Generation 操作

Posted 2020-08-30

Empty

Returns an empty collection

1. var emptyCollection1 =Enumerable.Empty<string>();
2. var emptyCollection2 =Enumerable.Empty<Student>();
4. Console.WriteLine("Count: {0} ", emptyCollection1.Count());
5. Console.WriteLine("Type: {0} ", emptyCollection1.GetType().Name);
7. Console.WriteLine("Count: {0} ",emptyCollection2.Count());
8. Console.WriteLine("Type: {0} ", emptyCollection2.GetType().Name);
10. Results:
11. Type:String[]
12. Count:0
13. Type:Student[]
14. Count:0

Range

Generates collection of IEnumerable type with specified number of elements with sequential values, starting from first element.

1. var intCollection =Enumerable.Range(10,10);
2. Console.WriteLine("Total Count: {0} ", intCollection.Count());
4. for(int i =0; i < intCollection.Count(); i++)
5. Console.WriteLine("Value at index {0} : {1}", i, intCollection.ElementAt(i));
7. Results:
8. TotalCount:10
9. Value at index 0:10
10. Value at index 1:11
11. Value at index 2:12
12. Value at index 3:13
13. Value at index 4:14
14. Value at index 5:15
15. Value at index 6:16
16. Value at index 7:17
17. Value at index 8:18
18. Value at index 9:19

Repeat

Generates a collection of IEnumerable type with specified number of elements and each element contains same specified value.

1. var intCollection =Enumerable.Repeat<int>(10,10);
2. Console.WriteLine("Total Count: {0} ", intCollection.Count());
4. for(int i =0; i < intCollection.Count(); i++)
5. Console.WriteLine("Value at index {0} : {1}", i, intCollection.ElementAt(i));
7. Results:
8. TotalCount:10
9. Value at index 0:10
10. Value at index 1:10
11. Value at index 2:10
12. Value at index 3:10
13. Value at index 4:10
14. Value at index 5:10
15. Value at index 6:10
16. Value at index 7:10
17. Value at index 8:10
18. Value at index 9:10