nrow | R Documentation |
nrow
and ncol
return the number of rows or columns
present in x
.
NCOL
and NROW
do the same treating a vector as
1-column matrix, even a 0-length vector, compatibly with
as.matrix()
or cbind()
, see the example.
nrow(x) ncol(x) NCOL(x) NROW(x)
x |
a vector, array, data frame, or |
an integer
of length 1 or NULL
, the
latter only for ncol
and nrow
.
Becker, R. A., Chambers, J. M. and Wilks, A. R. (1988)
The New S Language.
Wadsworth & Brooks/Cole (ncol
and nrow
.)
dim
which returns all dimensions, and
length
which gives a number (a ‘count’) also in cases where
dim()
is NULL
, and hence nrow()
and ncol()
return NULL
;
array
, matrix
.
ma <- matrix(1:12, 3, 4) nrow(ma) # 3 ncol(ma) # 4 ncol(array(1:24, dim = 2:4)) # 3, the second dimension NCOL(1:12) # 1 NROW(1:12) # 12, the length() of the vector ## as.matrix() produces 1-column matrices from 0-length vectors, ## and so does cbind() : dim(as.matrix(numeric())) # 0 1 dim( cbind(numeric())) # ditto ## consequently, NCOL(.) gives 1, too : NCOL(numeric()) # 1 and hence NCOL(NULL) # 1
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