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JSON extract date from matching string

I am entirely new to JSON, and haven't got any familiarity with it at all. I'm tinkering around with some JSON data extracts to get a feel for it.
Currently, I have a chat export which has a large number of keys. Within these keys are a "date" key, and a "from_id" key.
I would like to search a JSON file for a matching value on the "from_id" key, and return all the values against the "date" keys with a matching "from_id" value.
For example:
{
"name": "FooBar Chat Group",
"type": "textchat",
"id": 123456789,
"messages": [
{
{
"id": 252930,
"type": "message",
"date": "2021-03-03T01:39:30",
"date_unixtime": "1614735570",
"from": "Person1",
"from_id": "user1234",
"text": "This is a message!"
},
{
"id": 252931,
"type": "message",
"date": "2021-03-03T01:41:03",
"date_unixtime": "1614735663",
"from": "Person2",
"from_id": "user9876",
"text": "This is a reply!"
},
{
"id": 252932,
"type": "message",
"date": "2021-03-03T01:42:01",
"date_unixtime": "1614735721",
"from": "Person2",
"from_id": "user9876",
"text": "This is some other text!"
},
{
"id": 252933,
"type": "message",
"date": "2021-03-03T01:42:44",
"date_unixtime": "1614735764",
"from": "Person1",
"from_id": "user1234",
"text": "Yeah, indeed it is!"
}
]
}
I want to search from_id "user1234", and for it to return the following:
2021-03-03T01:39:30
2021-03-03T01:42:44
These are the two dates that have a matching from_id.
How would I go about doing something like this, please?
I am entirely new to this, so a super basic explanation with resources would really be appreciated. Thanks!

you can try this c# code. At first you have to parse your json strig to create an object from string. Then you can use LINQ to get the data you need
using Newtonsoft.Json;
JArray messages = (JArray) JObject.Parse(json)["messages"];
string from_id="user1234";
DateTime[] dates = messages
.Where(m=> (string) m["from_id"] ==from_id)
.Select(m => (DateTime) m["date"])
.ToArray();

Assuming your sample is part of a JSON Array - starts with [ and ends with ] - you should be able to iterate and conditionally select what you want.
In javascript, you can use a for of to iterate through and an if to match your request:
for(let item of array){
if(item['from_id'] == 'user1234')
console.log(item.date);
}
As we don't know the language you're actually using, a more wide code version of it could be something like:
for(let i=0;i < array.length; i++){
if(array[i]['from_id'] == 'user1234'){
print(array[i]['date']);
}
}

Transform a JSON object to a JSON array, taking the first level of properties

I've this JSON object
{
"08f4f705-6e14-4781-8241-d04bf2dc6ada": {
"description": "xxxxxxxx",
"note": "yyyyyyyy"
},
"05f4f995-6e14-4567-8241-d04bf2d456ee": {
"description": "aaaaaa",
"note": "bbb"
},
"0675f995-6e14-4567-8241-d4567f2d456z": {
"description": "fffff",
"note": "gggg"
}
}
I need to convert into a JSON array like this:
(the elements should be the content of the first level properties)
[
{
"description": "xxxxxxxx",
"note": "yyyyyyyy"
},
{
"description": "aaaaaa",
"note": "bbb"
},
{
"description": "fffff",
"note": "gggg"
}
]
I can't manipulate the object and I didn't find an appropriate resource to follow. How can I do it?

You can achieve this by deserializing your json string into Dictionary<string, object>:
var obj = JsonConvert.DeserializeObject<Dictionary<string, object>>(json);
After that you extract the values and serialize them back to json:
var newJson = JsonConvert.SerializeObject(obj.Values);

How do i deserialize this dictionary<string,string[]>

I have the following json :
[
{
"Key": "tradepack",
"Value": [
"Select Tradepack"
]
},
{
"Key": "route",
"Value": [
"Select Route"
]
},
{
"Key": "recall",
"Value": [
"Select Recall Location"
]
},
{
"Key": "stones",
"Value": [
"True"
]
},
{
"Key": "quickstep",
"Value": [
"True"
]
},
{
"Key": "dreamingdonkey",
"Value": [
"True"
]
},
{
"Key": "meleeskills",
"Value": []
},
{
"Key": "rangedskills",
"Value": []
},
{
"Key": "buffedskills",
"Value": []
}
]
Im currently using this
String data = System.IO.File.ReadAllText(Application.StartupPath + "\\folder\\Data\\Config\\config.txt");
return JsonConvert.DeserializeObject<Dictionary<string, object[]>>(data);
but i get the following error
Cannot deserialize the current JSON array (e.g. [1,2,3]) into type 'System.Collections.Generic.Dictionary`2[System.String,System.Object[]]' because the type requires a JSON object (e.g. {"name":"value"}) to deserialize correctly.
To fix this error either change the JSON to a JSON object (e.g. {"name":"value"}) or change the deserialized type to an array or a type that implements a collection interface (e.g. ICollection, IList) like List that can be deserialized from a JSON array. JsonArrayAttribute can also be added to the type to force it to deserialize from a JSON array.
Path '', line 1, position 1.
Anyone care to explain as how i would solve this im a newb in c# especially serialization

