arr = []
for sub_row in df1['Col']:
    for idx, row in df2.iterrows():
         if '/' in sub_row:
             sub_row= sub_row.split('/')[1]
          if sub_row == row['x2']:
               arr.append(row['cod'])
          elif sub_row == row['x3']:
               arr.append(row['cod'])
          elif sub_row == row['x4']:
               arr.append(row['cod'])
df1['cod'] = cod