I'm looking for a function to dump variables and objects, with human readable explanations of their data types. For instance, in php var_dump does this.
$foo = array();
$foo[] = 1;
$foo['moo'] = 2;
var_dump($foo);
Yields:
array(2) {
[0]=>
int(1)
["moo"]=>
int(2)
}
A few examples:
foo <- data.frame(1:12,12:1)
foo ## What's inside?
dput(foo) ## Details on the structure, names, and class
str(foo) ## Gives you a quick look at the variable structure
Output on screen:
foo <- data.frame(1:12,12:1)
foo
X1.12 X12.1
1 1 12
2 2 11
3 3 10
4 4 9
5 5 8
6 6 7
7 7 6
8 8 5
9 9 4
10 10 3
11 11 2
12 12 1
> dput(foo)
structure(list(X1.12 = 1:12, X12.1 = c(12L, 11L, 10L, 9L, 8L,
7L, 6L, 5L, 4L, 3L, 2L, 1L)), .Names = c("X1.12", "X12.1"), row.names = c(NA,
-12L), class = "data.frame")
> str(foo)
'data.frame': 12 obs. of 2 variables:
$ X1.12: int 1 2 3 4 5 6 7 8 9 10 ...
$ X12.1: int 12 11 10 9 8 7 6 5 4 3 ...
Check out the dump command:
> x <- c(8,6,7,5,3,0,9)
> dump("x", "")
x <-
c(8, 6, 7, 5, 3, 0, 9)
Try deparse, for example:
> deparse(1:3)
[1] "1:3"
> deparse(c(5,6))
[1] "c(5, 6)"
> deparse(data.frame(name=c('jack', 'mike')))
[1] "structure(list(name = structure(1:2, .Label = c(\"jack\", \"mike\""
[2] "), class = \"factor\")), .Names = \"name\", row.names = c(NA, -2L"
[3] "), class = \"data.frame\")"
It's better than dump, because dump requires a variable name, and it creates a dump file.
If you don't want to print it directly, but for example put it inside a string with sprintf(fmt, ...) or a variable to use later, then it's better than dput, because dput prints directly.
print is probably the easiest function to use out of the box; most classes provide a customised print. They might not specifically name the type, but will often provide a distinctive form.
Otherwise, you might be able to write custom code to use the class and datatype functions to retrieve the information you want.
