Weird whitespace error in PHP - php

Question

I have phone numbers that I want to format
And I have a pattern matcher that breaks down the numbers into a 10 digit format, and then applies dashes.
It works most of the time. However Im having an issue with certain numbers.
$trimmed = trim(preg_replace('/\s+/', '', $v->cust_num));
$tendigit = str_replace(array( '(', ')','-',' ' ), '', $trimmed);
$num = substr($tendigit,0,3)."-".substr($tendigit,3,3)."-".substr($tendigit,6,4);
This will change [phone], or 555-555 5555 or 5555555555 or (555)-555-5555 or 555-555-5555
to my format of 555-555-5555
However, I came across a few entries in my database, that dont seem to want to change.
One of the bad entries is this one. It contains two white spaces infront of the 4.
4-035-0100
When it runs through $trimmed, and I output $tendigit...it outputs
40350100
as expected. But then when I apply $num to it. It goes back to
4-035-0100
I would at least expect it to be
403-501-00
It seems there is some hidden whitespace in it, that my preg_replace, trim, and str_replace are not attacking.
Any ideas??
Thanks

Answer 1

The code below works, I have tried it with the special characters we discovered in the comments. Basically, the regex removes everything that isnt a number (0-9) and then uses your original formatting.
$trimmed = preg_replace('/\D+/', '', $v->cust_num);
$num = substr($trimmed,0,3)."-".substr($trimmed,3,3)."-".substr($trimmed,6,4);

Answer 2

You can condense your code a little:
$tendigit = preg_replace('/[^\d]/', '', $v->cust_num);
$num = substr($tendigit,0,3)."-".substr($tendigit,3,3)."-".substr($tendigit,6,4);
Though, you should add in some conditions to check that the phone number actually has 10 digits too:
$tendigit = preg_replace('/[^\d]/', '', $v->cust_num);
if(strlen($tendigit == 10)){
$num = substr($tendigit,0,3)."-".substr($tendigit,3,3)."-".substr($tendigit,6,4);
} else {
// catch your error here, eg 'please enter 10 digits'
}
The first line removes any 'non-digit' [^\d].
The conditional statement checks if the $tendigit variable has 10 digits in it.
If it does, then it uses your code to parse and format.
If it doesnt, then you can catch an error.