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当你不知道用什么数据类型的时候,一定要记得list,大多数的脏活累活ta都帮你搞定



列表list

定义

list是一种有序的集合,内部可以由任何数据类型的组成的

现在有5位员工的汇总信息,

id 姓名 年龄 性别 爱好
1 David 25 Male Basketball, Pingpang, Hiking
2 Mary 23 Female Reading, Movies
3 Henry 23 Male Diving, Hiking
4 Swift 21 Male Football, Music
5 Lenard 26 Male Stay at Home

现在我们需要用一种格式去组织5位员工的信息,以列表为例

names = ['David', 'Mary', 'Henry', 'Swift', 'Lenard']

ages = [25, 23, 23, 21, 26]

hobbies = [['Basketball', 'Pingpang', 'Hiking'],
          ['Reading', 'Movies'],
          ['Diving', 'Hiking'],
          ['Football', 'Music'],
          ['Stay at Home']]

print(type(names))
print(type(ages))
print(type(hobbies))

print(names)
print(ages)
print(hobbies)
<class 'list'>
<class 'list'>
<class 'list'>
['David', 'Mary', 'Henry', 'Swift', 'Lenard']
[25, 23, 23, 21, 26]
[['Basketball', 'Pingpang', 'Hiking'], ['Reading', 'Movies'], ['Diving', 'Hiking'], ['Football', 'Music'], ['Stay at Home']]

**多想一下: **组织数据的方式有很多种,list也可以用不同的方式去组织,大家可以自己想一想。



拼接

a1 = ['Michael', 'Bob']
a2 = ['David', 'Lee']

print(a1 + a2)
print(a2 + a1)
['Michael', 'Bob', 'David', 'Lee']
['David', 'Lee', 'Michael', 'Bob']



拆包

注意: 等号两边长度相同

name, age = ['David', 25]
print(name)
print(age)
David
25



切片

列表的切片与字符串类似

id 姓名 年龄 性别 爱好 正索引 倒索引
1 David 25 Male Basketball, Pingpang, Hiking 0 -5
2 Mary 23 Female Reading, Movies 1 -4
3 Henry 23 Male Diving, Hiking 2 -3
4 Swift 21 Male Football, Music 3 -2
5 Lenard 26 Male Stay at Home 4 -1
names = ['David', 'Mary', 'Henry', 'Swift', 'Lenard']
names
['David', 'Mary', 'Henry', 'Swift', 'Lenard']

print(names[2])
print(names[-3])
Henry
Henry

print(names[0:3])
print(names[-5:-2])
['David', 'Mary', 'Henry']
['David', 'Mary', 'Henry']

print(names[2:])
print(names[-3:])
['Henry', 'Swift', 'Lenard']
['Henry', 'Swift', 'Lenard']

print(names[:2])
print(names[:-3])
['David', 'Mary']
['David', 'Mary']

列表常用方法

常用方法 功能
list.append(a) 向list中添加元素a
list.extend(lst) 向list中添加列表lst
list.count(a) 统计list中a的个数
names = ['David', 'Mary', 'Henry', 'Swift', 'Lenard']

print(names)
names.append('Mary')
print(names)
['David', 'Mary', 'Henry', 'Swift', 'Lenard']
['David', 'Mary', 'Henry', 'Swift', 'Lenard', 'Mary']

names = ['David', 'Mary', 'Henry', 'Swift', 'Lenard']

print(names)

names.extend(['Mary'])

print(names)
['David', 'Mary', 'Henry', 'Swift', 'Lenard']
['David', 'Mary', 'Henry', 'Swift', 'Lenard', 'Mary']


ages = [25, 23, 23, 21, 26]
print(ages.count(23))
2

one = ['David']
print(one[-1])
print(one[0])
David
David



元组tuple

形似列表,也有

  • 元组拼接
  • 切片
  • 拆包
name_list = ['David', 'Mary', 'Henry', 'Swift', 'Lenard']
name_tuple = ('David', 'Mary', 'Henry', 'Swift', 'Lenard')

print(type(name_list))
print(type(name_tuple))

print(name_list)
print(name_tuple)
<class 'list'>
<class 'tuple'>
['David', 'Mary', 'Henry', 'Swift', 'Lenard']
('David', 'Mary', 'Henry', 'Swift', 'Lenard')

print(name_list==name_tuple)
False



集合

names2 = ['David', 'Mary', 'David', 'Swift', 'David']
print(set(names2))
{'Swift', 'Mary', 'David'}

集合的方法

  • setdata.add(ele) 向setdata中加入ele
name_set = set(names2)

print(name_set)

name_set.add('William')

print(name_set)
{'Swift', 'Mary', 'David'}
{'William', 'Swift', 'Mary', 'David'}

name_set[2]
---------------------------------------------------------------------------

TypeError                                 Traceback (most recent call last)

<ipython-input-20-98cb669cc173> in <module>
----> 1 name_set[2]


TypeError: 'set' object is not subscriptable

注意: 集合不能切片




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