Is string in array?

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What would be the best way to look in a string[] to see if it contains a element. This was my first shot at it. But perhaps there is something that I am overlooking. The array size will be no larger than 200 elements.

bool isStringInArray(string[] strArray, string key)
{
    for (int i = 0; i <= strArray.Length - 1; i++)
        if (strArray[i] == key)
            return true;
    return false;
}
10 Answers

Just use the already built-in Contains() method:

using System.Linq;

//...

string[] array = { "foo", "bar" };
if (array.Contains("foo")) {
    //...
}

You're simply after the Array.Exists function (or the Contains extension method if you're using .NET 3.5, which is slightly more convenient).

Linq (for s&g's):

var test = "This is the string I'm looking for";
var found = strArray.Any(x=>x == test);

or, depending on requirements

var found = strArray.Any(
    x=>x.Equals(test, StringComparison.OrdinalIgnoreCase));

Arrays are, in general, a poor data structure to use if you want to ask if a particular object is in the collection or not.

If you'll be running this search frequently, it might be worth it to use a Dictionary<string, something> rather than an array. Lookups in a Dictionary are O(1) (constant-time), while searching through the array is O(N) (takes time proportional to the length of the array).

Even if the array is only 200 items at most, if you do a lot of these searches, the Dictionary will likely be faster.

You can also use LINQ to iterate over the array. or you can use the Find method which takes a delegate to search for it. However I think the find method is a bit more expensive then just looping through.

This is quicker than iterating through the array manually:

static bool isStringInArray(string[] strArray, string key)
    {

        if (strArray.Contains(key))
            return true;
        return false;
    }
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