I have an Array of [Long, Q] and would like to make a binary search on it. I tried below :
import scala.collection.Searching._
class Q (val b:Double, val a:Double)
val myArray = Array(5L -> new Q(1,2), 6L-> new Q(6,9), 7L-> new Q(7,6))
val i = myArray.search(6L).insertionPoint
but had this error
No implicit Ordering defined for Any
Unspecified value parameter ord.
I understand that I need to specify an odering rule for this collection Array[(Long,Q)] but can't figure this out myself.
Please help
Signature of search is search[B >: A](elem: B)(implicit ord: Ordering[B]). You've got an array of type [Long, Q]. So in order for the compiler to infer Ordering correctly, you'd have to invoke search like that:
myArray.search(6L-> q/*Q(6,9)*/)(Ordering.by(_._1)) //ordering by the first value in a tuple.
and what you're doing is: myArray.search(6L). If I understand correctly what you're trying to do, it's probably to find both value and position in the array.
You could solve it by using two separate data structures:
keys could be stored in the array, like this:
val myArray = Array(5L, 6L, 7L).toList
myArray.search(6L).insertionPoint
and if you'd need values, you could use map which would work as a dictionary:
val dictionary = Map(
5L -> new Q(1,2),
6L-> new Q(6,9),
7L-> new Q(7,6)
)
EDIT:
Actually, I noticed something like that would work:
val dummy = new Q(0,0) //any instance of Q
myArray.search(6L-> dummy)(Ordering.by(_._1)).insertionPoint //1
It works since for lookup of the insertion point Ordering is used and no equality test is performed.
I get data from a URL, and am working on the data to check for a few conditions. The data from the URL look like this:
1528190345":100,"1528190346":100,"1528190368":100,"1528190414":100,"1528190439":99,"1528190440":99,"1528190463":100,"1528190485":100,"1528190508":100,"1528190550":100,"1528190575":100,"1528190576":100,"1528190599":100,"1528190600":100,"1528190622":100,"1528190667":100,"1528190688":100,"1528190689":100,"1528190712":100,"1528190736":100,"1528190762":100,"1528190785":100,"1528190786":100,"1528190807":100,"1528190828":100,"1528190853":100,"1528190877":100,"1528190901":100,"1528190925":100,"1528190948":100,"1528190968":100,"1528190991":100}}]
====
I have converted that too JSON
{"metric"=>"Insta_real-unique_value", "tags"=>{"host"=>"letme.quickly.com", "tier"=>"2", "device"=>"tester1", "dc"=>"xxx"}, "aggregateTags"=>["device_name", "device_ip"], "dps"=>{"1526972408"=>100, "1526972424"=>100, "1526972440"=>100, "1526972456"=>100, "1526972472"=>100, "1526972488"=>100, "1526972504"=>100, "1526972520"=>100, "1526972536"=>100, "1526972552"=>100, "1526972568"=>100, "1526972569"=>100, "1526972584"=>100, "1526972585"=>100, "1526972601"=>100, "1526972617"=>100, "1526972633"=>100, "1526972649"=>100, "1526972665"=>100, "1526972681"=>100}}
I want to extract the value that corresponds to 100. When I do this:
url = "#{URL}"
uri = URI(url)
response = Net::HTTP.get(uri)
value = response[-6..-4]
puts value
I get the last value, but when the last value changes to 99/9/0, it prints :99 or ":9.
Is there a way to get the exact value as is?
When dealing with JSON data, it's almost always better to parse the data properly rather than using regex against the string.
In this case, we can do:
JSON.parse(response)['dps'].values.last #=> 100
If the response is a json response, you must use a json parser else if is not a json response, you can use a regex expression with a Regex Object.
In case of a json response, assuming that the object is something like is declared into the variable response of the next code, you can parse it into a JObject. (using Newtonsoft.Json available from nuget repository).
See the next example :
string response = "[{\"response\":{\"1528190345\":100,\"1528190346\":100,\"1528190368\":100,\"1528190414\":100,\"1528190439\":99,\"1528190440\":99,\"1528190463\":100,\"1528190485\":100,\"1528190508\":100,\"1528190550\":100,\"1528190575\":100,\"1528190576\":100,\"1528190599\":100,\"1528190600\":100,\"1528190622\":100,\"1528190667\":100,\"1528190688\":100,\"1528190689\":100,\"1528190712\":100,\"1528190736\":100,\"1528190762\":100,\"1528190785\":100,\"1528190786\":100,\"1528190807\":100,\"1528190828\":100,\"1528190853\":100,\"1528190877\":100,\"1528190901\":100,\"1528190925\":100,\"1528190948\":100,\"1528190968\":100,\"1528190991\":100}}]";
List<Dictionary<string, Dictionary<string, int>>> values = JsonConvert.DeserializeObject<List<Dictionary<string, Dictionary<string, int>>>>(response);
Dictionary<string, Dictionary<string, int>> firstLevel = values[0]; // Access to the first object of the list closed with ']'
Dictionary<string, int> secondLevel = firstLevel["response"]; // Access to the first object response and get's it's object context of first '}' starting from the end of response
/** This is an option, if you ever knows the name of the element (1528190991) */
int thirdLevel = secondLevel["1528190991"]; // Access to the last element of the object by it's name, context of second '}' starting from the end of response.
Console.WriteLine(thirdLevel);
/** This is another option if you doesn't know the name of the element and wants ever the last element. */
List<int> listOfValues = secondLevel.Values.ToList();
Console.WriteLine(listOfValues[listOfValues.Count-1]);
Note that i've chenged a little bit your response adding [{\"response\":{\" at the start to become a json response.
