# Boolean values

Sidef defines the *true* and *false* boolean values, which are part of the *Bool* type.

```ruby
var t = true
var f = false
```

In conditional expressions, anything that evaluates to zero or nothing is considered *false*, including empty arrays and empty hashes.

```ruby
if (0 || "0" || false || nil || "" || [] || :()) {
    say "true"
} else {
    say "false"
}
```

#### Output:

```
false
```