The Queue block

What it does

Uses a list as a queue, like a line at a counter: enqueue joins the back, dequeue serves the front. The first one in is the first one out.

Use it for

• Serving people in the order they came.
• Print jobs, messages, tasks: first come, first served.
• Taking turns in a game.

What to fill in

What to do

Enqueue a value at the back, Dequeue the front one, or Peek at the front one without taking it.

Which queue

A list, made first with Create Value: line = [].

Add to the back

The value that joins, like "Arun" (for Enqueue).

Keep it in

A name for the one served or looked at, like next (for Dequeue and Peek).

Try it

Open it in the editor, press Run, then change it and run it again.

1line = []2line.append("Arun")3line.append("Priya")4line.append("Kavin")5next = line.pop(0)6print("Serving " + next)7print("Still waiting: " + ", ".join(line))