CODEWITHSUNDEEP
rsumdata.table
Soheil
Soheil

Reputation: 974

How to find the mean of non-zero values by group?

I want to find the mean of non-zero values by group for multiple columns:

mydata<- data[, lapply(.SD, function(x) mean(x, na.rm=TRUE)), by=group, 
                        .SDcols=c("col1", "col2")]

What should I add to the above code?

Upvotes: 1

Views: 1538

Answers (1)

akrun
akrun

Reputation: 887691

We subset the elements that are not 0 (x[x!=0]) for each column specified in .SDcols and get the mean by 'group'

data[, lapply(.SD, function(x) mean(x[x!=0], na.rm=TRUE)), by =group,
                 .SDcols= c('col1', 'col2')]

Upvotes: 3

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