Your json is an array/list. So you need to deserialize to something like this List<Dictionary<string, object>>
var data = JsonConvert.DeserializeObject<List<Dictionary<string, object>>>(json);
OR
var dict = JArray.Parse(json)
.Select(x => x.ToObject<KeyValuePair<string, string[]>>())
.ToDictionary(x => x.Key, x => x.Value);

Your data looks more like a KeyValuePair<string, string[]>[]. You can try deserializing to that, then creating a dictionary based on the result.
var kvps = JsonConvert.DeserializeObject<KeyValuePair<String, String[]>[]>(data);
return kvps.ToDictionary((keyItem) => keyItem.Key, (valueItem) => valueItem.Value);

Deserialize Dynamic Json string using Newtonsoft JSON.NET

I have a JSON string that I'm getting from Facebook API, in which I have a node whose name changes according to its content, for example some time it is 45, or 58 etc.
It could be any number.
I want its value. How to get it?
Example:
{
"data": [
{
"id": "1492292372_10201810786059989",
"created_time": "2014-04-05T09:00:54+0000"
},
{
"id": "1492292372_10201804679827337",
"created_time": "2014-04-04T07:29:07+0000"
},
{
"id": "1492292372_10201804649306574",
"created_time": "2014-04-04T07:10:33+0000"
},
{
"id": "1492292372_10201801316823264",
"created_time": "2014-04-03T18:31:50+0000"
},
{
"id": "1492292372_10201798962284402",
"created_time": "2014-04-03T06:24:47+0000"
},
{
"message_tags": {
"0": [
{
"id": "1492292372",
"name": "Yawar Sohail",
"type": "user",
"offset": 0,
"length": 12
}
],
"15": [
{
"id": "1489845168",
"name": "Zeeshan Anjum",
"type": "user",
"offset": 15,
"length": 13
}
]
},
"id": "1492292372_10201796274777216",
"created_time": "2014-04-02T17:57:05+0000"
},
{
"id": "1492292372_10201794080482360",
"created_time": "2014-04-02T07:26:23+0000"
},
Inside message_tags there are two nodes [0 and 15] they dynamically changes according to their offset values. I want names, type and ids inside these nodes.

You can deserialize your JSON into an ExpandoObject:
var converter = new ExpandoObjectConverter();
dynamic obj = JsonConvert.DeserializeObject<ExpandoObject>(json, converter);
Which dynamically adds members to your object at runtime, and allows you to iterate over them as described in this answer:
foreach (var prop in obj.GetType().GetProperties(BindingFlags.Instance | BindingFlags.Public))
{
Console.WriteLine("Name: {0}, Value: {1}",prop.Name, prop.GetValue(obj,null));
}
That way you can iterate over obj.message_tags to get the individual messages, and obtain all their details respectively.

Parsing JSON in C#

I have a JSON string that I am sending to a c# server. It comprises an array of Event objects and an Array of relationship objects. The relationship objects describe the database table relationships.
However I'm having trouble getting data from the the JSON at the server. The object doesn't exist on the server to deserailize into and JSON.net throws parse errors when I try the following:
// Both throw parse errors
JObject o = JObject.Parse(Request.Form.ToString());
JsonConvert.DeserializeObject<MobileEvents>(Request.Form.ToString());
the JSON:
{
"CreateEvents": {
"Event": [
{
"Id": "1",
"Subject": "Hire a Clown"
}
],
"Relationship": [
{
"Primary": "Table1",
"Secondary": "Table2",
"Field": [
{
"Table1Id": "1",
"Table2Id": [
"101"
]
}
]
},
{
"Primary": "Table1",
"Secondary": "Table3",
"Field": [
{
"Table1Id": "1",
"Table3Id": [
"200025"
]
}
]
},
{
"Primary": "Table1",
"Secondary": "Table4",
"Field": [
{
"Table1Id": "1",
"Table4Id": [
"3"
]
}
]
}
]
}
}

Request.Form.ToString() would returns the result like "a=1&b=3", it's definitely not what you need.
If you're passing values as submiting a form, you can use Request.Form["your-key"] to get the value.
If you're passing values by the http body, you can use new StreamReader(Request.InputStream).ReadToEnd() to get the whole JSON string.

I think you have an error within your getting ...
It's not
this.Request.Form.ToString(); // see http://stackoverflow.com/questions/7065979/why-is-the-return-value-of-request-form-tostring-different-from-the-result-of for output
Instead it should be
this.Request.Form["myInputNAME"].ToString();
Important - really use the name-attribute of your input/select/...-element
Anyways: I would like to encourage you, to use eg. <asp:HiddenField runat="server" ID="foo" />. When you have a server-control you can then access its value by simple doing this.foo.Value at server-side, whereas at client-side you can access the input field like document.getElementById('<%= this.foo.ClientID %>')