php regular expression. Alphabet with spaces only after the first word

Question

What is a php regular expression that will allow letters and spaces. But spaces only after the first word? Thank You

Accepted Answer

```
$rex = '/^[a-zA-Z][a-zA-Z ]*$/';
```

Or

```
$rex = '/^[a-z][a-z ]*$/i'; // i means case insensitive
```

Solution