[R] [FORGED] Re: R lappy, sapply or mapply question

Rolf Turner
2015-10-09T23:28:16Z

On 10/10/15 10:56, Adams, Jean wrote:
> You were very close.  Try this.
>
> df <- data.frame(x5=dailyrecord$a, x6 = dailyrecord$e, x7 =
dailyrecord$f)
> apply(df, 1, function(row) fun3(list1, list2, as.list(row)))


There could in general be problems with this approach.  The apply()
function works on *matrices* and if handed a data frame coerces it to a
matrix.  This is (usually!) OK if all columns of the data frame are of
the same type, but the world could end if they are not. It is a good
idea to *start* with a matrix if a matrix is what is required.  And do
not confuse data frames with matrices.  They are very different animals.

cheers,

Rolf Turner

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