Dynamically referring to JSON node in Power Query M - powerbi

I have a function that extracts a node from JSON document as follows:
...
Json = GetJson(Url),
Value = Json[#"values"]
values correspond to the actual node within the JSON document.
I would like to generalize this piece of code and provide the name of the node as a variable like:
let myFunc = (parentNodeName as text) =>
...
Json = GetJson(Url),
Value = Json[parentNodeName]
However getting this error:
An error occurred in the ‘myFunc’ query. Expression.Error: The field 'parentNodeName' of the record wasn't found.
How can I refer to the JSON node dynamically?

Try
(Json, parentNodeName ) =>
let
...
Value = Record.Field(Json,parentNodeName)
in Value
sample code:
let Json = Json.Document(Web.Contents("http://soundcloud.com/oembed?url=http%3A//soundcloud.com/forss/flickermood&format=json")),
Value=myFunc(Json,"title")
in Value
and myFunc:
(Json, parentNodeName ) =>
let
Value = Record.Field(Json,parentNodeName)
in Value

Related

M & Power Query: How to use the $Skip ODATA expression within a loop?

Good afternoon all,
I'm trying to call all of the results within an API that has:
6640 total records
100 records per page
67 pages of results (total records / records per page)
This is an ever growing list so I've used variables to create the above values.
I can obviously use the $Skip ODATA expression to get any one of the 67 pages by adding the expression to the end of the URL like so (which would skip the first 100, therefore returning the 2nd page:
https://psa.pulseway.com/api/servicedesk/tickets/?$Skip=100
What I'm trying to do though is to create a custom function that will loop through each of the 67 calls, changing the $Skip value by an increment of 100 each time.
I thought I'd accomplished the goal with the below code:
let
Token = "Token",
BaseURL = "https://psa.pulseway.com/api/",
Path = "servicedesk/tickets/",
RecordsPerPage = 100,
CountTickets = Json.Document(Web.Contents(BaseURL,[Headers = [Authorization="Bearer " & Token],RelativePath = Path & "count"])),
TotalRecords = CountTickets[TotalRecords],
GetJson = (Url) =>
let Options = [Headers=[ #"Authorization" = "Bearer " & Token ]],
RawData = Web.Contents(Url, Options),
Json = Json.Document(RawData)
in Json,
GetPage = (Index) =>
let Skip = "$Skip=" & Text.From(Index * RecordsPerPage),
URL = BaseURL & Path & "?" & Skip,
Json = GetJson(URL)
in Json,
TotalPages = Number.RoundUp(TotalRecords / RecordsPerPage),
PageIndicies = {0.. TotalPages - 1},
Pages = List.Transform(PageIndicies, each GetPage(_))
in
Pages
I got all happy when it successfully made the 67 API calls and combined the results into a list for me to load in to a Power Query table, however what I'm actually seeing is the first 100 records repeated 67 times.
That tells me that my GetPage custom function which handles the $Skip value isn't changing and is stuck on the first one. To make sure the Skip index was generating them properly I duplicated the query and changed the code to load in the $Skip values and see what they are, expecting them all to be $Skip=0, what I see though is the correct $Skip values as below:
Image showing correct Skip values
It seems everything is working as it should be, only I'm only getting the first page 67 times.
I've made a couple of posts on other community site around this issue before but I realise the problem I was (poorly) describing was far too broad to get any meaningful assistance. I think now I've gotten to the point where I understand what my own code is doing and have really zoomed in to the problem - I just don't know how to fix it when I'm at the final hurdle...
Any help/advice would be massively appreciated. Thank you.
Edit: Updated following #RicardoDiaz answer.
let
// Define base parameters
Filter = "",
Path = "servicedesk/tickets/",
URL = "https://psa.pulseway.com/api/",
Token = "Token",
Limit = "100",
// Build the table based on record start and any filters
GetEntityRaw = (Filter as any, RecordStart as text, Path as text) =>
let
Options = [Headers=[ #"Authorization" = "Bearer " & Token ]],
URLbase = URL & Path & "?bearer=" & Token & "&start=" & RecordStart & "&limit=" & Text.From(Limit),
URLentity = if Filter <> null then URLbase & Filter else URLbase,
Source = Json.Document(Web.Contents(URLentity, Options)),
Result = Source[Result],
toTable = Table.FromList(Result, Splitter.SplitByNothing(), null, null, ExtraValues.Error)
in
toTable,
// Recursively call the build table function
GetEntity = (optional RecordStart as text) as table =>
let
result = GetEntityRaw(Filter, RecordStart, Path),
nextStart = Text.From(Number.From(RecordStart) + Limit),
nextTable = Table.Combine({result, #GetEntity(nextStart)}),
check = try nextTable otherwise result
in
check,
resultTable = GetEntity("0")
in
resultTable
As I couldn't test your code, it's kind of hard to provide you a concrete answer.
Said that, please review the generic code I use to connect to an api and see if you can find where yours is not working
EDIT: Changed api_record_limit type to number (removed the quotation marks)
let
// Define base parameters
api_url_filter = "",
api_entity = "servicedesk/tickets/",
api_url = "https://psa.pulseway.com/api/",
api_token = "Token",
api_record_limit = 500,
// Build the table based on record start and any filters
fx_api_get_entity_raw = (api_url_filter as any, api_record_start as text, api_entity as text) =>
let
api_url_base = api_url & api_entity & "?api_token=" & api_token & "&start=" & api_record_start & "&limit=" & Text.From(api_record_limit),
api_url_entity = if api_url_filter <> null then api_url_base & api_url_filter else api_url_base,
Source = Json.Document(Web.Contents(api_url_entity)),
data = Source[data],
toTable = Table.FromList(data, Splitter.SplitByNothing(), null, null, ExtraValues.Error)
in
toTable,
// Recursively call the build table function
fxGetEntity = (optional api_record_start as text) as table =>
let
result = fx_api_get_entity_raw(api_url_filter, api_record_start, api_entity),
nextStart = Text.From(Number.From(api_record_start) + api_record_limit),
nextTable = Table.Combine({result, #fxGetEntity(nextStart)}),
check = try nextTable otherwise result
in
check,
resultTable = fxGetEntity("0"),
expandColumn = Table.ExpandRecordColumn(
resultTable,
"Column1",
Record.FieldNames(resultTable{0}[Column1]),
List.Transform(Record.FieldNames(resultTable{0}[Column1]), each _)
)
in
expandColumn
QUESTION TO OP:
Regarding this line:
Result = Source[Result],
Does the json return a field called result instead of data?

