family*2)
[‘LSF’, ‘LYF’, ‘LJZ’, ‘ZSF’, ‘YX’, ‘LSF’, ‘LYF’, ‘LJZ’, ‘ZSF’, ‘YX’]
可以用乘法生成指定长度列表
查询元素是否在序列中
value in sequence
value 表示元素，sequence表示序列
family =["lsf","zyy","yx","lyf","zsf","ljz",6,8,33]
print("zyy" in family)
print(33 in family)
Ture Ture
注意：字符串要用引号
计算序列的长度、最大值和最小值
family =["lsf","zyy","yx","lyf","zsf","ljz",6,8,33]
print("序列family的长度是：",len(family))
print("序列family的长度是："+str(len(family)))
序列family的长度是： 9
序列family的长度是：9
family =[66,6,8,33,23,44,67]
print("序列",family,"中的最大值是：",max(family),"/""序列",family,"的最小值是",min(family))
序列 [66, 6, 8, 33, 23, 44, 67] 中的最大值是： 67 /序列 [66, 6, 8, 33, 23, 44, 67] 的最小值是 6
python提供的内置函数
| 函数 | 说明 |
|---|---|
| len() | 求序列长度 |
| max() | 求最大值 |
| min() | 求最小值 |
| list() | 将序列转化成列表 |
| str() | 将序列转换成字符串 |
| sum() | 计算元素和 |
| sorted() | 对元素进行排序 |
| reversed | 反向序列中的元素 |
| enumerate() | 将序列组合成一个索引序列，用于for循环 |
family =[66,6,8,33,23,44,67]
u=str(family)
print(type(u))
print(sorted(family))
print(list(reversed(family))) //reversed返回的是一个迭代器，用list
[6, 8, 23, 33, 44, 66, 67]
[67, 44, 23, 33, 8, 6, 66]
列表
列表创建和删除
1、直接创建
listname = [element1,element2,element3,…]
2、创建空列表
emptylist= []
3、数值列表
list(data)
data可以是range对象，字符串，元组，其他可迭代类型的数据
ab = list(range(1,10,3))
print(ab)
[1, 4, 7]
4、删除列表
del listname
访问列表元素
family =["lsf","zyy","yx","lyf","zsf","ljz",6,8,33]
print(family)
print(family[1:10:2])
[‘lsf’, ‘zyy’, ‘yx’, ‘lyf’, ‘zsf’, ‘ljz’, 6, 8, 33]
[‘zyy’, ‘lyf’, ‘ljz’, 8]
遍历列表
1、用for循环实现
for name in listname
print(name)
family =["lsf","zyy","yx","lyf","zsf","ljz",6,8,33]
for familyname in family:
print(familyname)
lsf
zyy
yx
lyf
zsf
ljz
6
8
33
name = "python"
for name1 in name:
print(name1)
p
y
t
h
o
n
2、使用for和enumerate
for index,name in enumerate(listname)
print(index,name)
for index,pyl in enumerate("python"):
print(index,pyl)
0 p
1 y
2 t
3 h
4 o
5 n
family =["lsf","zyy","yx","lyf","zsf","ljz",6,8,33]
for index , familyname in enumerate(family):
print(index+1,familyname)
1 lsf
2 zyy
3 yx
4 lyf
5 zsf
6 ljz
7 6
8 8
9 33
添加、修改、删除列表元素
1、添加元素
listname.append(obj) //添加一个元素
family =["lsf","zyy","yx","lyf","zsf","ljz"]
family.append("lef")
print(family)
[‘lsf’, ‘zyy’, ‘yx’, ‘lyf’, ‘zsf’, ‘ljz’, ‘lef’]
listname.extend(seq) //添加列表
family =["lsf","yx","lyf","zsf","ljz"]
fk =["zyy","zyq","zfr","lxb"]
family.extend(fk)
print(family)
[‘lsf’, ‘yx’, ‘lyf’, ‘zsf’, ‘ljz’, ‘zyy’, ‘zyq’, ‘zfr’, ‘lxb’]
2、修改元素
修改元素只需要通过索引获取元素后，重新给他赋值就可以了
family =["lsf","yx","lyf","zsf","ljz"]
print(family)
family[2] ="lyf and lef"
print(family)
[‘lsf’, ‘yx’, ‘lyf’, ‘zsf’, ‘ljz’]
[‘lsf’, ‘yx’, ‘lyf and lef’, ‘zsf’, ‘ljz’]
3、删除元素
family =["lsf","yx","lyf","zsf","ljz"]
