CODEWITHSUNDEEP
rexcel
pythh
pythh

Reputation: 61

Calculate sum, mean and variance for several columns of data in R

I'm new to R. The professor asked us to obtain sum, mean and variance for several columns of data which are in Excel form. Now, I want to try to use R to solve them rather than enter the formula in Excel and drag. I have imported the data into R and they are correctly displayed. I can use the commands sum () and sd () and var () for EACH column.

My question is: is there a way to let R display the sum, sd, and variance for each column at the same time? (Rather than calculating these again and again for each column).

I mean something like colSum(col1, col2, col3,...) and the line just shows the sum for each column.

Upvotes: 3

Views: 27075

Answers (2)

s_baldur
s_baldur

Reputation: 33488

More generally you would do something like:

sapply(data, sum)
sapply(data, var)
sapply(data, sd)

Or in one line as suggested by Agile Bean:

sapply(data, function(x) c(sum=sum(x), var=var(x), sd=sd(x)))

Upvotes: 11

pythh
pythh

Reputation: 61

I just figured it out. Basically I need to use colSums() and colMeans(). For example, colSums (,data[2:5]). This means we can calculate the sum for each column from column 2 to column 5.

Upvotes: 3

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