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Tip of the Day
Language: .NET
Expertise: Intermediate
Oct 19, 2009

Use Array Predicates to Simplify Searches

Array predicates are a not-so-well-known feature introduced with the .NET Framework 2.0 that let you retrieve specific items or perform operations on all items of an array. For example, a quick way to ensure that none of the parameters passed to a function are empty or null is to use the Any predicate.

As an example, assume a method takes four string parameters. Obviously, one way to determine if any of them are empty is to iterate through the parameters testing each one in turn, but a better method is to use the Any operator. Here's an example:

//gather all the input values.
string[] inputValues = {databaseKey, query, databaseType, password};
//check if the arguments are empty.
if (IsEmpty(inputValues))
   throw new ArgumentException("All values are required.");

//Function to check if the parameter array has any empty values.
private static bool IsEmpty(string[] values)
   return (values.Any(value => string.IsNullOrEmpty(value.Trim())));
Check out other predicate operations described here.
Srinath MS
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