function - Issue with NA values in R -

i feel should easy, have looked x internet, keep getting error messages. have done plenty of analytics in past new r , programming.

i have pretty basic function calculate means x columns of data:

columnmean <-function(y){   nc <- ncol(y)   means <- numeric(nc)   for(i in 1:nc) {     means[i] <- mean(y[,i])   }     means  } 

i'm in rstudio , testing using included 'airquality' dataset. when load aq dataset , run function:

data("airquality") columnmean(airquality) 

i back:

na na 9.957516 77.882353 6.993464 15.803922

because first 2 variables in aq have nas in them. k, cool. want suppress nas such r ignore them , run function anyway.

i reading can specify na.rm=true, like:

columnmean(airquality, na.rm = true) 

but when this, error message saying:

"error in columnmean(airquality, na.rm = true) : unused argument (na.rm = true)"

i'm reading on place need include na.rm = true , function run , ignore na values...but keep getting error. have tried use = "complete" , else can find.

two caveats:

i know can create vector is.na , subset data, don't want step, want run function , ignore missing data.

i know can specify in function ignore or not ignore, i'd way choose ignore/not ignore on fly, on action action basis, rather having part of function itself.

help appreciated. thank you, everyone.

we can include na.rm = true in mean

columnmean <-function(y){   nc <- ncol(y)   means <- numeric(nc)   for(i in 1:nc) {     means[i] <- mean(y[,i], na.rm = true)   }    means  } 

---

if need use na.rm argument false , other times true, specify in argument of 'columnmean'

columnmean <-function(y, ...){     nc <- ncol(y)   means <- numeric(nc)    for(i in 1:nc) {      means[i] <- mean(y[,i], ...)    }    means    }  columnmean(df1, na.rm = true) #[1] 1.5000000 0.3333333  columnmean(df1, na.rm = false) #[1] 1.5  na 

data

 df1 <- structure(list(num = c(1l, 1l, 2l, 2l), x1 = c(1l, na, 0l, 0l  )), .names = c("num", "x1"), row.names = c(na, -4l), class = "data.frame")