# ! operator

Source: https://ref.dm-lang.org/operator/exclaim

### Format
> `!A`

### Returns
> 1 if A is a false value (zero, an empty string, or null); 0 otherwise.

This operator inverts the truthiness of the value after it.

The number 0, an empty string, or null are all false values. Everything else is true.

### See also
- [&& operator](https://ref.dm-lang.org/operator/ampamp.md)
- [operators](https://ref.dm-lang.org/operator/index.md)
- [|| operator](https://ref.dm-lang.org/operator/vertvert.md)