Detect all duplicates from second list based on the numbers in the first list

I have 2 lists, for example:

list1 = [1, 2, 2, 3, 3, 4]
list2 = [1, 1, 2, 2, 3, 3, 4, 4, 4, 5, 5]

I want to get a list 3 which will include all numbers from list2 matching the numbers from list1:

list3 = [1, 1, 2, 2, 3, 3, 4, 4, 4]

I was trying to use 2 while loops to go through list1 and list2 and match numbers, but it gives me wrong number of values:

listO = [1, 2, 2, 3, 3, 4]
listX = [1, 1, 2, 2, 3, 3, 4, 4, 4, 5, 5]
x_temp = []
a = 0
b = 0

while a < len(listO):
       while b < len(listX):
           if listO[a] == listX[b]:
               x_temp.append(listX[b])
               print("Outlier a:" , listO[a] )
               listX.remove(listX[b])
           b+=1
       b=0
       a+=1

list3 = [1, 2, 2, 3, 3, 4, 4]

Is there any way to do it using loops?

• Please do NOT provide solution using set() it doesn`t work for my lists!

Answer

With a for loop:

listO = [1, 2, 2, 3, 3, 4]
listX = [1, 1, 2, 2, 3, 3, 4, 4, 4, 5, 5]
x_temp = []

for x in listX:
    if x in listO:
        x_temp.append(x)

# [1, 1, 2, 2, 3, 3, 4, 4, 4]