PHP - regex to reformat JSON

Question

Hi,

I've been trying to figure out how to reformat multiple JSON files into a single one using php, but am having a difficult time understanding how to use complex regular expressions. Suppose I hade multiple instances of the following JSON data:

{
    "felines": {
        "cats": [
            {
                "age": 7,
                "name": "frank" 
            },
            {
                "age": 4,
                "name": "popeye" 
            } 
        ] 
    },
    "canines": {
        "dogs": [
            {
                "age": 2,
                "name": "lucy" 
            },
            {
                "age": 12,
                "name": "wilson" 
            } 
        ] 
    }
}

Lets say I had 2 instances of this JSON object in a php script, and wanted to create a single JSON object that combined both "feline" objects from the two separate JSON instances I had, removing the "canines" objects. The file I'd ultimately want would look like this:

{
    "felines": {
        "cats": [
            {
                "age": 7,
                "name": "frank" 
            },
            {
                "age": 4,
                "name": "popeye" 
            } 
        ] 
    },
    "felines": {
        "cats": [
            {
                "age": 6,
                "name": "sam" 
            },
            {
                "age": 4,
                "name": "kelly" 
            } 
        ] 
    }
}

Does anyone know how i might be able splice and combine these JSON objects with regular expressions using php?

Thanks.

Answer 1

I doubt this is a problem you should try to solve with regexes. Consider converting the JSON files to associative arrays, do your merging, and then change back to JSON.

Answer 2

why don't you use json_encode & json_decode to do the works on php arrays seems to be a lot more easy then doing that with regular expressions.

Answer 3

Regular expressions are, in general, really bad at dealing with arbitrarily nested contexts like JSON data, HTML tags, programming languages, etc. Some extended regular expression libraries patch around those deficiencies.

But, really, is there a reason you need to do this in JSON itself? And with regex? You're probably going to have a much easier time deserializing the data to real PHP data structures, and merging/manipulating things there. Then, when you're done, re-serialize the result.

Answer 4

The best way to do it would be as RageZ suggested, using json_encode and json_decode, however JSON doesn't allow you to have the same key name, does it? The best you can get would be this:

{
 "felines": {
  "cats": [
   {
    "age": 7,
    "name": "frank"
   },
   {
    "age": 4,
    "name": "popeye"
   },
   {
    "age": 6,
    "name": "sam"
   },
   {
    "age": 4,
    "name": "kelly"
   }
  ]
 }
}