正则表达式：将重复的组与不重复的组进行匹配

Question

I have a Json string that I need to extract some data from using Regex in C# The string is something like this:

{
  "key1": "value1",
  "key2": "value2",
  "key3": "value3",
  "key4": [
    {
      "arrayKey1": 1,
      "arrayKey2": "something",
      "arrayKey3": "somethingelse"
    },
   {
      "arrayKey1": 2,
      "arrayKey2": "something2",
      "arrayKey3": "somethingelse2"
    },
   {
      "arrayKey1": 3,
      "arrayKey2": "something3",
      "arrayKey3": "somethingelse3"
    }
  ],
  "some very long text here": ""
  "anotherKey": "value",
  "keylast": "valuelast"
}

I want to extract the array's values with named groups, I did it with the following regex: (?:"arrayKey1": (?<arrayKey1>[^"]+),[\\n\\t ]+"arrayKey2": "(?<arrayKey2>[^"]+)",[\\n\\t ]+"arrayKey3": "(?<arrayKey3>[^"]+)")

This works great and I get each match for each item of the array with 3 groups of each key.

Now I want to add an extra match that will contain only the value of "anotherKey" I can't get to work, Here are some regexs I have tried but didn't work:

(?:"arrayKey1": (?<arrayKey1>[^"]+),[\n\t ]+"arrayKey2": "(?<arrayKey2>[^"]+)",[\n\t ]+"arrayKey3": "(?<arrayKey3>[^"]+)")(?:[\s\S]*)(?:"anotherKey": "(?<anotherKey>[^"]+)")

This one does get the "anotherKey", but it only returns the first item in the array, not all of them.

Also: https://regex101.com/r/mfXlRs/1

Can someone put me in the right way?

Thanks

Answer 1

Your regex for arrayKey1..3 (only) gave three separate matches, and in each match you got the 3 required values.

Now, after you added the fragment looking for anotherKey , but at the parent level, the situation changed. Now you have only a single match, because:

• Your "old" regex matches only the first set of arraykeys .
• Then (?:[\\s\\S]*) matches everything up to anotherKey , including both remaining sets of arraykeys .
• The added part matches just anotherKey .

Maybe you should perform your matching in 2 separate steps:

• Start from the first (old) match, getting 3 matches for arraykeys and store them somewhere.
• Then run the second match, only for anotherKey .

Adding + quantifier to the "old" group will not help, because if a capturing group was matched several times, then the group would hold only the last match.