Suppress large output to R console - r

Question

How can I make R check whether an object is too large to print in the console? "Too large" here means larger than a user-defined value.
Example: You have a list f_data with two elements f_data$data (a 100MB data.frame) and f_data$info (for instance, a vector). Assume you want to inspect the first few entries of the f_data$data data.frame but you make a mistake and type head(f_data) instead of head(f_data$data). R will try to print the whole content of f_data to the console (which would take forever).
Is there somewhere an option that I can set in order to suppress the output of objects that are larger than let's say 1MB?
Edit: Thank you guys for your help. After implementing the max.rows option I realized that this gives indeed the desired output. BUT the problem that the output takes very long to show up still persists. I will give you a proper example below.
df_nrow=100000
df_ncol=100
#create list with first element being a large data.frame
#second element is a short vector
test_list=list(df=data.frame(matrix(rnorm(df_nrow*df_ncol),nrow=df_nrow,ncol=df_ncol)),
vec=1:110)
#only print the first 100 elements of an object
options(max.print=100)
#head correctly displays the first row of the data.frame
#BUT for some reason the output takes really long to show up in the console (~30sec)
head(test_list)
#let's try to see how long exactly
system.time(head(test_list))
# user system elapsed
# 0 0 0
#well, obviously system.time is not the proper tool to measure this
#the same problem if I just print the object to the console without using head
test_list$df
I assume that R performs some sort of analysis on the object being printed and this is what takes so long.
Edit 2:
As per my comment below, I checked whether the problem persists if I use a matrix instead of a data.frame.
#create list with first element being a large MATRIX
test_list=list(mat=matrix(rnorm(df_nrow*df_ncol),nrow=df_nrow,ncol=df_ncol),vec=1:110)
#no problem
head(test_list)
#no problem
test_list$mat
Could it be that the output to the console is not really efficiently implemented for data.frame objects?

Answer 1

I think there is no such option, but you can check the size of an object with object.size and print it if is lower than a threshold (measure in bytes), for example:
print.small.objects <- function(x, threshold = 1e06, ...)
{
if (object.size(x) < threshold) {
print(x, ...)
} else {
cat(paste("too big object\n"))
print(object.size(x))
}
}

Answer 2

Here's an example that you could adjust up to 100MB. It basically only prints the first 6 rows and 5 columns if the object's size is above 8e5 bytes. You could also turn this into a function and place it in your .Rprofile
> lst <- list(data.frame(replicate(100, rnorm(1000))), 1:10)
> sapply(lst, object.size)
# [1] 810968 88
> lapply(lst, function(x){
if(object.size(x) > 8e5) head(x)[1:5] else x
})
#[[1]]
# X1 X2 X3 X4 X5
#1 0.3398235 -1.7290077 -0.35367971 0.09874918 -0.8562069
#2 0.2318548 -0.3415523 -0.38346083 -0.08333569 -1.1091982
#3 0.0714407 -1.4561768 0.50131914 -0.54899188 0.1652095
#4 -0.5170228 1.7343073 -0.05602883 0.87855313 0.4025590
#5 0.6962212 -0.3179930 0.28016057 1.05414456 -0.5172885
#6 0.9471200 1.4424843 -1.46323827 -0.78004192 -1.3611820
#
#[[2]]
# [1] 1 2 3 4 5 6 7 8 9 10