erlang - Handling the return of the queue:out

i have statement want remove last item in queue using out_r.

the docs return

result = {{value, item}, q2} | {empty, q1}
q1 = q2 = queue()

how handle if want queue item removed?

how queue , disregard {value, item}?

e.g. newqueue = queue:out_r(oldqueue)

thanks

use pattern matching!

{_, newqueue} = queue:out_r(oldqueue)

given both {value, item} , empty returned first element of tuple, ignoring first element want.

note queue module supports 3 apis. other apis might want better. in case, can have same function, except crashes if queue empty:

drop_r(q1) -> q2 returns queue q2 result of removing rear item q1. fails reason empty if q1 empty.

picking 1 or other depends on applications , expect in queue, if can handle empty one, etc.

shell