You need to do the following data processing using df$\_$zip :

Keep only $5-$digit zip codes in the contbr$\_$zip column.

if zip length is $5-$digit long and all are digits, zip has no change.

if zip is missing, assign it $"99999"$

if zip length is less than $5,$ assign it as $"99999"$

if the length is longer than $5,$ keep only the first $5$ digits only if first $5$ digits exist

After conversion, display:

$(1)$ the total number of rows,

$(2)$ the first $10$ zip$\_$codes, and

$(3)$ last $10$ zip$\_$codes

Hints:

work only on the df$\_$zip

use dataframe or series

need to define function

map$/$apply this function to your data series$/$dataframe$,$

if you use a loop, it will be very slow.