python, sql join code example

Example 1: SQL joins in python

This was What I intended
 ID Case NxtCase
 1    A        
 2    C        
 3    E      

This is my desired result

 ID Case NxtCase
 1    A        B
 2    C        D
 3    E        F

Example 2: join() python

# example of join() function in python

numList = ['1', '2', '3', '4']
separator = ', '
print(separator.join(numList))