除了括号中显示的逗号外，如何分割逗号？

Question

I want to split like this:

Before:

TEST_A, TEST_B, TEST_C (with A, B, C), TEST_D

After:

TEST_A
TEST_B
TEST_C (with A, B, C)
TEST_D

How can I split it?

Answer 1

Regex isn’t going to help this time, so you will have to iterate through the characters.

Fact is, regular expressions aren’t very context-aware. For that reason, you can’t use regular expression to parse HTML. This is why we’re better off iterating through the string ourselves.

function magic_split($str) {
    $sets = array('');  // Sets of strings
    $set_index = 0;     // Remember what index we’re writing to
    $brackets_depth = 0; // Keep track if we’re in brackets (or not)

    // Iterate through entire string
    for($i = 0; $i < strlen($str); $i++) {
        // Skip commas if we’re not in brackets
        if($brackets_depth < 1 && $str[$i] === ',') continue;

        // Add character to current list
        $sets[$set_index] .= $str[$i];

        // Store brackets depth
        if($str[$i] === '(') $brackets_depth++;
        if($str[$i] === ')') $brackets_depth--;

        if(
            $i < strlen($str) - 1 && // Is a next char available?
            $str[$i+1] === ',' &&   // Is it a comma?
            $brackets_depth === 0   // Are we not in brackets?
        ) $sets[++$set_index] = '';  // Add new set
    }

    return $sets;
}

$input = 'TEST_A, TEST_B, TEST_C (with A, B, C), TEST_D';
$split = magic_split($input);