CODEWITHSUNDEEP
rlapply
user11493891
user11493891

Reputation: 47

how to implement R lapply on a data frame object

I am very new to R and especially to R apply family functions.

I have a data frame:

df <- data.frame(a=c(1,2,3),b=c(3,4,5))

And tried:

lapply(df$a,sum)

But this doesn't give the sum of the first column of data frame df.

However, this line of code does:

lapply(df,sum)

Is there something that I am doing wrong here?

Upvotes: 1

Views: 39

Answers (1)

akrun
akrun

Reputation: 886948

For multiple columns, use colSums

colSums(df, na.rm = TRUE)

and single column, it would be

sum(df$a, na.rm = TRUE)

If we loop over a vector, each element of the list have a length of 1, thus the sum would be the element itself

Upvotes: 1

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