C# Linq Queries
A super valueable skill that is worth knowing and practicing on a weekly basis is Language Integrated Query or LinQ statements. Linq statements can be defined in c# and extract data from various object types. The flexibility of being able to apply a uniform language to extract data to different object types is what makes linq so valuable.
The example for this post can be found here .
We have two arrays of strings, the first has strings the word version of 1 - 10, the second has a-z as characters.
String[] QueryString = {"One","Two","Three","Four","Five","Six","Seven","Eight","Nine","Ten"};
String[] IndexArray = {"A","B","C","D","E","F","G","H","I","J","K","L","M","N","O","P","Q","R","S","T","U","V","W","X","Y","Z"};
A typical linq query may look like this
var ThisQuery =
from StringValue in QueryString
Additional clauses similar to SQL clauses can be applied to linq queries, although many keys words are the same as in SQL there are several drastic differences in Linq.
You can apply custom methods to result sets, use logic to narrow in on the selectivity your after, define ordering and much more in linq. As a simple example I will join the two string arrays together on the matching first letter of each word in the QueryString array and print the results.
String[] QueryString = {"One","Two","Three","Four","Five","Six","Seven","Eight","Nine","Ten"};
String[] IndexArray = {"A","B","C","D","E","F","G","H","I","J","K","L","M","N","O","P","Q","R","S","T","U","V","W","X","Y","Z"};
var ThisQuery =
from StringValue in QueryString
join IndexValue in IndexArray
on StringValue.Substring(0, 1) equals IndexValue
where Convert.ToChar(IndexValue) > 'F' //Added Where Filter here...
orderby IndexValue //Order By Clause must be written as orderby (lowercase)
select new {StringValue, IndexValue};
foreach (var ThisValue in ThisQuery)
Console.WriteLine(ThisValue.IndexValue + " - " + ThisValue.StringValue + "\r\n");
