Check if a string has a particular format?

Question

I need a `boolean` to check if a given string follows the below format: x.x.x or 1.2.3 , where x is a single digit ``` if string format == x.x.x then TRUE. if string format != x.x.x then FALSE. ``` How can I achieve this?

Accepted Answer

You can try using this regex:

```
String x = "9.8.7";
boolean matches = x.matches("\d\.\d\.\d"); // true
```

Notice that the dot `.` is being escaped `\.`, because it has a special meaning in regex.

Here some input/output samples:

```
"99.8.7"   -> false
"9.9.7."   -> false
"9.97"     -> false
```

Check if a string has a particular format?

Solution

Problem