if and cond in Elixir

Both conditionals return values: if for two branches, cond for a ladder of tests.

# if is an expression: both branches hand back a value.
depth_ft = 23
note = if depth_ft > 30, do: "bring the long rope", else: "day trip"
IO.puts(note)

# cond picks the first branch whose condition is truthy.
visibility_ft = 8

rating =
  cond do
    visibility_ft >= 30 -> "gin clear"
    visibility_ft >= 15 -> "workable"
    true -> "silted out"
  end

IO.puts("cave rating: #{rating}")

How it works

if is an expression, so note receives whichever branch runs.
cond do walks the visibility tests top to bottom and stops at the first truthy one.
true -> is the catch-all rung, playing the role of else.

Keywords and builtins used here

IO
cond
do
end
if

The run, in numbers

Lines: 16
Characters to type: 375
Tokens: 67
Three-star pace: 75 tpm

At the three-star pace of 75 tokens a minute, this run takes about 54 seconds.

Type this snippet

Step 1 of 3 in Control flow, step 19 of 27 in Language basics.

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