print(family)
del family[1]
print(family)
[‘lsf’, ‘yx’, ‘lyf’, ‘zsf’, ‘ljz’]
[‘lsf’, ‘lyf’, ‘zsf’, ‘ljz’]
删除不确定位置的函数用remove
family =["lsf","yx","lyf","zsf","ljz"]
print(family)
family.remove("yx"):
print(family)
[‘lsf’, ‘yx’, ‘lyf’, ‘zsf’, ‘ljz’]
[‘lsf’, ‘lyf’, ‘zsf’, ‘ljz’]
思考：如果是有2个yx怎么处理？
首先判断元素是否在里面
family =["lsf","yx","lyf","zsf","ljz"]
print(family)
LZ= "lsf" in family
if LZ == True:
family.remove("yx")
print(family)
[‘lsf’, ‘yx’, ‘lyf’, ‘zsf’, ‘ljz’]
[‘lsf’, ‘lyf’, ‘zsf’, ‘ljz’]
列表中数据统计
1、获取指定元素出现的次数
listname.count(obj)
family =["lsf","yx","lyf","zsf","ljz","yx"]
num = family.count("yx")
print(num)
2
2、获取指定元素首次出现的下标
listname.index(obj)
family =["lsf","yx","lyf","zsf","ljz","yx"]
index1 = family.index("yx")
print(index1)
1
3、统计数值列表的元素和
sum(iterable[,start])
num1 = [1,2,3,4,5,6,7,8,9]
sumnum = sum(num1[1:5])
print(sumnum)
14
对列表进行排序
1、使用列表对象sort()方法实现
listname.sort(key=None,reverse=False
num1 = [1,7,5,15,66,2]
num1.sort()
print(num1)
num1.sort(reverse=True)
print(num1)
[1, 2, 5, 7, 15, 66]
[66, 15, 7, 5, 2, 1]
char = ["zyy","zyq","yx","lxb","Zfr"]
char.sort()
print(char)
char.sort(key=str.lower)
print(char)
[‘Zfr’, ‘lxb’, ‘yx’, ‘zyq’, ‘zyy’]
[‘lxb’, ‘yx’, ‘Zfr’, ‘zyq’, ‘zyy’]
2、使用内置的sorted()函数实现
num1 = [1,7,5,15,66,2]
num =sorted(num1,reverse=True)
num2= sorted(num1)
print(num)
print(num2)
[66, 15, 7, 5, 2, 1]
[1, 2, 5, 7, 15, 66]
sort()和sorted()功能都是一样的，但是sorted要建立一个新的副本，
列表推导式
用于快速生成列表
1、指定范围
list = [Expression for var in range]
import random
rdnum =[random.randint(1,100) for i in range(5)]
print(rdnum)
2、根据列表生成指定需求列表
newlist = [Expression for var in list]
price = [100,40,35,27,40]
sale =[x*0.5 for x in price]
print((sale))
[50.0, 20.0, 17.5, 13.5, 20.0]
3、旧列表中选择符合条件的元素添加到新列表
newlist = [Expression for var in list if condition]
price = [100,50,70,60,30]
sale = [x for x in price if x>50]
print(sale)
[100, 70, 60]
元组
1、创建元组
tuplename = (element1, element2,element3,…)
用小括号，也可以不用，只要有逗号隔开即可
family1 =("lsf")
family2 =("lsf",)
print(type(family1))
print("类型是：",type(family2))
类型是：
注意逗号
2、创建空元组
emptytuple =()
3、创建数组
tuplename = tuple(range(10,20,3))
print(tuplename)
(10, 13, 16, 19)
4、删除元组
del tuplaname
5、访问元组
print(tuplename)
print(tuplename[2])
列表和元组的区别
1列表属于可变序列，元组不能
2列表可以使用append()、extend() instrat() remove()和pop()等方法，元组不能
3 列表可以切片和修改，元组可以切片
4 元组比列表访问更快，
5 列表不能作为字典的建
1、实战任务
year = [89,98,00,75,68,37,58,90] # 原有的年份列表
for index,value in enumerate(year): # 遍历列表元素索引与年份
if str(value)!='0': # 判断非0年份
year[index]=int('19'+str(value))
else:
year[index]=int('200'+str(value)) # 判断2000年
print(year) # 打印修改后的年份列表
[1989, 1998, 2000, 1975, 1968, 1937, 1958, 1990]