[Rcpp-devel] Accessing matrix elements

[Dirk Eddelbuettel]

Hi Michael,

On 14 May 2011 at 18:00, Michael Braun wrote:
| Hi, Rcpp-friends:
| 
| File this post under "rookie mistake, "educational illustration," or "feature request," but I noticed something in accessing elements from Rcpp matrices that I found somewhat curious.  Consider the following code, for which the objective is just to print elements of a matrix.

Rookie mistake -- as 

|     cout << x[i,j] << "  ";  // Accessing element using square brackets

simply will not pass any C++ compiler despite whatever magic pixie Rcpp
sprinkles on top. There is no opeator[] that can take two arguments. So use
the round brackets, and rest assured that all other C++ Matrix classes I know
of do the same (e.g. Armadillo is always a good one to check.

Dirk

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