Question

For the following block of code:

For I = 0 To listOfStrings.Count - 1     If myString.Contains(lstOfStrings.Item(I)) Then         Return True     End If Next Return False 

The output is:

Case 1:

myString: C:\Files\myfile.doc listOfString: C:\Files\, C:\Files2\ Result: True 

Case 2:

myString: C:\Files3\myfile.doc listOfString: C:\Files\, C:\Files2\ Result: False 

The list (listOfStrings) may contain several items (minimum 20) and it has to be checked against a thousands of strings (like myString).

Is there a better (more efficient) way to write this code?

Answer 1

With LINQ, and using C# (I don’t know VB much these days):

bool b = listOfStrings.Any(s=>myString.Contains(s)); 

or (shorter and more efficient, but arguably less clear):

bool b = listOfStrings.Any(myString.Contains); 

If you were testing equality, it would be worth looking at HashSet etc, but this won’t help with partial matches unless you split it into fragments and add an order of complexity.

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update: if you really mean "StartsWith", then you could sort the list and place it into an array ; then use Array.BinarySearch to find each item – check by lookup to see if it is a full or partial match.

Update: in the recent .Net, Contains has optional StringComparison parameter , that can be used for case-insensitive comparison, e.g. myString.Contains(s,StringComparison.CurrentCultureIgnoreCase);