List

Basic facilities for working with an R list.

Constructing

this(string code)

Executes code inside R and stores the result as a List.

this(List x)

Puts a copy of x in a new list.

this(long n)

Allocates a new list with n elements. Not important in practice, because R will automatically resize the list as necessary.

this(Robj obj)

Mostly for internal use.

this(RData rd)

Mostly for internal use.

Indexing

You can index by name or number.

x["integer element"] = 3;
x[2] = "Third element of the list";

Note that when indexing like this, the return type is unknown, so you always get an element of type RData. To specify the type, as you’ll usually want to do, use the as method:

auto j = x["integer element"].as!int;
auto m = x[3].as!Matrix;

Getting multiple elements

You can do the usual slicing. It returns a new list holding the elements.

List y = x[0..3]; // First three elements of x
List z = x[2..$]; // Dollar operator works

Alternatively, if you want to grab multiple nonconsecutive elements, or multiple elements by name, you can do this:

List y = x[[0, 1, 2]];
List z = x[["One Element's Name", "Another Element's Name"]];

Duplicating

You can use dup to make a copy:

List y = x.dup();

Setting elements

Just as you can get elements by name or index number, you can also set elements that way.

x["Item Name"] = rnorm(100);
y[4] = 6.2;

Names

You can get a string[] holding all names in the list by calling names:

x["Random"] = rnorm(100);
x["Not Random"] = 6.2;
writeln(x.names);

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