Degrees, Minutes and seconds regex

Question

I need validate with RegEx an sexagecimal value, for example: 24° 12' 55,4" or 32° 24' 15,4". For now, I have the next RegEx, that matches successful with degrees and minutes: ``` ^([0-8][0-9]|[9][0])°\s([0-4][0-9]|[5][9])'$ ``` But, when add the seconds validator have problems: ``` ^([0-8][0-9]|[9][0])°\s([0-4][0-9]|[5][9])'\s([0-4][0-9]|[5][9],[0-9])''$ ``` I'm new with RegEx, any ideas?

Accepted Answer

First off, you have some redundancy:

```
^([0-8][0-9]|[9][0])°\s([0-4][0-9]|[5][9])'$
```

can become just:

```
^([0-8][0-9]|90)°\s([0-4][0-9]|59)'$
```

Next you have a logical issue, in your second match, you're matching 0-4 then 0-9 (ie 00-49) and then matching just 59. You can change this to:

```
^([0-8][0-9]|90)°\s[0-5][0-9]'$
```

to match 00-59

Next let's look at your seconds modification:

```
\s([0-4][0-9]|[5][9],[0-9])''$
```

Same issue as before, except now you've added a decimal, but not to both sides of the | so it will only match on one side, if we fix this like we fixed the last one we get:

```
^([0-8][0-9]|90)°\s[0-5][0-9]'\s[0-5][0-9],[0-9]''$
```

Next you have two single quotes instead of a double quote, so fix that:

```
^([0-8][0-9]|90)°\s([0-5][0-9])'\s[0-5][0-9],[0-9]"$
```

Now we need to ask ourselves, is the first digit on this mandatory? Probably not. So mark it as potentially missing using a `?`

```
^([0-8]?[0-9]|90)°\s[0-5]?[0-9]'\s[0-5]?[0-9],[0-9]"$
```

Next, is the fractional part of the second mandatory? Probably not, so mark it as potentially missing:

```
^([0-8]?[0-9]|90)°\s[0-5]?[0-9]'\s[0-5]?[0-9](,[0-9])?"$
```

Finally, I'm assuming that each part except for the degrees is not required, mark them as potentially missing:

```
^([0-8]?[0-9]|90)°(\s[0-5]?[0-9]')?(\s[0-5]?[0-9](,[0-9])?")?$
```

There's other things you can do to make this better. But, this should get you started.

Degrees, Minutes and seconds regex

Solution

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