Replacing ',' characters in only odd positions - php

Question

I need replace ',' characters with regex in php, but only in odd positions
I have:
{"phone","11975365654","name","John Doe","cpf","42076792864"}
I want replace ',' to ':', but only the odd:
{"phone":"11975365654","name":"John Doe","cpf":"42076792864"}
I'm trying this regex:
preg_replace('/,/', ':', $data)
But it get all quotes and no only the odd.
Can you help me?

Answer 1

Make it simple:
preg_replace('/(("[a-z]+"),(".+?"))+/', '$2:$3', $a)

Answer 2

Rather than regex, this just converts the list to an array (using str_getcsv() to cope with the quotes). Then loops every other item in the list, using that item as the key and the next item as the value. This can then be json_encoded() to give the result...
$data = str_getcsv(trim($input, "{}"));
$output = [];
for ( $i=0, $k=count($data); $i < $k; $i+=2) {
$output[$data[$i]] = $data[$i+1];
}
echo json_encode($output);

Answer 3

It is not ideal to use regex for this task. Having said that, if you know that your input can be matched by a simple regex, this should do it :
$str = '{"phone","11975365654","name","John Doe","cpf","42076792864"}';
$result = preg_replace('/,(.*?(?:,|[^,]*$))/ms', ':\\1', $str);
This lenient to some extra characters but it will fail if any string contains commas
Example

Answer 4

Here's an example of using standard PHP functions:
$input = '{"phone","11975365654","name","John Doe","cpf","42076792864"}';
$dataIn = str_getcsv(trim($input, '{}'));
$keys = array_filter($dataIn, function ($key) { return !($key & 1); }, ARRAY_FILTER_USE_KEY);
$values = array_filter($dataIn, function ($key) { return $key & 1; }, ARRAY_FILTER_USE_KEY);
$DataOut = array_combine($keys, $values);
$output = json_encode($DataOut);
echo $output;
This code is a lot longer than using a regex, but it is probably easier to read and maintain in the long run. It can cope with commas in the values.

Answer 5

Another option could be using array_splice and loop while there are still elements in the array:
$str = '{"phone","11975365654","name","John Doe","cpf","42076792864"}';
$data = str_getcsv(trim($str, '{}'));
$result = array();
while(count($data)) {
list($k, $v) = array_splice($data, 0, 2);
$result[$k] = $v;
}
echo json_encode($result);
Output
{"phone":"11975365654","name":"John Doe","cpf":"42076792864"}