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how to iterate through json array

How do we iterate through the Map array?
My payload looks like this:
{
"Record": "...bunch of hl7 data...",
"Map": [{ "DG1.2": "PatientDiag1" }, { "DG1.3": "PatientDiag2" }]
}
How do we iterate and parse the values of the Map array?
I've tried the following:
var blobObject = JObject.Parse(blob);
var map = blobObject["Map"]; //it's a JToken at this point
//now let's parse each key/value pair in the map:
foreach (var field in map)
{
var key = field.ToString();
var value = field[0].Value
}

"Map" is an array of JSON objects, so first you need to loop through the array, then you can loop through the key/value pairs of each object:
var blobObject = JObject.Parse(blob);
var map = blobObject["Map"]; //it's a JToken at this point
//now let's parse each key/value pair in the map:
foreach (var item in map.Cast<JObject>()) // Map is an array of objects so loop through the array, then loop through the key/value pairs of each object
{
foreach (var pair in item)
{
var key = pair.Key;
var value = pair.Value;
}
}
Or if you prefer to flatten the array with LINQ's SelectMany():
foreach (var pair in map.SelectMany(o => (IDictionary<string, JToken>)o))
{
var key = pair.Key;
var value = pair.Value;
}
Notes:
From the JSON spec
JSON is built on two structures:
A collection of name/value pairs. In various languages, this is realized as an object, record, struct, dictionary, hash table, keyed list, or associative array.
An ordered list of values. In most languages, this is realized as an array, vector, list, or sequence.
A JSON array is mapped to a JArray while a JSON object is mapped to a JObject.
How do we ... parse the values of the Map array? You don't need to parse the values of the Map array, they are already fully parsed. You just need to query them with LINQ to JSON.
Demo fiddle here.

var blobObject = JObject.Parse(blob);
var map = blobObject["Map"];
var values = map.Values().OfType<JProperty>();
foreach (JProperty prop in values)
{
Console.WriteLine(prop.Name); // property name
Console.WriteLine(prop.Value);// property value
}
Get all the values from Map key as JProperty, then loop through each property and you can access the property name using prop.Name and the value using prop.Value.

Converting multiple JSON arrays

I have been kindly provided with the code below to convert a JSON array to a single object. I would like to use the same code to change multiple properties. All arrays will have a single object.
I would like to add some code that will walk through the JSON and execute the code below on any properties that have been found. Most properties are nested, hence the need to walk through the JSON.
// Load the JSON from a file into a JObject
JObject o1 = JObject.Parse(File.ReadAllText(#"output.json"));
// Get the desired property whose value is to be replaced
var prop = o1.Property("to_Description");
// Replace the property value with the first child JObject of the existing value
prop.Value = prop.Value.Children<JObject>().FirstOrDefault();
// write the changed JSON back to the original file
File.WriteAllText(#"output.json", o1.ToString());

Replace the middle two lines with these:
// Find all properties anywhere in the JSON whose values are arrays
var arrayProperties = o1.Descendants()
.OfType<JProperty>()
.Where(p => p.Value.Type == JTokenType.Array);
foreach (JProperty prop in arrayProperties)
{
// Replace the property value with the first child JObject of the existing value
prop.Value = prop.Value.Children<JObject>().FirstOrDefault();
}
Fiddle: https://dotnetfiddle.net/iP8Ibd

How to convert the following JSON array into IDictionary<string, object>?

Following is the serialized JSON array I want to convert to IDictionary
[
{
"8475": 25532
},
{
"243": 521
},
{
"3778": 15891
},
{
"3733": 15713
}
]
When I tried to use
JsonConvert.DeserializeObject<IDictionary<string, object>>((string)jarray);
I got an error saying:
Cannot cast 'jarray' (which has an actual type of 'Newtonsoft.Json.Linq.JArray') to 'string'
The JSON deserializer requires only a string.

If you already have the JArray, all you have to do is convert it to a dictionary I guess.
Roughly something like this:
IDictionary<string,object> dict = jarray.ToDictionary(k=>((JObject)k).Properties().First().Name, v=> v.Values().First().Value<object>());
Check this for complete code with an example
I think there might be a better way to convert it to a dictionary though. I'll keep looking.

the JsonConvert.DeserializeObject<T> Method takes a JSON string, in other words a serialized object.
You have a deserialized object, so you'll have to serialize it first, which is actually pointless, considering you have all the information you need right there in the JArray object. If you are aiming just to get the objects from the array as key value pairs, you can do something like this:
Dictionary<string, object> myDictionary = new Dictionary<string, object>();
foreach (JObject content in jarray.Children<JObject>())
{
foreach (JProperty prop in content.Properties())
{
myDictionary.Add(prop.Name, prop.Value);
}
}

