How to calculate mean of data frame in R?

Question

I have a data.frame "nitrates". And I have to calculate the mean of the values. When I use:

mean(nitrates)

it gives me NA with the warning:

Warning message: In mean.default(nitrates) : argument is not numeric or logical: returning NA

I want to calculate the mean of data. How can I do that?

May be this will help you: https://stackoverflow.com/questions/46211779/r-how-to-find-the-mean-of-a-column-in-a-data-frame-that-has-non-numeric-speci/46211986 — Dhrubojyoti Sinha, Aug 27 '20 at 16:38
Try subsetting to the specific column you want in the dataframe using `$`. Something like `mean(nitrates$value)` — nniloc, Aug 27 '20 at 17:16
This would work if it was a matrix, e.g.`mean(as.matrix(mtcars))`. — jay.sf, Aug 27 '20 at 19:14

score 0 · Answer 1 · answered Aug 27 '20 at 18:32

Let say you have a dataframe containing mixed string and numeric columns. Since mean is defined for numeric values, you need to first select numeric columns and then move forward with averaging. I don't have your dataframe, so I provide an example with another dataframe, but you can replace storms with nitrates.

library('dplyr')
data('storms')

# mean for each column
storms %>% select_if(is.numeric) %>% apply(2, mean, na.rm=T)

# mean for each row
storms %>% select_if(is.numeric) %>% apply(1, mean, na.rm=T)

# mean over all elements
storms %>% select_if(is.numeric) %>% as.matrix() %>% mean(na.rm=T)

How to calculate mean of data frame in R?

1 Answers1