Regex to determine if a string starts with more than one capital letter

Question

I am trying to determine if a string has more than 1 capital letter in a row at the start of a string. I have the following regex but it doesn't work:

`^[A-Z]{2,1000}`

I want it to return true for:

• ABC
• ABc
• ABC ABC
• ABc Abc

But false for:

• Abc
• AbC
• Abc Abc
• Abc ABc

I have the 1000 just because I know the value won't be more than 1000 characters, but I don't care about restricting the length.

I am working with PHP, if it makes any difference.

Answer 1

Wouldn't leaving the second one do it?

^[A-Z]{2,}

Which basically says "string starts with 2 or more capital letters"

Here's some tests with the strings you provided that should match:

>>> 'ABC'.match(/^[A-Z]{2,}/);
["ABC"]
>>> 'ABc'.match(/^[A-Z]{2,}/);
["AB"]
>>> 'ABC ABC'.match(/^[A-Z]{2,}/);
["ABC"]
>>> 'ABc Abc'.match(/^[A-Z]{2,}/);
["AB"]

And then the ones it shouldn't match for:

>>> 'Abc'.match(/^[A-Z]{2,}/);
null
>>> 'AbC'.match(/^[A-Z]{2,}/);
null
>>> 'Abc Abc'.match(/^[A-Z]{2,}/);
null
>>> 'Abc ABc'.match(/^[A-Z]{2,}/);
null

If you only want to match the first two, you can just do {2}

Answer 2

Try ^[A-Z][A-Z]

Answer 3

So do you want it to match the entire line if the first 2 letters are capital? If so, this should do it...

^[A-Z]{2,}.*$

Answer 4

php > echo preg_match("/^[A-Z]{2}/", "ABc");
1
php > echo preg_match("/^[A-Z]{2}/", "Abc");
0

/^[A-Z]{2}/ seems to work for me. Since you're doing a substring match anyways, there's no need to do {2,} or {2,1000}.

Answer 5

I ran ^[A-Z]{2,} through the Regex Tester for egrep searches, and your test cases worked.

Answer 6

Since your regex works fine at finding which line begins with 2 caps, i assume you had another question.

Maybe you have case insensitve on

Try

(?-i)^[A-Z]{2,}

Or maybe you meant "match the whole line"

(?-i)^[A-Z].*$

Answer 7

non regex version

$str="Abccc";
$ch = substr($str,0,2);
if ( $ch == strtoupper($ch) ){
    print "ok";
}else{
    print "not ok";
}