To turn your JArray into a string, you'll need to assign the key & values of the dictionary for each element. Mario gave a very accurate approach. But there's a somewhat prettier approach as long as you know how to convert each item into your desired type. The below example is for Dictionary<string, string> but can be applied to any Value type.
//Dictionary<string, string>
var dict = jArray.First() //First() is only necessary if embedded in a json object
.Cast<JProperty>()
.ToDictionary(item => item.Name,
item => item.Value.ToString()); //can be modified for your desired type

Add element to a tuple outside of initialization c#

I'm new to programming, and I created a tuple list with
var tupleList = new List<Tuple<string, string>> { };
Later on in the code, I'd like to add an element like
tupleList.Add(string1,string2);
but .Add doesn't support this somehow?
Basically, I'm going through a loop and adding to the tuple and later I want to search through the tuple for a sample string, so my second question is how would I search through tupleList.Item1 and get all the pairs that equal, for example string10? I saw an answer for dictionary values, but can I do the same for tuples?
var matches = tupleList.Where(pair => pair.Item1.Equals(string10))
.Select(pair => Item2.Key);
I don't know if that makes sense though, this was the original code:
var matches = dict.Where(pair => pair.Value == "abc")
.Select(pair => pair.Key);

List<T> does not have any specific methods for working with tuples. It works with any type T. If you want to add new item to list, you should create item of list's type T and pass it to list. Adding new tuple:
tupleList.Add(Tuple.Create(string1,string2));
For searching just filter tuples list. You should not project tuples with Select operator if you want to get them as result:
var matches = tupleList.Where(pair => pair.Item1 == string10);
NOTE: I don't like tuples for their meaningless names Item1, Item2 etc, which is hard to understand. Consider creating custom class which will have properties with descriptive names.

I'd say why do the same for tuples?
If you are using a tuple to represent a key value pair, just stick to a key value pair, which is what a dictionary contains a collection of. If you model a row with more than 2 values, I'd probably favour a strongly typed model over this, where you can be more explicit in your LINQ queries.

c# associative array with dictionary

I want to build an Dictonary like this :
Dictionary<String, ArrayList> myDic = new Dictionary<String, ArrayList>();
in the end i want a structure like :
["blabla"] => array(1,2,3)
["foo"] => array(1,4,6,8)
.......
to build this i run in a loop and in every loop build some strings ,
first question :
how to check every time if this string exists
in the dictionary , if its not exists open a new entry in dictionary with one element in the array list, if exists only add another element to the array list
and another question:
how can i sort this dictionary according to number of elements in the array list(In descending order) like :
["foo"] => array(1,4,6,2,8)
["bar"] => array(4,6,2,8)
["bla"] => array(1,2,3)
["blo"] => array(1,2)
.......
thanks !

Use the right tool for the job. The data structure you want is called a "multi-dictionary" - that is a dictionary that maps from a key to a sequence of values, rather than from a key to a unique value.
The PowerCollections codebase contains an implementation of MultiDictionary that probably does what you want. I would use it rather than writing your own.
To sort the dictionary into a sequence of key/sequence pairs ordered by the length of the sequence, I would use a LINQ query with an "order by" clause. That seems like the easiest way to do it.

Instead of ArrayList you should use an array or List<T>. Assuming you have a Dictionary<string, int> called source this should work:
var items = source
.GroupBy(kvp => kvp.Key)
.Select(grp => new { Key = grp.Key, Items = grp.Select(kvp => kvp.Value).ToArray() })
.OrderByDescending(i => i.Items.Length);
To explain, Dictionary<TKey, TValue> implements IEnumerable<KeyValuePair<TKey, TValue>> so can be considered a sequence of key-value pairs. Group by groups the pairs by key and then Select creates a sequence of an anonymous type which contains the key and associated values in a Key and Items property respectively. This sequence is then ordered by the number of items in the Items array of each object.
If you want to order them by the length of the created array, you can't use a dictionary since they are not ordered.

To check if a key exists in a dictionary and use the value if it does, you can use TryGetValue:
ArrayList array;
if(!myDic.TryGetValue("blabla", out array))
{
array = new ArrayList();
myDic["blabla"] = array;
}
array.Add(42);

Would something like this work:
if (myDic.ContainsKey(myString))
myDic[myString].Add(myNumber);
else
myDic.Add(myString, new ArrayList(new int[] {myNumber}));