person[] prn =
new person[]
{
new person { Name = "Robert", RList =
{new ReceipeList { NameofRecipie = "Coak" },
new ReceipeList { NameofRecipie = "Pizza" } } },
new person { Name = "Rahim", RList =
{ new ReceipeList { NameofRecipie = "Coak" },
new ReceipeList { NameofRecipie = "OnionBread" }} },
};
When searching an item
ReceipeList lstr = new ReceipeList();
lstr.NameofRecipie = "Coak";
using
var query = from lst in prn where(lst.RList.Contains(lstr) ) select lst;
it did not return any result.
foreach (var v in query)
{
Console.Write(v.Name.ToString()+" ordered :");
foreach(ReceipeList lst in v.RList)
{
Console.Write(lst.NameofRecipie.ToString()+",");
}
Console.WriteLine();
}
This isn't working because you're searching for a specific instance of ReceipeList (by reference). Because of this, your query will only return values that have your specific lstr instance of ReceipeList, not a ReceipeList with the same value as the one you're specifying.
You could make this work by overriding Equals in ReceipeList, or by reworking your query to:
string lstr = "Coak";
var query = from lst in prn
where lst.RList.Any(r => r.NameofRecipie == lstr)
select lst;
This works because it uses the Any() method to search the ReceipeList instances by a predicate, instead of searching for a specific instance.
Im Not sure if, but you can look at this also, might help a little bit?
Related
I have method to add elements to list
Here is code
public static List<InputDevice> GetAudioInputDevices()
{
var inputs = new List<InputDevice>();
var enumerator = new MMDeviceEnumerator();
var devicesAudio = enumerator.EnumerateAudioEndPoints(DataFlow.Capture, DeviceState.All);
foreach (var device in devicesAudio)
{
inputs.Add(new InputDevice()
{
Name = device.FriendlyName,
Status = device.State.ToString(),
DeviceId = device.ID,
Identifier = device.FriendlyName.Replace(" ", "").ToUpper()
});
}
return inputs;
}
But sometimes I can have duplicates in Identifier
How I can return list without duplicates on return?
There's a few ways to accomplish this, you could just skip the Adding of the item if it's already in the list:
foreach (var device in devicesAudio)
{
string identifier = device.FriendlyName.Replace(" ", "").ToUpper();
if (inputs.Any(input => input.Identifier == identifier))
continue;
inputs.Add(new InputDevice()
{
Name = device.FriendlyName,
Status = device.State.ToString(),
DeviceId = device.ID,
Identifier = identifier
});
}
Or you could group the list by the identifier after the foreach, something like this:
inputs = inputs.GroupBy(i => i.Identifier)
.Select(i => new InputDevice()
{
Identifier = i.Key,
Status = i.First().Status,
DeviceId = i.First().DeviceId,
Name = i.First().Name
}).ToList();
It really depends on what you need to do with the duplicated ones.
Hope it helps!
To make it faster you can use HashSet (complexity of Contains for HashSet is o(1)) and ask on each loop whether there already is a specific identifier in inputs List.
public static List<InputDevice> GetAudioInputDevices()
{
var inputs = new List<InputDevice>();
var enumerator = new MMDeviceEnumerator();
var devicesAudio = enumerator.EnumerateAudioEndPoints(DataFlow.Capture, DeviceState.All);
var usedIdentifiers = new HashSet<string>();
foreach (var device in devicesAudio)
{
var identifier = device.FriendlyName.Replace(" ", "").ToUpper();
if (usedIdentifiers.Contains(identifier))
continue;
inputs.Add(new InputDevice()
{
Name = device.FriendlyName,
Status = device.State.ToString(),
DeviceId = device.ID,
Identifier = identifier
});
usedIdentifiers.Add(identifier);
}
return inputs;
}
The best way, I thing is this
public static List<InputDevice> GetAudioInputDevices()
{
var inputs = new List<InputDevice>();
var enumerator = new MMDeviceEnumerator();
var devicesAudio = enumerator.EnumerateAudioEndPoints(DataFlow.Capture, DeviceState.All);
inputs = devicesAudio.GroupBy(d => d.FriendlyName.Replace(" ", "").ToUpper()).Select(g => g.First())
.Select(d => new InputDevice()
{
Name = d.FriendlyName,
Status = d.State.ToString(),
DeviceId = d.ID,
Identifier = d.FriendlyName.Replace(" ", "").ToUpper()
}).ToList();
return inputs;
}
Check in website information about HashSet.
