Methods

This help page gives an overview of the methods available in 'squarebrackets'.

Main Methods

The main methods of 'squarebrackets' use the naming convention A_B:
A tells you on what kind of object and what kind of indices the method operates on;
B tells you what operation is performed.

For the A part, the following is available:

• i_: operates on subsets of atomic objects by (flat/linear) indices.

• i2_: operates on subsets of recursive objects by (flat/linear) indices.

• ss_: operates on subsets of atomic objects by (dimensional) subscripts.

• ss2_: operates on subsets of recursive objects by (dimensional) subscripts.

• slice_: uses index-less, sequence-based, and efficient operations on mutatomic objects.

• slicev_: uses index-less, value-based and efficient operations on mutatomic objects.
  
  

For the B part, the following is available:

• _x: extract, exchange, or duplicate (if applicable) subsets.

• _wo: returns the original object without the provided subsets.

• _mod: modify subsets and return copy.

• _set: modify subsets using pass-by-reference semantics.
  
  

To illustrate, let's take the methods used for extracting subsets (_x).

When y is atomic, the following holds (roughly speaking):

• i_x(y, i) corresponds to y[i]

• ss_x(y, n(i, k), c(1, 3)) corresponds to y[i, , k]
  
  

When y is a list (i.e. recursive), the following holds (roughly speaking):

• i2_x(y, i) corresponds to y[i] or y[[i]] (depending on the arguments given in i2_x())

• ss2_x(y, n(i, k), c(1, 3)) corresponds to y[i, , k] or y[[i, , k]] (depending on the arguments given in ss2_x())
  
  

Other Methods

Besides the main methods, 'squarebrackets' provides some additional methods that do not neatly fit into the above methods.

First, there is the lst_ set of methods, which deal with sub-set operations that are only relevant for (nested) lists, but not for the other types of supported objects.

Second, there is idx method, which works on both recursive and non-recursive objects, and transforms/translates indices to be used in R's default copy-on-modify semantics.

Finally, there are the sb_ and sb2_ sets of methods, which cover miscellaneous operations for atomic and recursive objects, respectively.

Finding the Appropriate Help Pages

With knowledge of the naming convention of the main methods, one can easily find out information about a particular method by usign the ? operator.
So to find out about modifying recursive objects by subscripts using Pass-by-Reference semantics, type in:
?ss2_set