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copied!<p>There are some built-in functions that can clean up your code. And I think you're not leveraging the full power of regular expressions.</p> <p>The blaring issue here is <code>strsplit</code>. Comparing the equality of things character-by-character is inefficient when you have regular expressions. The pattern here uses the square bracket notation to filter for the characters you want. <code>*</code> is for any number of repeats (including zero), while the <code>^</code> and <code>$</code> symbols represent the beginning and end of the line so that there is nothing else there. <code>nchar(word)</code> is the same as <code>length(chars)</code>. Changing <code>&&</code> to <code>&</code> makes the function vectorized so you can input a vector of strings and get a logical vector as output.</p> <pre><code>check.pattern.2 = function(word, min.size = 2) { word = trim(word) grepl(paste0("^[a-z!.?]*$"),word) & nchar(word) >= min.size } check.pattern.2(c(" d ","!hello ","nA!"," asdf.!"," d d ")) #[1] FALSE TRUE FALSE TRUE FALSE </code></pre> <p>Next, using curly braces for number of repetitions and some <code>paste0</code>, the pattern can use your min.size:</p> <pre><code>check.pattern.3 = function(word, min.size = 2) { word = trim(word) grepl(paste0("^[a-z!.?]{",min.size,",}$"),word) } check.pattern.3(c(" d ","!hello ","nA!"," asdf.!"," d d ")) #[1] FALSE TRUE FALSE TRUE FALSE </code></pre> <p>Finally, you can internalize the regex from <code>trim</code>:</p> <pre><code>check.pattern.4 = function(word, min.size = 2) { grepl(paste0("^\\s*[a-z!.?]{",min.size,",}\\s*$"),word) } check.pattern.4(c(" d ","!hello ","nA!"," asdf.!"," d d ")) #[1] FALSE TRUE FALSE TRUE FALSE </code></pre>

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