Does anyone know how to do multiple aggregations with nest?
I have found quite a few examples unfortunately none of them work.
Here's what I have:
Vehicles fields = new Vehicles();
//create a terms query
var query = new TermsQuery
{
IsVerbatim = true,
Field = "VehicleOwnerId",
Terms = new string[] { 25 },
};
var aggregations = new Dictionary<string, IAggregationContainer>
{
{ "years", new AggregationContainer
{
Terms = new TermsAggregation(nameof(fields.Year))
{
Field = new Field(nameof(fields.Year))
}
}
}
//,
//{ "makes", new AggregationContainer
// {
// Terms = new TermsAggregation("Make")
// {
// Field = new Field(nameof(fields.Make))
// }
// }
//}
};
//create the search request
var searchRequest = new SearchRequest
{
Query = query,
From = 0,
Size = 100,
Aggregations = aggregations
};
var result = client.SearchAsync<InventoryLiveView>(searchRequest).Result;
var years = result.Aggregations.Terms("years");
Dictionary<string, long> yearCounts = new Dictionary<string, long>();
foreach (var item in years.Buckets)
{
yearCounts.Add(item.Key, item.DocCount ?? 0);
}
If I just execute the code like this it works. Years returns the aggregates as expected. If I try to add another field (like the one commented out above) it fails and I get zero records.
How can I get multiple aggregates in one query? I see examples of it all over, but none of the examples I've tried seem to work and most seem to be outdated (including some in the Nest documentation).
I have also tried this approach which is pretty close to the documentation.
//create the search request
var searchRequest = new SearchRequest
{
Query = query,
From = 0,
Size = 100,
//Aggregations = aggregations
Aggregations = new AggregationDictionary
{
{
"childAgg", new ChildrenAggregation("childAgg", typeof(Vehicles ))
{
Aggregations = new AggregationDictionary
{
{"years", new TermsAggregation(nameof(fields.VehicleYear))},
{"makes", new TermsAggregation(nameof(fields.VehicleMakeName))},
{"models", new TermsAggregation(nameof(fields.VehicleModelName))},
}
}
}
}
};
var result = client.SearchAsync<Vehicles>(searchRequest).Result;
This just produces a null reference exception.
I guess I'll never have too worry about getting to proud as a programmer :)
It's too often that the solution to the problem makes me feel stupid when it reveals itself.
So my issue was that the field I was trying to use in the aggregation was text and couldn't be used. I switched everything to the ID fields and multiple aggregations work as expected.
So this version of the code works like a champ:
Vehicle fields = new Vehicle ();
//create a terms query
var query = new TermsQuery
{
IsVerbatim = true,
Field = "VehicleOwnerId",
Terms = new string[] { "30" },
};
string[] Fields = new[]
{
nameof(fields.Year),
nameof(fields.MakeId),
nameof(fields.ModelId)
};
var aggregations = new Dictionary<string, IAggregationContainer>();
foreach (string sField in Fields)
{
var termsAggregation = new TermsAggregation(sField)
{
Field = sField
};
aggregations.Add(sField, new AggregationContainer { Terms = termsAggregation });
}
//create the search request
var searchRequest = new SearchRequest
{
Query = query,
From = 0,
Size = 10,
Aggregations = aggregations
};
var result = client.SearchAsync<InventoryLiveView>(searchRequest).Result;
var years = result.Aggregations.Terms(nameof(fields.Year));
Dictionary<string, long> yearCounts = new Dictionary<string, long>();
foreach (var item in years.Buckets)
{
yearCounts.Add(item.Key, item.DocCount ?? 0);
}
The exact error from elasticsearch, which I saw using postman was:
Fielddata is disabled on text fields by default. Set fielddata=true on [MakeName] in order to load fielddata in memory by uninverting the inverted index. Note that this can however use significant memory. Alternatively use a keyword field instead.
Here is my example using SearchDescriptors. My only problem is how to serialize returned results into a proper Key Value list. Is Looping through a fields list the best way to return results.
