Mean vector of iris dataset by columns

Question

I want a mean vector of the iris dataset such that the first element in the vector is the mean of the first column, the second is the mean of the second column etc..

My code is:

data("iris")

mean(iris[,1:4])

I get the message:

Warning message:
In mean.default(iris[, 1:4]) :
  argument is not numeric or logical: returning NA

If I try to calculate the mean of each collumn with mean(iris[,1]), mean(iris[,2])... I have no problem but if I do the mean(iris[,1:4]) it returns NA

Does this answer your question? [Grouping functions (tapply, by, aggregate) and the \*apply family](https://stackoverflow.com/questions/3505701/grouping-functions-tapply-by-aggregate-and-the-apply-family) — AlexB, Jan 10 '22 at 13:05
Answered at https://stackoverflow.com/questions/30941504/calculate-mean-for-multiple-columns-in-data-frame — jakekraska, Jan 10 '22 at 13:06

score 1 · Accepted Answer · answered Jan 10 '22 at 12:58

You need to use colMeans to get the mean values for each column/list (a data.frame is a set of lists). mean only works on single vectors.

colMeans(iris[,1:4])
Sepal.Length  Sepal.Width Petal.Length  Petal.Width 
    5.843333     3.057333     3.758000     1.199333

Mean vector of iris dataset by columns

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