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copied!<p>You might want to change your <code>getNumberInfo</code> function to return a list rather than a vector, so that the values can have different types. As it is, they're all being cast to strings, which probably isn't what you want for <code>logX</code>.</p> <pre><code>getNumberInfo <- function(x) { if(x %% 2 ==0) evenness = "Even" else evenness="Odd" if(x > 0) positivity = "Positive" else positivity = "NonPositive" if (positivity == "Positive") logX = log(x) else logX=NA list(evenness,positivity,logX) } </code></pre> <p>Furthermore, you can use the names to a somewhat better effect so that you don't have to repeat them:</p> <pre><code>getNumberInfo <- function(x) { list(evenness = if(x %% 2 ==0) "Even" else "Odd", positivity = if(x > 0) "Positive" else "NonPositive", logX = if(x > 0) log(x) else NA) } </code></pre> <p>Then the solution becomes simple:</p> <pre><code>> cbind(myDF, t(sapply(myDF$Value, getNumberInfo))) Value evenness positivity logX 1 -2 Even NonPositive NA 2 -1 Odd NonPositive NA 3 0 Even NonPositive NA 4 1 Odd Positive 0 5 2 Even Positive 0.6931472 </code></pre> <p>Finally, if you use <code>ifelse</code> (which can work on vectors) instead of <code>if</code>, it gets even simpler because you don't have to call <code>apply</code>:</p> <pre><code>getNumberInfo <- function(x) { list(evenness = ifelse(x %% 2 ==0, "Even", "Odd"), positivity = ifelse(x > 0, "Positive", "NonPositive"), logX = ifelse(x > 0, log(x), NA)) } > cbind(myDF, getNumberInfo(myDF$Value)) Value evenness positivity logX 1 -2 Even NonPositive NA 2 -1 Odd NonPositive NA 3 0 Even NonPositive NA 4 1 Odd Positive 0.0000000 5 2 Even Positive 0.6931472 </code></pre> <p>That last solution emits a warning, because it's actually computing the log of every element, not just those with <code>x>0</code>. Not sure the most elegant way to deal with that.</p>

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