SearchDescriptor<Advert> agghDescriptor = new SearchDescriptor<Advert>();
agghDescriptor.Aggregations(ag => ag.Terms("make", a => a.Field(f => f.Make)) &&
ag.Terms("region", a => a.Field(f => f.Region)) &&
ag.Terms("city", a => a.Field(f => f.City)) &&
ag.Terms("category", a => a.Field(f => f.Category)) &&
ag.Terms("application", a => a.Field(f => f.Application)) &&
ag.Terms("portalId", a => a.Field(f => f.PortalId)) &&
ag.Terms("isActiveAuctionAdvert", a => a.Field(f => f.IsActiveAuctionAdvert)) &&
ag.Terms("isBargainAccount", a => a.Field(f => f.IsBargainAccount)) &&
ag.Terms("condition", a => a.Field(f => f.Condition))
);
agghDescriptor.Size(0);
var json2 = _client.RequestResponseSerializer.SerializeToString(agghDescriptor);
var aggregationResult = _client.Search<Advert>(agghDescriptor);
List<string> fields = new List<string>();
fields.Add("make");
fields.Add("category");
fields.Add("region");
List<Aggregation> aggregations = new List<Aggregation>();
foreach (var field in fields)
{
var aggrs = aggregationResult.Aggregations.Terms(field);
List<AggregateItem> aggregateItems = new List<AggregateItem>();
foreach (var item in aggrs.Buckets)
{
aggregateItems.Add(new AggregateItem()
{
Count = item.DocCount ?? 0,
Key = item.Key
});
}
aggregations.Add(new Aggregation()
{
Name = field,
Aggregates = aggregateItems
});
}
I have an object in my database, i.e. with 10 attributes.
Now I want to let the user select some of them (1 or 2 up to 10 of them) and then according by user's selection I make a list of object with the attributes selected by user
the scenario that I think about is this:
A page with check boxes that shows the attributes(columns) of that abject then user selects each of them he needs.
But here is my problem, how to make the selected check boxes run as query?
For example user selected col 1 , col 2, col 6 , col 10, how can I write a query responsible for user selection?
Example I wanna the meaningful phrase of this:
var file2 = file.Select(f => new { "attributes selected by user" }).OrderBy(what user wants)
they System.Linq.Dynamic library on Nuget is a way to go
[TestMethod]
public void StringyAndDangerous()
{
var fakePersonDbSet = new List<Person> { new Person() { FirstName = "Some", LastName = "Guy" } }.AsQueryable();
var attributes = new string[] { "FirstName", "LastName" };
var selectedFields = String.Join(",", attributes);
var exprssion = string.Format("new ({0})", selectedFields);
var result = fakePersonDbSet.Select(exprssion, attributes).Cast<dynamic>().First();
}
but you loose type safety and compile time checking. You might be better taking another approach
[TestMethod]
public void SlowerButSafer()
{
var fakePersonDbSet = new List<Person> { new Person() { FirstName = "Some", LastName = "Guy" } }.AsQueryable();
var attributes = new string[] { "FirstName", "LastName" };
var personPropertylist = CovertToKeyValuePair(fakePersonDbSet.First())
.Where(c=> attributes.Contains(c.Key))
.ToArray();
}
private IEnumerable<KeyValuePair<string, object>> CovertToKeyValuePair<T>(T #object)
{
var result = new List<KeyValuePair<string, object>>();
var properties = typeof (T).GetProperties();
foreach (var property in properties)
{
result.Add(new KeyValuePair<string, object>(property.Name, property.GetValue(#object, null)));
}
return result;
}
you'll take a performance hit both for pulling fields from the database that you don't need and for using reflection but the code will be less error prone and you won't end up with errors for trying to select columns that don't exist.
Use DynamicLinq. (link)
Extension methods:
public static T GetValue<T>(this DynamicClass dynamicObject, string propName)
{
if (dynamicObject == null)
{
throw new ArgumentNullException("dynamicObject");
}
var type = dynamicObject.GetType();
var props = type.GetProperties(BindingFlags.Public
| BindingFlags.Instance
| BindingFlags.FlattenHierarchy);
var prop = props.FirstOrDefault(property => property.Name == propName);
if (prop == null)
{
throw new InvalidOperationException("Specified property doesn't exist.");
}
return (T)prop.GetValue(dynamicObject, null);
}
public static string ToDynamicSelector(this IList<string> propNames)
{
if (!propNames.Any())
throw new ArgumentException("You need supply at least one property");
return string.Format("new({0})", string.Join(",", propNames));
}
Usage:
using System.Linq.Dynamic;
// ..
var columns = new[] { "col1", "col2", etc };
var result = context.Files.OrderBy(file => file.Id)
.Select(columns.ToDynamicSelector())
.Cast<DynamicClass>.ToList();
Result will be the collecion of DynamiClass instances wchich columns will contain selected properties.
