> A     [,1] [,2] [,3] [,4][1,]    1    4    7   10[2,]    2    5    8   11[3,]    3    6    9   12

> as.vector(A) [1]  1  2  3  4  5  6  7  8  9 10 11 12

> as.vector(t(A)) [1]  1  4  7 10  2  5  8 11  3  6  9 12

> dim(A)[1] 3 4> ncol(A)[1] 4> nrow(A)[1] 3> A[1:min(dim(A)),1:min(dim(A))]     [,1] [,2] [,3][1,]    1    4    7[2,]    2    5    8[3,]    3    6    9> as.vector(A[1:min(dim(A)),1:min(dim(A))])[1] 1 2 3 4 5 6 7 8 9

vector                  package:base                   R DocumentationVectorsDescription:     ‘vector’ produces a vector of the given length and mode.     ‘as.vector’, a generic, attempts to coerce its argument into a     vector of mode ‘mode’ (the default is to coerce to whichever     vector mode is most convenient): if the result is atomic all     attributes are removed.     ‘is.vector’ returns ‘TRUE’ if ‘x’ is a vector of the specified     mode having no attributes _other than names_.  It returns ‘FALSE’     otherwise.Usage:     vector(mode = "logical", length = 0)     as.vector(x, mode = "any")     is.vector(x, mode = "any")     Arguments:    mode: character string naming an atomic mode or ‘"list"’ or          ‘"expression"’ or (except for ‘vector’) ‘"any"’.  length: a non-negative integer specifying the desired length.  For a          long vector, i.e., ‘length > .Machine$integer.max’, it has to          be of type ‘"double"’.  Supplying an argument of length other          than one is an error.       x: an R object.Details:     The atomic modes are ‘"logical"’, ‘"integer"’, ‘"numeric"’     (synonym ‘"double"’), ‘"complex"’, ‘"character"’ and ‘"raw"’.     If ‘mode = "any"’, ‘is.vector’ may return ‘TRUE’ for the atomic     modes, ‘list’ and ‘expression’.  For any ‘mode’, it will return     ‘FALSE’ if ‘x’ has any attributes except names.  (This is     incompatible with S.)  On the other hand, ‘as.vector’ removes     _all_ attributes including names for results of atomic mode (but     not those of mode ‘"list"’ nor ‘"expression"’).     Note that factors are _not_ vectors; ‘is.vector’ returns ‘FALSE’     and ‘as.vector’ converts a factor to a character vector for ‘mode     = "any"’.Value:     For ‘vector’, a vector of the given length and mode.  Logical     vector elements are initialized to ‘FALSE’, numeric vector     elements to ‘0’, character vector elements to ‘""’, raw vector     elements to ‘nul’ bytes and list/expression elements to ‘NULL’.     For ‘as.vector’, a vector (atomic or of type list or expression).     All attributes are removed from the result if it is of an atomic     mode, but not in general for a list result.  The default method     handles 24 input types and 12 values of ‘type’: the details of     most coercions are undocumented and subject to change.     For ‘is.vector’, ‘TRUE’ or ‘FALSE’.  ‘is.vector(x, mode =     "numeric")’ can be true for vectors of types ‘"integer"’ or     ‘"double"’ whereas ‘is.vector(x, mode = "double")’ can only be     true for those of type ‘"double"’.Methods for 'as.vector()':     Writers of methods for ‘as.vector’ need to take care to follow the     conventions of the default method.  In particular        ? Argument ‘mode’ can be ‘"any"’, any of the atomic modes,          ‘"list"’, ‘"expression"’, ‘"symbol"’, ‘"pairlist"’ or one of          the aliases ‘"double"’ and ‘"name"’.        ? The return value should be of the appropriate mode.  For          ‘mode = "any"’ this means an atomic vector or list.        ? Attributes should be treated appropriately: in particular          when the result is an atomic vector there should be no          attributes, not even names.        ? ‘is.vector(as.vector(x, m), m)’ should be true for any mode          ‘m’, including the default ‘"any"’.Note:     ‘as.vector’ and ‘is.vector’ are quite distinct from the meaning of     the formal class ‘"vector"’ in the ‘methods’ package, and hence     ‘as(x, "vector")’ and ‘is(x, "vector")’.     Note that ‘as.vector(x)’ is not necessarily a null operation if     ‘is.vector(x)’ is true: any names will be removed from an atomic     vector.     Non-vector ‘mode’s ‘"symbol"’ (synonym ‘"name"’) and ‘"pairlist"’     are accepted but have long been undocumented: they are used to     implement ‘as.name’ and ‘as.pairlist’, and those functions should     preferably be used directly.  None of the description here applies     to those ‘mode’s: see the help for the preferred forms.References:     Becker, R. A., Chambers, J. M. and Wilks, A. R. (1988) _The New S     Language_.  Wadsworth & Brooks/Cole.See Also:     ‘c’, ‘is.numeric’, ‘is.list’, etc.Examples:     df <- data.frame(x = 1:3, y = 5:7)     ## Error:     try(as.vector(data.frame(x = 1:3, y = 5:7), mode = "numeric"))          x <- c(a = 1, b = 2)     is.vector(x)     as.vector(x)     all.equal(x, as.vector(x)) ## FALSE               ###-- All the following are TRUE:     is.list(df)     ! is.vector(df)     ! is.vector(df, mode = "list")          is.vector(list(), mode = "list")