R will give you this warning if you attempt to pass a multi-element vector to a function which can operate on only one logical element. Your vector is too much for that function to handle, so only 1 element from your vector will be used.
Why Does This Error Occur?
The “condition has length > 1 and only the first element will be used” error is most commonly thrown when you pass a multi-element vector to a single variable function such as if () or else(). Since these functions can only address a single element at a time, only the first element is used and this warning will be shown.
I will note that R is at least attempting to handle the exception and keep moving forward with the program, rather than the more traditional “halt and catch fire” behavior which base R prefers to engage in.
How Do I Fix This Error?
You will need to rewrite the offending function so it can operate against a vector rather than a single value. Take look at either sapply() or ifelse(). The details of a solution will need to be based on the specifics of your function… Hopefully you already know how to write a function in rstudio, so it should be a relatively easy fix. You just need to use a function that can accept a vector with multiple elements, or if you’d rather trim your vector down to a single element I suppose you could do that as well.
Error: the condition has length > 1 and only the first element will be used.
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