Average of values in columns in dataframe?

dataframe, mean, r

Solution

If I understood your requirement clearly, following should meet your requirement:

 id<-c(1,2,3)
 val<-c(10,15,20)
 sta<-c("A","B","A")

 df<-data.frame(id,val,sta)

 mean(df$val[df$sta=="A"])

Problem

I want to find the mean across a dataframe of values. For example, if I have the following data: ``` ID Value Status 1 10 A 2 15 B 3 20 A ``` And I want to find the mean of all values with the status A in it. How would I do so? Here is my attempt: ``` dataframe$balance.mean(dataframe$status == 'A') ``` But I keep getting an error that says `Error: attempt to apply non-function`. Can anyone help me out? Thanks!

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