nrow
Get the Number of Rows or Columns of an Array or Matrix

### Description

Returns the number of rows or columns of an array or matrix.

### Usage

    nrow(x)
    NROW(x)
    ncol(x)
    NCOL(x)

### Arguments

x | any object.

### Details

These functions are generic because they are based on the dim function, which is generic.
Value

nrow | returns the first dimension of an array or matrix. If there are no dimensions, it returns NULL.
ncol | returns the second dimension of an array or matrix. If there is no second dimension, it returns NULL.
NROW | returns the first dimension of an array or matrix. If there are no dimensions, it returns the length.
NCOL | returns the second dimension of an array or matrix. If there is no second dimension, it returns 1.

References
Becker, R. A., Chambers, J. M., and Wilks, A. R. 1988. The New S Language. Pacific Grove, CA: Wadsworth & Brooks/Cole Advanced Books and Software. (ncol and nrow.)
See Also
dim, length, array, data.frame
Examples

    m <- matrix(1:6, 3, 2)
    nrow(m) # 3
    NROW(m) # 3
    ncol(m) # 2
    NCOL(m) # 2
    nrow(1:4) # NULL
    NROW(1:4) # 4
    ncol(1:4) # NULL
    NCOL(1:4) # 1

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