Exercise

safely() replace with NA

If you map() over a list, and one of the elements does not have the right data type, you will not get the output you expect. Perhaps you are trying to do a mathematical operation on each element, and it turns out one of the elements is a character - it simply won't work.

If you have a very large list, figuring out where things went wrong, and what exactly went wrong can be hard. That is where safely() comes in; it shows you both your results and where the errors occurred in your map() call.

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Use safely() with log. This will fail to work on non-numeric arguments, so we'll pipe it into transpose() to put the results first.