[FIXED] Python - Remove Rows Based Specific Values

Issue

I'm having some difficulty removing rows based on certain criteria. In this case, there is a row with column ID and Code. If a Code is 26 and that is the only row for an ID, then the entire existence of that ID should be removed.

In the below case, only ID 124 was removed. Even though ID 125 has Code 26, it has a NULL value. I have many more columns in my dataset, but these are the only two rows of concern.

Input

ID   Code  
111  2     
111  5     
111  23    
123  27
123  3
124  26  
125  8
125  26
126  26
126  NULL

Output

ID   Code  
111  2     
111  5     
111  23    
123  27
123  3
125  8
125  26
126  26
126  NULL

Solution

Here's a boolean index version:

df = df[df['ID'].duplicated(keep=False) | (df['Code'] != 26)]

Keep rows where the ID is duplicated OR where the code is not equal to 26 (single IDs with the code 26 are removed). Result:

    ID  Code
0  111   2.0
1  111   5.0
2  111  23.0
3  123  27.0
4  123   3.0
6  125   8.0
7  125  26.0
8  126  26.0
9  126   NaN

Answered By - Tom