Not the most efficient one, but by far the most obvious way to do it is:

>>> a = [1, 2, 3, 4, 5]
>>> b = [9, 8, 7, 6, 5]
>>> set(a) & set(b)
{5}

if order is significant you can do it with list comprehensions like this:

>>> [i for i, j in zip(a, b) if i == j]
[5]

(only works for equal-sized lists, which order-significance implies).

Hi Rental,

Thanks for contacting us,

Yes, you can use Excel to compare two lists and identify what is unique in each list. Here are the steps:

Method 1: Using Formulas

1. **Combine the Lists:**
   • Suppose your old inventory is in column A (A2:A100) and the current inventory is in column B (B2:B100).
   • In column C, combine both lists using the following formula in cell C2 and drag it down:

     =IFERROR(IF(MATCH(B2, $A$2:$A$100, 0), ""), B2)
     ```

This formula checks if the item in the current inventory list (column B) is found in the old inventory list (column A). If not, it returns the item; otherwise, it returns an empty string.

2. \*\*Filter the Unique Entries:\*\*
   - Filter column C to show only the non-empty cells. These are the items that are unique to the current inventory list.

3. \*\*Repeat the Process:\*\*
   - Repeat the process in column D but comparing the old inventory list to the current inventory list. Use a similar formula:

```excel
     =IFERROR(IF(MATCH(A2, $B$2:$B$100, 0), ""), A2)
     ```

Filter column D to show only the non-empty cells. These are the items that were present in the old inventory list but are not in the current one.

Method 2: Using Conditional Formatting

1. \*\*Highlight Differences:\*\*
   - Select the old inventory list (column A) and then the current inventory list (column B).
   - Go to the "Home" tab, click on "Conditional Formatting," and choose "Highlight Cells Rules" -> "Duplicate Values."
   - This will highlight the items that appear in both lists.

2. \*\*Filter Unique Entries:\*\*
   - Use the "Filter" option to filter out the highlighted cells in both columns. The remaining items in column A are those unique to the old inventory list, and the remaining items in column B are those unique to the current inventory list.

Choose the method that suits you best based on your preferences and requirements.

I hope this helps!

Regards,
Sola