If is not a json response you can use this pattern with regular expression :
:(.{2,6})}}\]$
Hope will help!
I have a simple MVC C# controller with 2 dimention array.
ViewBag.states = new SelectList(db.states, "state_code", "state_zone");
If state_code = "FL", I want to get its state_zone value in the controller
I tried:
int newZone = ViewBag.states["FL"].state_zone
but I get error:
Cannot apply indexing with [] to an expression of type 'System.Web.Mvc.SelectList'
Any ideas?
Since ViewBag.states is dynamic property, you can't use indexer of SelectList against it because state_zone already stored inside Text property:
int newZone = ViewBag.states["FL"].state_zone;
Also this declaration seems possible but may throwing indexing error as described in comment:
var zone = ViewBag.states as SelectList;
int newZone = Convert.ToInt32(zone.Items[0].Text); // error: 'cannot apply indexing with [] to an expression of type 'System.Collections.IEnumerable'
To use SelectList item indexer inside ViewBag object, you need to convert it into SelectList first, then use LINQ methods to reveal its value:
var zone = ViewBag.states as SelectList;
int newZone = Convert.ToInt32(zone.Skip(n).First().Text); // n = any index number
// alternative:
int newZone = Convert.ToInt32(zone.Where(p => p.Value == "[any_value]").First().Text);
Similar issue:
Get a text item from an c# SelectList
According to the Dapper documentation, you can get a dynamic list back from dapper using below code :
var rows = connection.Query("select 1 A, 2 B union all select 3, 4");
((int)rows[0].A)
.IsEqualTo(1);
((int)rows[0].B)
.IsEqualTo(2);
((int)rows[1].A)
.IsEqualTo(3);
((int)rows[1].B)
.IsEqualTo(4);
What is however the use of dynamic if you have to know the field names and datatypes of the fields.
If I have :
var result = Db.Query("Select * from Data.Tables");
I want to be able to do the following :
Get a list of the field names and data types returned.
Iterate over it using the field names and get back data in the following ways :
result.Fields
["Id", "Description"]
result[0].values
[1, "This is the description"]
This would allow me to get
result[0].["Id"].Value
which will give results 1 and be of type e.g. Int 32
result[0].["Id"].Type --- what datattype is the value returned
result[0].["Description"]
which will give results "This is the description" and will be of type string.
I see there is a results[0].table which has a dapperrow object with an array of the fieldnames and there is also a result.values which is an object[2] with the values in it, but it can not be accessed. If I add a watch to the drilled down column name, I can get the id. The automatically created watch is :
(new System.Collections.Generic.Mscorlib_CollectionDebugView<Dapper.SqlMapper.DapperRow>(result as System.Collections.Generic.List<Dapper.SqlMapper.DapperRow>)).Items[0].table.FieldNames[0] "Id" string
So I should be able to get result[0].Items[0].table.FieldNames[0] and get "Id" back.
You can cast each row to an IDictionary<string, object>, which should provide access to the names and the values. We don't explicitly track the types currently - we simply don't have a need to. If that isn't enough, consider using the dapper method that returns an IDataReader - this will provide access to the raw data, while still allowing convenient call / parameterization syntax.
For example:
var rows = ...
foreach(IDictionary<string, object> row in rows) {
Console.WriteLine("row:");
foreach(var pair in row) {
Console.WriteLine(" {0} = {1}", pair.Key, pair.Value);
}
}
I'm trying to figure out how to execute a custom query with Castle ActiveRecord.
I was able to run simple query that returns my entity, but what I really need is the query like that below (with custom field set):
select count(1) as cnt, data from workstationevent where serverdatetime >= :minDate and serverdatetime < :maxDate and userId = 1 group by data having count(1) > :threshold
Thanks!
In this case what you want is HqlBasedQuery. Your query will be a projection, so what you'll get back will be an ArrayList of tuples containing the results (the content of each element of the ArrayList will depend on the query, but for more than one value will be object[]).
HqlBasedQuery query = new HqlBasedQuery(typeof(WorkStationEvent),
"select count(1) as cnt, data from workstationevent where
serverdatetime >= :minDate and serverdatetime < :maxDate
and userId = 1 group by data having count(1) > :threshold");
var results =
(ArrayList)ActiveRecordMediator.ExecuteQuery(query);
foreach(object[] tuple in results)
{
int count = (int)tuple[0]; // = cnt
string data = (string)tuple[1]; // = data (assuming this is a string)
// do something here with these results
}
You can create an anonymous type to hold the results in a more meaningful fashion. For example:
var results = from summary in
(ArrayList)ActiveRecordMediator.ExecuteQuery(query)
select new {
Count = (int)summary[0], Data = (string)summary[1]
};
Now results will contain a collection of anonymous types with properties Count and Data. Or indeed you could create your own summary type and populate it out this way too.
ActiveRecord also has the ProjectionQuery which does much the same thing but can only return actual mapped properties rather than aggregates or functions as you can with HQL.
Be aware though, if you're using ActiveRecord 1.0.3 (RC3) as I was, this will result in a runtime InvalidCastException. ActiveRecordMediator.ExecuteQuery returns an ArrayList and not a generic ICollection. So in order to make it work, just change this line:
var results = (ICollection<object[]>) ActiveRecordMediator.ExecuteQuery(query);
to
var results = (ArrayList) ActiveRecordMediator.ExecuteQuery(query);
and it should work.
Also note that using count(1) in your hql statement will make the query return an ArrayList of String instead of an ArrayList of object[] (which is what you get when using count(*).)
Just thought I'd point this out for the sake of having it all documented in one place.