I have this:
List<string> s = new List<string>{"", "a", "", "b", "", "c"};
I want to remove all the empty elements ("") from it quickly (probably through LINQ) without using a foreach statement because that makes the code look ugly.
4 Answers
You can use List.RemoveAll:
C#
s.RemoveAll(str => String.IsNullOrEmpty(str));
VB.NET
s.RemoveAll(Function(str) String.IsNullOrEmpty(str))
4 Comments
Paolo Moretti
I would simply write
s.RemoveAll(String.IsNullOrEmpty);, you don't need a lambda in this case.
Tim Schmelter
@PaoloMoretti: +1 Good point. But at least in VB.NET it isn't really shorter:
s.RemoveAll(AddressOf String.IsNullOrEmpty) and the lamdba shows that it's possible to modify it easily. Imho it's more readable with the lambda.
Jan Chalupa
Why is it returning number of removed elements instead of cleared list? This
int count = s.RemoveAll(string.IsNullOrEmpty); is valid but List<string> list = s.RemoveAll(string.IsNullOrEmpty); not.Tim Schmelter
Because creating a new list with the removed elements would be a much more expensive operation than simply returning the count of removed elements. Note that the method should only remove elements and the return value is just an information that can be provided because it's already available. If you need to get a list of matching elements have a look at List.FindAll.
Check out with List.RemoveAll with String.IsNullOrEmpty() method;
Indicates whether the specified string is null or an Empty string.
s.RemoveAll(str => string.IsNullOrEmpty(str));
Here is a DEMO.
Comments
s = s.Where(val => !string.IsNullOrEmpty(val)).ToList();
I write below code to remove the blank value
List<string> s = new List<string>{"", "a", "", "b", "", "c"};
s = s.Where(t => !string.IsNullOrWhiteSpace(t)).Distinct().ToList();
stringarray but a list.