Split words in a camelCased string before each uppercase letter

Question

I have strings like:

$a = 'helloMister';
$b = 'doggyWaltz';
$c = 'bumWipe';
$d = 'pinkNips';

How can I explode at the capital letters?

Humbertohumble

Answer 1

If you want to split helloMister into hello and Mister you can use preg_split to split the string at a point just before the uppercase letter by using positive lookahead assertion:

$pieces = preg_split('/(?=[A-Z])/',$str);

and if you want to split it as hello and ister you can do:

$pieces = preg_split('/[A-Z]/',$str);

Deerdre

if first character is already uppercase this regex generates one empty element, if you want to ommit that you can use lcfirst first: $pieces = preg_split('/.(?=[A-Z])/',lcfirst($str)); – Spermatid

This is work fine if the first character is a lowercase, but Suppose we need to explode RecipesActionModel and we want only array of three elements Receipe,Action,Model. This solution make array with four elements which element 0 is empty. – Multiplicand

Thank you so much for this, I was researching positive lookahead assertion, and your answer helps me out a lot! – Boulanger

Wrap it with array_filter to get rid of any empty element. – Binkley

Use this to avoid first empty element in case first element is upper case. preg_split('/(?=[A-Z])/', 'CamelCase', -1, PREG_SPLIT_NO_EMPTY); – Horrific

Answer 2

Look up preg_split

$result = preg_replace("([A-Z])", " $0", "helloMister");
print_r(explode(' ', $result));

hacky hack. Just don't have spaces in your input string.

Millinery

The parentheses are misleading at first glance and should not be used as delimiters (even if they are valid). – Illiterate

Answer 3

Extending Mathew's Answer, this works perfectly,

$arr = preg_replace("([A-Z])", " $0", $str);
$arr = explode(" ",trim($arr));

Telepathist

Answer 4

Further on the selected answer.

If you are dealing with acronyms in the text, it will change OOP to O O P

You can then use preg_split('/(?=[A-Z][a-z])/', $text) to lookahead for the lower case too to capture words fully.

Mika

Answer 5

Look at preg_split, it's like explode but takes a regular expression

preg_split('~[A-Z]~',$inputString)

Butte

I was thinking the same thing, I assume they also want the capital letter as part of the 2nd word. – Millinery

Cool this is nice, does this output an array? – Humbertohumble