table of Contents
set
Unordered (the element position is not fixed), unique (each element is unique), and variable type (the element is variable).
| set | Function method | Annotation |
|---|---|---|
| increase | add | Add elements to the collection. |
| delete | pop | Remove and return any set element. |
| remove | Remove an element from the collection; it must be a member. | |
| change | update | Update the collection with the union of itself and other elements |
1. Definition:
#方法一 直接赋值
>>> set1 = {
1,2,3,4}
>>> type(set1)
<class 'set'>
>>> set1
{
1, 2, 3, 4}
#方法二 s=set()赋值set()
>>> set2 = set()
>>> type(set2)
<class 'set'>
2. Increase
#方法一 .add() 每次只能添加一个元素
>>> set2.add(1)
>>> set2
{
1}
#方法二 .update([元素1，元素2···]) 可以同时添加多个元素
>>> set2.update([2,3,4])
>>> set2
{
1, 2, 3, 4}
3. Delete
#方法一 .pop() 随机删除
>>> set1
{
1, 2, 3, 4, 5}
>>> set1.pop()
1
>>> set1
{
2, 3, 4, 5}
#方法二 .remove(元素) 指定元素删除
>>> set1
{
2, 3, 4, 5}
>>> set1.remove(5)
>>> set1
{
2, 3, 4}
#方法三 .clear()清空集合
>>> set1
{
2, 3, 4}
>>> set1.clear()
>>> set1
set()
4. Change: The set cannot modify the specified element, you can use remove to delete the specified element first, and then add
5. Set operation
| Operator operation | python operator |
|---|---|
| Intersection | & |
| Union | 丨 |
| Subtraction | - |
set1 = {
1,2.5,True,complex(2,3)}
set2 = {
3,3.4,True,complex(1,3)}
print('集合1:',set1)
print('集合2:',set2)
print('交集：',set1&set2)
print('并集：',set1|set2)
print('差集set1-set2：',set1-set2)
print('差集set2-set1：',set2-set1)
结果：
集合1: {
1, 2.5, (2+3j)}
集合2: {
3.4, True, (1+3j), 3}
交集： {
1}
并集： {
1, 2.5, 3.4, 3, (1+3j), (2+3j)}
差集set1-set2： {
2.5, (2+3j)}
差集set2-set1： {
3, (1+3j), 3.4}
dictionary
Note: The key value of the dictionary is unique (cannot be repeated), but the value may not be unique
| dict | Function method | Annotation |
|---|---|---|
| increase | setdefault | Check if you have it, increase if you don't |
| change | update | Change if you have it, increase if you don't |
| delete | pop | Find out the key-value pair of the specified key |
| I drink | Return and delete the last pair of keys and values in the dictionary | |
| check | get | Get the value corresponding to the specified key, if the key does not exist, return it to none |
| keys | Remove all keys | |
| values | Get all the values | |
| items | Take out all the key-value pairs |
1. Definition:
#方法一 di = {key:value}键值对形式
>>> dict={
'name':'zhangsan','age':'18'}
>>> dict
{
'name': 'zhangsan', 'age': '18'}
#方法二 di = {} 直接赋值创建
>>> dict2={
}
>>> type(dict2)
<class 'dict'>
2. Increase
#方法一 di[key] = value di是自己定义的变量名，没有对应的key时为增，有的时候是改
>>> dict2['name']='lisi'
>>> dict2
{
'name': 'lisi'}
#方法二 .setdefault(key,value) 有则查，无则增
>>> dict2
{
'name': 'lisi'}
>>> dict2.setdefault('name','lisi') #name存在，查找name对应值
'lisi'
>>> dict2.setdefault('age','14') #age不存在，添加
'14'
>>> dict2
{
'name': 'lisi', 'age': '14'}
3. Delete
#方法一 .pop(key) 删除指定的值
>>> dict2
{
'name': 'lisi', 'age': '14'}
>>> dict2.pop('age')
'14'
>>> dict2
{
'name': 'lisi'}
#方法二 .popitem() 删除字典最后一对键值对
>>> dict2
{
'name': 'lisi', 'age': '14', 'from': 'hujian'}
>>> dict2.popitem()
('from', 'hujian')
>>> dict2
{
'name': 'lisi', 'age': '14'}
#方法三 .clear() 清空字典
>>> dict2
{
'name': 'lisi', 'age': '14'}
>>> dict2.clear()
>>> dict2
{
}
4. Change
#方法一 .update ({key:value}) 有则改，无则添加
>>> dict
{
'name': 'zhangsan', 'age': '20'}
>>> dict.update({
'age':'18'}) #age存在，修改age的value
>>> dict
{
'name': 'zhangsan', 'age': '18'}
>>> dict.update({
'high':'178'}) #high不存在，添加high
>>> dict
{
'name': 'zhangsan', 'age': '18', 'high': '178'}
5. Check
#方法一 .[key] 查找显示所有的key值
>>> dict
{
'name': 'zhangsan', 'age': '18', 'high': '178'}
>>> dict.keys()
dict_keys(['name', 'age', 'high'])
#方法二 .get(key) 获取指定key对应的value
>>> dict
{
'name': 'zhangsan', 'age': '18', 'high': '178'}
>>> dict.get('name')
'zhangsan'
#方法三 .values() 查找显示所有的value值
>>> dict
{
'name': 'zhangsan', 'age': '18', 'high': '178'}
>>> dict.values()
dict_values(['zhangsan', '18', '178'])
#方法四 .items() 显示所有键值对
>>> dict
{
'name': 'zhangsan', 'age': '18', 'high': '178'}
>>> dict.items()
dict_items([('name', 'zhangsan'), ('age', '18'), ('high', '178')])