I need to get the count of a generic list in C#.No need to consider empty and null items in the count of list.
Below is my code
Public class Student
{
public string Name {get;set;}
public string Age {get;set;}
}
List<student> listStudent = new List<student>();
Student studentOne=new Student();
studentOne.Name="abc";
studentOne.Age="20";
listStudent.Add(studentOne);
Student studentTwo=new Student();
studentOne.Name="def";
studentOne.Age="22";
listStudent.Add(studentTwo);
Student studentThree=new Student();
studentOne.Name=" ";
studentOne.Age=null;
listStudent.Add(studentThree);
I have written below code to get the count
listStudent.count
It returns 3.it is correct as it contains 3 rows in the list.But I need to get the count of elements or items only having values. here in my code values in last item is null or empty.so I need to get count as 2.
Is there any built in method in c# to do the same. is there any way to check without using loops ?
LINQ can help here:
listStudent.Where(
s => !string.IsNullOrWhiteSpace(s.Name) && s.Age != null
).Count();
There is no method in framework that you are looking for. You need to create your own extended method to make this.
Related
Assume I have the following as the value in an IMap:
public class Employee{
public int empId;
public List<String> categories;
public List<String> getCategories(){
return this.categories;
}
}
I would like to find all employees that belong to category "Sales". Also, I would like to create an index on getCategories() so that the query returns fast. There seems to be no Predicate available to do this. How do I go about achieving this? It seems like I will have to write a Predicate to do this. Is there example code I can look at that would show me how to build a predicate that uses an index ?
The only way I currently see this happening is to denormalize the data model and use something like a IMap and the following as value:
class EmployeeCategory{int employeeId, String category}
And put an index on category.
It is somewhere on the backlog to provide more advances indices that should be able to do this out of the box.
I tried by iterating the List to a separate Imap and then querying it in the client.
IMap<String,ArrayList< categories >> cache=hazelcastInstance.getMap("cache");
IMap<String, categories> cachemodified = hazelcastInstance.getMap("cachemodified") ;
int[] idx = { 0 };
xref.get("urkey").forEach(cachefelement ->{
cachemodified.put(String.valueOf(idx[0]++),cachefelement);
});
Predicate p = Predicates.equal("categoryId", "SearchValue");
Collection<categories> result = cachemodified.values(p);
I have the follwing objects
objItem (id,name,qty) - list<items>
objSel(selId) - list<int>
objSel.selId is the selected item id of objItem.
How to write the LINQ query to change item qty to 0 if the items are not selected and return objItem.
Your pseudo-code is quite confusing, but I suspect you want something like:
List<Item> items = ...;
List<int> selectedIds = ...;
foreach (var item in items.Where(x => !selectedIds.Contains(x.Id)))
{
item.Quantity = 0; // Property name adjusted for readability and convention
}
For more efficiently, use HashSet<int> for the selected IDs instead.
Note that it's not the LINQ query which performs the change - the query just gives the items which require changing. While you can abuse LINQ to change data, it's a bad idea to do so. The clue is in the word "query" - it's about asking a question. What you do with the answer to that question is a different matter.
i'm implementing a sand box solution where is should have more than one column a unique key, i have to use the item adding event receiver but how to get the current adding item field values to know if this item is occurred within the list.
thanks
Create UniqueID column and make it unique.
Create an event receiver as follows:
public override void ItemAdding(SPItemEventProperties properties)
{
string Name = properties.AfterProperties["Name"].ToString();
string Title = properties.AfterProperties["Title"].ToString();
StringBuilder StringBuilder = new StringBuilder(Name);
StringBuilder.Append("-");
StringBuilder.Append(Title);
properties.AfterProperties["UniqueID0"] = StringBuilder.ToString();
base.ItemAdding(properties);
}
I am wondering about how to search in J2ME. I have been searching in the internet, so many result show to me, and I see in Java2s.com I got a result use RecordFilter and matches method for search in record store.
But my problem is, when I need to pass 2 or more parameters into it. How can result matches with these parameter?
And how to sort descending or ascending like bubble sort?
Concatenate your searches into a single String variable. Separate each of them with ; for example. In the code of the matches method explode the String to get each search criteria.
To make the filter in effect create an instance of SearchFilter and call the matches method with the concantenated String as its param.
For the sort implement the RecordComparator interface ; implement the compare method to build your sort criteria. Make a google search about j2me+recordcomparator to see examples about how to make sorts.
EDIT :
In the code of the matches method explode the String param obtained from the byte[] param. Treat each String exploded to make the criteria.
As I understand you want to pass two string as a search criteria when you wrote :
SearchFilter search = new SearchFilter(txtSearch.getString(), strType);
So in the constructor there should be two params !!!
When you want to make the matching then call
if searchFilter.matches((search1+";"+sType).getBytes())
Then explode the candidate param into two String when you code the matches method.
When I save my Data in RMS I save it as a String[] like I want to save Name, Age,Salary,EmpID for each employee I save it create an array and convert it to bytes and save it in RMS. When i retrieve it i do the reverse process. Now if i want to get employee with names starting with A and with salary 10000 i use the following filter
class UtilFilter implements RecordFilter{
public UtilFilter(String str_searchText,String str_searchText1)
{
this.str_searchText = str_searchText.toLowerCase();
this.str_searchText1 = str_searchText1.toLowerCase();
}
public boolean matches(byte[] bt_byteData)
{
String str_str = "";
String str_str1 = "";
//here goes code how u get back ur String[] from RMS say u get it in Data
str_str = Data[0].trim();
str_str1 = gd_cd.Data[2].trim();
if(str_searchText != null && str_searchText1 != null && str_str.equals(str_searchText) && str_str1.equals(str_searchText1 ))
{
return true;
}
else
{
return false;
}
}
}
This way i can filter any no of parameters.Hope tht helps! :)
I would like to find the index of an item inside a GWT Listbox by specifying a String value.
For example, if I had a GWT ListBox comprising the following items: "Randy", "Bob" and "Helen", the method i'm looking to implement would return the value 1 if I called it with parameter "Bob".
From what i'm seeing in the ListBox javadoc, ther does not seem to be any quick method to do this.
Any ideas?
Thanks in advance!
My idea of implementation as TextBox doesn't provide this out of the box. Store all the items in a list and in the order you want them to be part of ListBox.
List<String> orderedItems=new ArrayList<String>
orderedItems.add(0,"Randy");
orderedItems.add(1,"Bob");
orderedItems.add(2,"Helen");
//adding items in the same order as they are in List is the key
for(String item:items)
{
lb.addItem(item);
}
then you can find the index using List's indexOf(..) method