list output truncated - How to expand listed variables with str() in R

You can use the argument list.len:

str(df, list.len=ncol(df))

and if you want to print more observations you could set the argument vec.len, also have a look at ?str for documentation of all arguments.

By using argument list.len one can choose the number of variables in the data frame to list. There are two options:

a) You choose the number of variables that you want to list;

str(df, list.len = 602) # in this case I'm listing 602 variables.

b) You choose to list the total number of variables of the data frame (as mentioned by user1981275);

str(df, list.len = ncol(df))

Check R help for more info

> ?str