How to save string as json in scala spark

I have the raw of string in logs file . I do many filter and other operation after that . I have reached the following problem as below. I need to convert the string into json format . So that i can save it as a single object.
Suppose i have the following data
Val CDataTime = "20191012"
Val LocationId = "12345"
Val SetInstruc = "Comm=Qwe123,Elem=12345,Elem123=Test"
I am trying to create a data frame that contains datetime|location|jsonofinstruction
The Jsonofstring is the json of third Val; I try to split the string first by comma than by equal to sign and loop through by 2 and create a map of value of one and 2 as value. But json not created . Please help here.
You can use scala.util.parsing.json.JSONObject to convert a map to JSON and then to a string.
val df = spark.createDataset(Seq("Comm=Qwe123,Elem=12345,Elem123=Test")).toDF("col3")
val dfWithJson = df.map{ row =>
val insMap = row.getAs[String]("col3").split(",").map{kv =>
val kvArray = kv.split("=")
(kvArray(0),kvArray(1))
}.toMap
val insJson = JSONObject(insMap).toString()
(row.getAs[String]("col3"),insJson)
}.toDF("col3","col4").show()
Result -
+--------------------+--------------------+
| col3| col4|
+--------------------+--------------------+
|Comm=Qwe123,Elem=...|{"Comm" : "Qwe123...|
+--------------------+--------------------+

Loading JSON data via DataPortal into Parameter

I want to load Data from a JSON file into my Pyomo Model.
I start with
m = AbstractModel()
m.T = RangeSet(1,48,1)
m.TS = Param(m.T)
dp = DataPortal()
Later I want to load my json file to populate my parameter TS
with
dp.load(param = m.TS, filename = data.json)
The data is a timeseries indexed by integers 1,2,...,48
Thus
it looks like this:
{
"1" : 0.0001,
"2" : 0.1 ,
....,
"48" : 0
}
then i create
create_instance(dp)
I get the folowing error:
RuntimeError: Failed to set value for param=TS, index=1, value=35.676187.
source error message="Index '1' is not valid for indexed component 'TS'"
So I came with a solution to this problem.
The JSON file should be written in this fashion:
{"TS":
[
{'index':1, 'value':1},
{'index':2, 'value':0},
{'index':3, 'value':1},
]
}

How to filter query result to list of strings

I have a query result same as below:
var ptns = from p in db.Patients
select p;
This query returns a list of patients, but I need to filter the result based on DoctorNameID. The DoctorNameID should be in list of doctors as below:
List<string> listofDoctors = usrtodrs.Split(',').ToList();
I have searched a lot but I don't know how to do this. I have tested this query which doesn't work:
var ptns1 = from d in listofDoctors
join p in ptns.ToList() on d equals p.DoctorNameID
select p;
And also this query:
var ptns1 = ptns.ToList()
.Where(a => listofDoctors.Equals(a.DoctorNameID))
.ToList();
Any help?
You can use Contains extension and get the desired result.
var ptns1 = ptns.Where(x => listofDoctors.Contains(x.DoctorNameID)).ToList();
Refer the C# Fiddle with sample data.

marshalling a hash table in ocaml

I have a hash table in ocaml and I want to store this entire hash table as value field in a Berkeley DB. So I am trying to Marshal the hash table using Marshal.to_string. This returns a string but when I try to unmarshal the same string using Marshal.from_string, an Exception is thrown.
Any ideas on what the issue here is?
You have to annotate the type of the value you're unmarshaling. Like so (in top-level):
type t = (string, string) Hashtbl.t;;
let key = "key" in
let t_original : t = Hashtbl.create 1 in
Hashtbl.add t_original key "value";
let t_marshalled = Marshal.to_string t_original [] in
let t_unmarshalled : t = Marshal.from_string t_marshalled 0 in
assert ((Hashtbl.find t_original key) = (Hashtbl.find t_unmarshalled key));;