Csharp/C Sharp/LINQ/Contains
Содержание
- 1 A query to extract strings containing the letter "a", sorted by length and converted to uppercase
- 2 Contains with IEqualityComparer
- 3 Contains with predicate returned false
- 4 Contains with string value
- 5 Contains with string value and IEqualityComparer
- 6 Use Contains to check the existance of an element
A query to extract strings containing the letter "a", sorted by length and converted to uppercase
<source lang="csharp"> using System; using System.Collections.Generic; using System.Linq; class LinqDemo {
static void Main() {
string[] names = { "J", "P", "G", "Pa" };
IEnumerable<string> query =
from n in names
where n.Contains("a")
orderby n.Length
select n.ToUpper();
foreach (string name in query) Console.Write(name + "/");
}
}
</source>
Contains with IEqualityComparer
<source lang="csharp"> using System; using System.Linq; using System.Collections; using System.Collections.Generic; public class MyStringifiedNumberComparer : IEqualityComparer<string> {
public bool Equals(string x, string y) {
return (Int32.Parse(x) == Int32.Parse(y));
}
public int GetHashCode(string obj) {
return Int32.Parse(obj).ToString().GetHashCode();
}
} public class MainClass {
public static void Main() {
string[] stringifiedNums = {"001", "49", "017", "0080", "00027", "2" };
bool contains = stringifiedNums.Contains("2",new MyStringifiedNumberComparer());
Console.WriteLine(contains);
}
}
</source>
Contains with predicate returned false
<source lang="csharp"> using System; using System.Linq; using System.Collections; using System.Collections.Generic; public class MainClass {
public static void Main() {
string[] presidents = {"A", "H", "a", "H", "over", "Jack"};
bool contains = presidents.Contains("G");
Console.WriteLine(contains);
}
}
</source>
Contains with string value
<source lang="csharp"> using System; using System.Linq; using System.Collections; using System.Collections.Generic; public class MainClass {
public static void Main() {
string[] presidents = {"G", "H", "a", "H", "over", "Jack"};
bool contains = presidents.Contains("H");
Console.WriteLine(contains);
}
}
</source>
Contains with string value and IEqualityComparer
<source lang="csharp"> using System; using System.Linq; using System.Collections; using System.Collections.Generic; public class MyStringifiedNumberComparer : IEqualityComparer<string> {
public bool Equals(string x, string y) {
return (Int32.Parse(x) == Int32.Parse(y));
}
public int GetHashCode(string obj) {
return Int32.Parse(obj).ToString().GetHashCode();
}
} public class MainClass {
public static void Main() {
string[] stringifiedNums = {"001", "49", "017", "0080", "00027", "2" };
bool contains = stringifiedNums.Contains("000271",new MyStringifiedNumberComparer());
Console.WriteLine(contains);
}
}
</source>
Use Contains to check the existance of an element
<source lang="csharp"> using System; using System.Collections; using System.Collections.Generic; using System.Text; using System.Linq; public class MainClass{
public static void Main(){
int[] numbers = { 2, 6, 1, 56, 102 };
Console.WriteLine("Is there the number 102?");
Console.Write(numbers.Contains(102) ? "Yes, there is" : "No, there isn"t");
}
}
</source>
