Numbers

Integers

Integers have no fixed size in Elixir, so huge counts never overflow into strange values. Underscores may separate digit groups for readability and change nothing about the value:

count = 1_000 IO.puts(count + 1) # prints 1001 10 * 1_000_000 # gives 10000000

Floats

Floats carry a decimal point and follow the usual 64 bit format. The slash operator always returns a float, even when the division comes out even:

pi = 3.14 7 / 2 # gives 3.5 4 / 2 # gives 2.0 rather than 2

div rem div

For integer division and remainders, call div and rem instead of using the slash. div drops the fraction while rem keeps the remainder:

div(7, 2) # gives 3 rem(7, 2) # gives 1 div(7, 3) + rem(7, 3) # gives 3

To_string and to_integer

Numbers and strings never mix on their own, so convert values at the boundary. Integer.to_string/1 builds a string while String.to_integer/1 parses one back:

Integer.to_string(42) # gives "42" String.to_integer("42") # gives 42

A string with extra characters raises an ArgumentError, so parse only clean input.

Next: Strings

Article author: Arthur Isaev