Python little exercise: Given a list of non-empty and positive integers, sort the output in descending order of repetition

Suppose there is a list a=[1,1,1,2,2,4,5,5,5,5] (not empty and a positive integer)

Then the final output is in the form of 5,1,2,4 (the output is sorted in descending order of repetition)

Code implementation and interpretation:

a=[1,1,1,2,2,4,5,5,5,5]
Num=[]

For I in A:
    s = A.count (i)
    Num.append (s) #取出数字出现的次数 put into num

NUM1 = sorted (num,reverse=true) # arranges num in descending order and assigns a value to NUM1
Num2=list (Set (NUM1)) #去重并转换成列表类型  (Note: The element display is unordered after de-weight)

Num2.sort (Key=num1.index) #按原来num1的顺序排序 (This step is critical for the value in the a list that ultimately outputs as required)
Num3=[]

For x in num2:
    For I in A:
        If x ==a.count (i):
            Num3.append (i) #取出次数对应a列表里面的值放进新列表num3中 the elements in the num3 are the same as the elements in a list except that the  order is displayed in repetitions and the  elements have duplicate values
        Else
            Pass
Num4=[]
For J in Num3:
    If J not in NUM4:
        Num4.append (j) #去重
Print (NUM4)

The final output is: [5, 1, 2, 4]

Here's a list of knowledge points to go back to and sort by the original order:

Num2=list (Set (NUM1)) #去重并转换成列表类型  (Note: The element display is unordered after de-weight)

Num2.sort (Key=num1.index) #按原来num1的顺序排序 (This step is critical for the value in the a list that ultimately outputs as required)

Python little exercise: Given a list of non-empty and positive integers, sort the output in descending order of repetition