Check and validate the phone number and replace if it's in the wrong format

Question

I want to validate the phone number field and it should accept the valid phone number entries only.

e.g:

1. if I enter phone number as 337485552599 it should automatically replace the phone number as 07485552599

2. if I enter phone number as 00337485552599 it should automatically replace the phone number as 07485552599

Answer 1

The best way to do this is using a trigger, but there are several considerations based on the problem you've described...

Validation

If you know exactly how many digits all your phone numbers will be then this isn't a problem, you simply need to check for the right number of characters, but I know of several countries (France included, which by the +33 dialling code is where I am guessing you are from) whose phone numbers can have a varying number of digits. In the UK, both 9 and 10 digit (excluding prefixes) are valid, which means unless you are checking against a database you may run into some problems.

Replacement

Replacing parts of the phone number sting is trivial as long as you know exactly which characters to replace, but as described above if the number is not n digits long, you will have some issues.

Solution

If you just want the two particular cases you gave in your question to be covered, the following code will suffice:

trigger PhoneReplace on Account (before insert) {

    for (Account a : trigger.New) {

        if (!String.IsBlank(a.Phone)) {
            if (a.Phone.startsWith('0033')) {
                a.Phone = '0' + a.Phone.right(a.Phone.length() - 4);
            } else if (a.Phone.startsWith('33')) {
                a.Phone = '0' + a.Phone.right(a.Phone.length() - 2);
            } 
        }

    }

}