# alpha() function

The alpha() function evaluates the expression
and returns 1 (true) if every character in the string is alphabetical
(that is, a—z upper and lowercase), or 0 (false) if any character
is nonalphabetical.

The empty (null) string ("") is considered
nonalphabetical.

## Syntax

```
alpha(exp)
```

## Parameter(s)

| exp | String to be tested for the existence of alphabetical characters. |
| --- | --- |

## Example(s)

If the value of the variable, `response`, is made up of only alpha characters, it is assigned
to the first element of `array`.

```
if alpha(response) then array(1) = response
```

## See also

- [Boolean evaluation](https://d3codex.com/pickbasic-flashbasic/boolean-evaluation/)
- [BASIC functions](https://d3codex.com/pickbasic-flashbasic/basic-functions/)
- [match relational operator](https://d3codex.com/pickbasic-flashbasic/match-relational-operator/)
- [num() function](https://d3codex.com/pickbasic-flashbasic/num-function/)
- [Statements and functions](https://d3codex.com/pickbasic-flashbasic/statements-and-functions/)

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Source: https://d3codex.com/pickbasic-flashbasic/alpha-function/ - part of the D3Codex reference.