Course of Raku / Advanced / More about built-in types / Sequences / Exercises / Powers of two

Solution: Powers of two

Here is a possible solution to the task.

Code

say (1, 2, 4 ... Inf).head(8);

🦋 You can find the source code in the file powers-of-two.raku.

Output

(1 2 4 8 16 32 64 128)

Comments

1. The three starting values 1, 2, 4 grow by multiplication, so ... recognises a geometric sequence; with Inf as the endpoint it never stops on its own.

2. head(8) pulls only the first eight values. Because the sequence is lazy, the rest are never generated — which is the only reason an infinite sequence is safe to write.

Course navigation

← Powers of two   |   The last three →