phpregexpreg-replacecamelcasingkebab-case

Replace matched uppercase letter with its lowercase version (camelCase to kebab-case)

I'm trying to make a preg_replace() pattern to convert the text "orderId" into "order-id".

$argumentName = "orderId";
$argumentName = preg_replace("/([A-Z])/e", "-strtolower($1)", $argumentName);
echo $argumentName;

The output for this line is "order0d". Why is this not working?

Solution

  • Since you're specifying that your replacement-string is an expression, this:

    strtolower($1)

    is 'i' (as it should be), and this:

    -strtolower($1)

    is -'i' ("negative 'i'"), which forces the string 'i' to be interpreted as a number — 0.

    What you want is

    $argumentName = preg_replace("/([A-Z])/e", "'-' . strtolower($1)", $argumentName);

    which concatenates the strings '-' and 'i'.