LINQ for string StartsWith some value in List <string>
I am parsing XDocument using LINQ. I want to check if one of the XElements with key "BusinessStructure" is working with one of the lines in mine List<string> filters
. In other words, let's say I have:
x.Element("BusinessStructure").Value = "testing123"
and
var filters = new List<string> {"test", "hello"}
Using LINQ, how would I then do something like ...
...
where x.Element("BusinessStructure").Value.StartsWith(filters[0])
select new...
But instead of getting the first index of the filter list, I want to loop over all the values in the list and check if the XElement starts with it. Is this possible with LINQ or do I need to do it with foreach
?
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You can make a direct LINQ solution by slightly modifying your query:
let bs = x.Element("BusinessStructure")
where bs != null && filters.Any(f => bs.Value.StartsWith(f))
Or you can create a regular expression from your filters:
var prefixRegex = new Regex("\\A" + string.Join("|",filters.Select(f=>Regex.Escape(f)));
...
let bs = x.Element("BusinessStructure")
where bs != null && prefixRegex.IsMatch(bs.Value)
If performance is a consideration, try measuring both.
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