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copied!<p>The obligatory Regex answer:</p> <pre><code>Regex re = new Regex(@"(\w){50,}"); re.IsMatch(input); </code></pre> <p>PS: While I tend to stay away from Regex, I feel in this case a Regex is simpler and faster.</p> <p><strong>Edit after @jimmy_keen's experiment</strong></p> <p>@jimmy_keen - Thanks for that.</p> <p>I removed the group, since it was not really needed and the time taken was much lesser for Regex, below is the output for compiled:</p> <p>Changed Regex:</p> <pre><code>Regex regex = new Regex(@"\w{50,}", RegexOptions.Compiled); </code></pre> <p>Output:</p> <blockquote> <p>LINQ [noLongWords], 1000000 iterations. Result = False: 725 ms</p> <p>LINQ [oneLongWordAtEnd], 1000000 iterations. Result = True: 760 ms</p> <p>LINQ [oneLongWordAtBegining], 1000000 iterations. Result = True: 651 ms</p> <p>LINQ [manyLongWordsEverywhere], 1000000 iterations. Result = True: 2107 ms</p> <p>Regex [noLongWords], 1000000 iterations. Result = False: 2773 ms</p> <p>Regex [oneLongWordAtEnd], 1000000 iterations. Result = True: 7217 ms</p> <p>Regex [oneLongWordAtBegining], 1000000 iterations. Result = True: 3279 ms</p> <p>Regex [manyLongWordsEverywhere], 1000000 iterations. Result = True: 3283 ms</p> <p>DONE</p> </blockquote> <p>The regex being slower than LINQ in this situation was sort of surprising for, but maybe not, because I have been burnt by regexes many times. They are a great tool, but very heavy. In this case, I was thinking the regex would be able to come slightly ahead of LINQ, but that is not to be.</p> <p>A slightly more complex, but similar regex outperforms LINQ in many long words case:</p> <pre><code>Regex regex = new Regex(@"[A-Za-z0-9]{50,}", RegexOptions.Compiled); </code></pre> <blockquote> <p>LINQ [noLongWords], 1000000 iterations. Result = False: 611 ms</p> <p>LINQ [oneLongWordAtEnd], 1000000 iterations. Result = True: 642 ms </p> <p>LINQ [oneLongWordAtBegining], 1000000 iterations. Result = True: 549 ms </p> <p>LINQ [manyLongWordsEverywhere], 1000000 iterations. Result = True: 1914 ms</p> <p>Regex [noLongWords], 1000000 iterations. Result = False: 2085 ms</p> <p>Regex [oneLongWordAtEnd], 1000000 iterations. Result = True: 4147 ms</p> <p>Regex [oneLongWordAtBegining], 1000000 iterations. Result = True: 1569 ms</p> <p>Regex [manyLongWordsEverywhere], 1000000 iterations. Result = True: 1580 ms </p> <p>DONE</p> </blockquote> <p><strong>But I still believe that the simplicty of the regex and that the performance difference starts to be seen at 100,000 iterations or more, regex is still the best solution here</strong></p>

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