I'm trying to query a database using something like this:
let db = drop.database?.driver as? MySQLDriver
let query = "select \(fields) from \(table) where \(condition)"
let result = try db.raw(query)
I get the following Node object as result:
array([Node.Node.object(["field_name": Node.Node.string("value_info")])])
How can I get the value_info into a String variable?
You can use PathIndexable to step into the result object, then Polymorphic to cast it as a string.
Should look something like this:
let valueInfo = result[0, "field_name"]?.string
Related
Since two days I'm on a problem and I can't solve it so I come here to ask some help...
I have that bit of dax that basically take the path of a hierarchical table (integers) and take the string names of the 2 first in the path.
the names I use:
'HIERARCHY' the hierarchical table with names, id, path, nbrItems, string
mytable / addedcolumn1/2 the new table used to emulate the for loop
DisplayPath =
var __Path =PATH(ParentChild[id], ParentChild[parent_id])
var __P1 = PATHITEM(__Path,1) var __P2 = PATHITEM(__Path,2)
var l1 = LOOKUPVALUE(ParentChild[Place],ParentChild[id],VALUE(__P1))
var l2a = LOOKUPVALUE(ParentChild[Place],ParentChild[id],VALUE(__P2))
var l2 = if(ISBLANK(l2a), "", " -> " & l2a)
return CONCATENATE(l1,l2)
My problem is... I don't know the number of indexes in my path, can go from 0 to I guess 15...
I've tried some things but can't figure out a solution.
First I added a new column called nbrItems which calculate the number of items in the list of the path.
The two columns:
Then I added that bit of code that emulates a for loop depending on the number of items in the path list, and I'd like in it to
get name of parameters
concatenate them in one string that I can return and get
string =
var n = 'HIERARCHY'[nbrItems]
var mytable = GENERATESERIES(1, n)
var addedcolumn1 = ADDCOLUMNS(mytable, "nom", /* missing part: get name */)
var addedcolumn2 = ADDCOLUMNS(addedcolumn1, "string", /* missing part: concatenate previous concatenated and new name */)
var mymax = MAXX(addedcolumn2, [Value])
RETURN MAXX(FILTER(addedcolumn2, [Value] = mymax), [string])
Full table:
Thanks for your help in advance!
Ok, so after some research and a lot of try and error... I've came up to a nice and simple solution:
The original problem was that I had a hierarchical table ,but with all data in the same table.
like so
What I did was, adding a new "parent" column with this dax:
parent =
var a = 'HIERARCHY'[id_parent]
var b = CALCULATE(MIN('HIERARCHY'[libelle]), FILTER(ALL('HIERARCHY'), 'HIERARCHY'[id_h] = a))
RETURN b
This gets the parent name from the id_parent (ref. screen).
then I could just use the path function, not on the id's but on the names... like so:
path = PATH('HIERARCHY'[libelle], 'HIERARCHY'[parent])
It made the problem easy because I didn't need to replace the id's by there names after this...
and finally to make it look nice, I used some substitution to remove the pipes:
formated_path = SUBSTITUTE('HIERARCHY'[path], "|", " -> ")
final result
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.
I am using a web service to get information. When said info is returned, I convert the data received from jason to a dict.
When Dumping dict object, some of the items arrive like this:
▿ (2 elements)
- key: "street1"
- value: <null> #4
How would i go about reading this data and knowing that the value is NULL
I have tried the following:
let street1:String = dict?["street1"] as! String
This fails with: Could not cast value of type 'NSNull' (0x10fbf7918) to 'NSString' (0x10f202c60).
The data could have a String value. So I tried:
let street1:Any = dict?["street1"] as Any
When I print street1 thus
street1: Optional()
I get the following
street1: Optional()
So my question is:
How would i go about reading this data and knowing that the value is null.
You can use if let for this type of nil check.
Try this instead:
if let street1 = dict?["street1"] as? String {
// If this succeeds then you can use street1 in here
print(street1)
}
Update:
var t_street1 = ""
if let street1 = dict?["street1"] as? String {
t_street1 = street1
}
No need for the else t_street1 is automatically empty since you assign it empty.
I have the following code:
let numberFormatter = NumberFormatter()
numberFormatter.numberStyle = NumberFormatter.Style.decimal
numberFormatter.maximumFractionDigits = 2
let formattedNumber = numberFormatter.string(from: NSNumber(value: rawValue))
currentLogBF.text = "\(formattedNumber) BF"
In the above example, rawValue is a Double that is calculated when all of the input fields have values in them.
currentLogBF is a label in my View.
Whenever a calculation is completed, the label displays something like this:
Optional("12,307.01") BF
How do I get rid of the "Optional()" piece, so it just displays this:
12,307.01 BF
Any ideas what I am doing wrong here?
The function numberFormatter.string(from: NSNumber) will return you a String Optional (String?) instead of String.
You will need to unwrap it first like this
if let formattedNumber = numberFormatter.string(from: NSNumber(value: rawValue)) {
currentLogBF.text = "\(formattedNumber) BF"
} else {
Log.warn("Failed to format number!")
}
And as bonus, use String(format: "%# BF", formattedNumber) rather than "\(formattedNumber) BF" when dealing with optional.
String(format:) will give you compile error when you try to pass optional value as an argument
unwrapping an optional value
let formattedNumber:String? = numberFormatter.string(from: NSNumber(value: rawValue))
currentLogBF.text = "\(formattedNumber!) BF" //optional string. This will result in nil while unwrapping an optional value if value is not initialized or if initialized to nil.
currentLogBF.text = "\(formattedNumber) BF" //Optional("optional string") //nil values are handled in this statement
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));;