Picking repeated adjacent numbers in a list

May 20, 2022

I want to enter a group of numbers, and my output to be a list of the numbers that are repeated more than once, side by side.

Example input: 1,1,2,2,1,1,1,3,4,5,5,-1,-1,-1,3,4,3

Wanted output: [1,2,1,5,-1]

My code:

countnumbers = []
numbers = input().split(',')

for i in range(len(numbers)):
    numbers[i] = int(numbers[i])

sizeoflist = len(numbers)
  
for i in range(sizeoflist - 1):
    if numbers[i] == numbers[i + 1]:
        countnumbers.append(numbers[i])
                
mylist = str(countnumbers).replace(' ','')
print(mylist)

Example for what my code generates:

Input: 1,1,1,2,2,1,1,1

Output: [1,1,2,1,1]

So I’m just struggling in how to make it [1,2,1].
I know my code is faulty, I tried using the count function, to count but didn’t work for me.
And please without the def calling function.

>Solution :

Add a way to remember last known number:

countnumbers = []
numbers = input().split(',')

for i in range(len(numbers)):
    numbers[i] = int(numbers[i])

sizeoflist = len(numbers)

current = None
for i in range(sizeoflist - 1):
    if numbers[i] == numbers[i + 1]:
        if current is None:
            current = numbers[i]
            countnumbers.append(numbers[i])
    else:
        current = None

mylist = str(countnumbers).replace(' ','')
print(mylist)

notice how i used current variable