大型术语文档矩阵/simple_triplet_matrix 的行总和？ {tm包}

Question

所以我有一个非常大的术语文档矩阵:

> class(ph.DTM)
[1] "TermDocumentMatrix"    "simple_triplet_matrix"

> ph.DTM
A term-document matrix (109996 terms, 262811 documents)

Non-/sparse entries: 3705693/28904453063
Sparsity           : 100%
Maximal term length: 191 
Weighting          : term frequency (tf)

如何获得每个术语的 rowSum(频率)？我尝试过:

> apply(ph.DTM, 1, sum)
Error in vector(typeof(x$v), nr * nc) : vector size cannot be NA
In addition: Warning message:
In nr * nc : NAs produced by integer overflow

显然，我知道removeSparseTerms:

ph.DTM2 <- removeSparseTerms(ph.DTM, 0.99999)

这会稍微缩小尺寸:

> ph.DTM2
A term-document matrix (28842 terms, 262811 documents)

Non-/sparse entries: 3612620/7576382242
Sparsity           : 100%
Maximal term length: 24 
Weighting          : term frequency (tf)

但我仍然无法对其应用任何与矩阵相关的函数:

> as.matrix(ph.DTM2)
Error in vector(typeof(x$v), nr * nc) : vector size cannot be NA
In addition: Warning message:
In nr * nc : NAs produced by integer overflow

我怎样才能获得这个对象的简单行总和？谢谢!!

Answer 1

好吧，经过更多的 Google 搜索，我发现了 slam 包，它可以:

ph.DTM3 <- rollup(ph.DTM, 2, na.rm=TRUE, FUN = sum)

这有效。