Absolute value

The absolute value function applied to a number x can be written either abs(x) or using the traditional notation |x|.

Disco> abs(6)
6
Disco> abs(-6)
6
Disco> abs(-1/2)
1/2
Disco> |-6|
6

Since the output of abs is always positive, it can convert rational numbers into fractional numbers, and integers into natural numbers.

The notation |~| can also be used to find the size of a collection such as a set, bag, or list.