To get single property from DynamicClass:
var columnValue = result.First().GetValue<string>("col1");
If you want to get values from IEnumerable:
var list = new List<File> { File1, File2, etc.. };
var result = list.AsQueryable().Select( /* the same as above */);
I need to preform a query that check if a collection is in given collection, just like the regular in operation but for collections.
class Post
{
public string[] Tags {get;set;}
}
session.Queury<Post>.Where(x=>x.Tags.in(new[]{".net","c#","RavenDB"})).ToList();
so if i have in my DB:
new Post{Tags= new[]{"C#",".net"}};
it will be returned
but if i have:
new Post{Tags= new[]{"C#",".net","SQLServer"}};
it will not be returned.
Update:
what i am trying to do is this:
session.Query<Post>()
.Where(x => x.Tags.All(y => y.In(new[] { "C#", ".net", "RavenDB" })))
.ToList();
but i got System.NotSupportedException.
I manage to find a solution:
static void Main(string[] args)
{
var sessionStore = new EmbeddableDocumentStore
{
RunInMemory = true,
UseEmbeddedHttpServer = true,
Conventions =
{
DefaultQueryingConsistency = ConsistencyOptions.AlwaysWaitForNonStaleResultsAsOfLastWrite
}
};
sessionStore.Initialize();
using (var session = sessionStore.OpenSession())
{
var allTags = new[] {"C#", ".net", "RavenDB", "Linux", "Mac"};
var tagsCollection = new[] {"C#", ".net", "RavenDB"};
var complementTagsCollection = allTags.Except(tagsCollection).ToList();
session.Store(new Post
{
Tags = new List<string>{"C#",".net"}
});
session.SaveChanges();
// Posts where all their tags are in tagsCollection
var result = session.Query<Post>().Where(x => !x.Tags.In(complementTagsCollection)).ToList();
}
}
The way IN works, it matches ANY of them.
If you want to match all you have to do a separate check for each.
I am working on below code, and what I want to do is query by object itself.
For example: I have a search form, that populates objects fields such as below. Then what I want to do is to search Elastic search based on whatever user filled the form with.
ie: below, I want to query the index by searchItem object. How can I do it easily?
class Program
{
static void Main(string[] args)
{
var p = new Program();
var item1 = new Announcement() {Id=1, Title = "john", ContentText = "lorem", Bar = false, Num = 99, Foo = "hellow"};
//p.Index(item1, "add");
var searchItem = new Announcement() {Title="john",Num=99};
ElasticClient.Search<Announcement>();
Console.Read();
}
public void Index(Announcement announcement, String operation)
{
var uriString = "http://localhost:9200";
var searchBoxUri = new Uri(uriString);
var settings = new ConnectionSettings(searchBoxUri);
settings.SetDefaultIndex("test");
var client = new ElasticClient(settings);
if (operation.Equals("delete"))
{
client.DeleteById("test", "announcement", announcement.Id);
}
else
{
client.Index(announcement, "test", "announcement", announcement.Id);
}
}
private static ElasticClient ElasticClient
{
get
{
try
{
var uriString = "http://localhost:9200";
var searchBoxUri = new Uri(uriString);
var settings = new ConnectionSettings(searchBoxUri);
settings.SetDefaultIndex("test");
return new ElasticClient(settings);
}
catch (Exception)
{
throw;
}
}
}
}
You can't :)
NEST cannot infer how to best query only based on a partially filled POCO. Should it OR or AND should it do a nested term query or a term query wrapped in a has_child? You catch my drift.
Nest does have a slick feature called conditionless queries that allow you the write out to entire query like so:
ElasticClient.Search<Announcement>(s=>s
.Query(q=>
q.Term(p=>p.Title, searchItem.Title)
&& q.Term(p=>p.Num, searchItem.Num)
//Many more queries use () to group all you want
)
)
When NEST sees that the argument passed to Term is null or empty it simply wont render that part of the query.
Read more here on how this feature works http://nest.azurewebsites.net/concepts/writing-queries.html