C# newtonsoft.json get MAX ID

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How to get max ID from json (Array) fromat below:

[
  {
    "Group": "1",
    "ID": 1,
    "Name": "User1",
    "Description": "Desc1"
  },
  {
    "Group": "2",
    "ID": 3,
    "Name": "User2",
    "Description": "Desc2"
  },
  {
    "Group": "3",
    "ID": 2,
    "Name": "User3",
    "Description": "Desc3"
  }
]

Also json (Object) format:

{
  "Group": "1",
  "ID": 1,
  "Name": "User1",
  "Description": "Desc1"
},
{
  "Group": "2",
  "ID": 3,
  "Name": "User2",
  "Description": "Desc2"
},
{
  "Group": "3",
  "ID": 2,
  "Name": "User3",
  "Description": "Desc3"
}

Desired output:

What I have tried:

Many of them available for JavaScript code, Looking for C#
eg: Edit fiddle - JSFiddle - Code Playground[^]

Posted 5-Nov-21 22:02pm

DevJr

Updated 6-Nov-21 3:49am

v5

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2 solutions

Solution 1

The way you do it is not to manipulate the JSON directly: you read the JSON data into C~ objects - that's what Newtonsoft is there for - manipulate the C# objects, then cretae your summary data from that.

Manipulating the JSON directly is a PITA because it's text based and there are no "fixed points" to work from, including rows or even lines!

Posted 5-Nov-21 22:47pm

OriginalGriff

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This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

DevJr · Accepted Answer · 2021-11-06T03:34:00

Hmmm... got it! this works for json that begin with [,
i think for some tweaks, this will also works for the json that begin with {

public int GetMaxIDLINQ()
{
  var userLists = JsonConvert.DeserializeObject<List<Author>>(json);
  int maxID = userLists.Max(x => x.ID);

  Console.WriteLine("Max ID :" + maxID.ToString());
  return maxID;
}

Or:

public int GetMaxID()
  {
    int maxID = JsonConvert.DeserializeObject<List<UserRoot>>(json)
                .Select(s => s.ID)
                .Max();

    Console.WriteLine("Max ID :" + maxID.ToString());
    return maxID;
  }

Also:

public int GetMaxID()
  {
    var userLists = JsonConvert.DeserializeObject<List<UserRoot>>(json);
    var maxID = userLists.OrderByDescending(i => i.ID).FirstOrDefault();

    Console.WriteLine("Max ID :" + maxID.ID.ToString());
    return maxID.ID;
  }

Hope that helps someone :)

C# newtonsoft.json get MAX ID

2 solutions

Solution 1

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C# newtonsoft.json get MAX ID

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