Before using LINQ in C#, please read my earlier blog to get some basic idea about what is LINQ?
LINQ can be used in C# in different ways :
One way is to use with Lambda Expression
Another way is to use Anonymous function
Below code will return string of length less than 5.
string[] countryArr = { “India”, “USA”, “UK”, “China”, “Japan”, “Germany”, “Australia” };
var data = countryArr.Where(a => a.Length < 5).Select(a => a);
foreach (string sdata in data)
{
Console.WriteLine(sdata);
}
O/P : – USA, UK
Above code can be written using Anonymous function
Write below function
Func<string, bool> wh = delegate (string s)
{ return s.Length < 5; };
Func<string, string> sel = delegate (string s)
{ return s; };
Below function to implement the LINQ
private void PrintData()
{
string[] countryArr = { “India”, “USA”, “UK”, “China”, “Japan”, “Germany”, “Australia” };
var data = countryArr.Where(wh).Select(sel);
foreach (string sdata in data)
{
Console.WriteLine(sdata);
}
}
Below Code to select only integer from given array
object[] arData = { “test”, 1, 10, “my name”, 12, “laptop”, “Mouse”, 20, 22, 25, 50, “LINQ Program” };
var aa = arData.OfType<int>();
foreach (int s in aa)
{
Console.WriteLine(s);
}
Below code to select integer data less than 25 and order by clause from array.
object[] arData = { “test”, 1, 10, “my name”, 12, “laptop”, “Mouse”, 20, 22, 25, 50, “LINQ Program” };
var aa = arData.OfType<int>()
.OrderBy(a => a)
.Where(a => a < 25)
.Select(a => a);
foreach (int s in aa)
{
Console.WriteLine(s);
}
Join in LINQ
There are 2 arrays, below code join 2 arrays to select matching data from 2nd array.
object[] countryMaster = {“INDIA”,“USA”, “UK”,“AUSTRALIA”,“JAPAN”};
object[] country = { “INDIA”,“USA”,“JAPAN”};
var joinData = countryMaster.OfType<string>()
.Join(country.OfType<string>(),
p => p, t => t,
(p, t) => p);
foreach (var s in joinData)
{
Console.WriteLine(s);
}
