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Xtrct-methods Methods for "[": Extraction or Subsetting in Package 'Matrix'

Description

Methods for "[", i.e., extraction or subsetting mostly of matrices, in package Matrix.

Methods

There are more than these:

x = "Matrix", i = "missing", j = "missing", drop= "ANY"

...

x = "Matrix", i = "numeric", j = "missing", drop= "missing"

...

x = "Matrix", i = "missing", j = "numeric", drop= "missing"

...

x = "dsparseMatrix", i = "missing", j = "numeric", drop= "logical"

...

x = "dsparseMatrix", i = "numeric", j = "missing", drop= "logical"

...

x = "dsparseMatrix", i = "numeric", j = "numeric", drop= "logical"

...

See Also

[<–methods for subassignment to "Matrix" objects. Extract about the standard extraction.

Examples

str(m <- Matrix(round(rnorm(7*4),2), nrow = 7))
stopifnot(identical(m, m[]))
m[2, 3]   # simple number
m[2, 3:4] # simple numeric of length 2
m[2, 3:4, drop=FALSE] # sub matrix of class 'dgeMatrix'
## rows or columns only:
m[1,]     # first row, as simple numeric vector
m[,1:2]   # sub matrix of first two columns

showMethods("[", inherited = FALSE)