| head {utils} | R Documentation |
Returns the first or last parts of a vector, matrix, table, data frame
or function. Since head() and tail() are generic
functions, they may also have been extended to other classes.
head(x, ...) ## Default S3 method: head(x, n = 6, ...) ## S3 method for class 'data.frame': head(x, n = 6, ...) ## S3 method for class 'matrix': head(x, n = 6, ...) ## S3 method for class 'ftable': head(x, n = 6, ...) ## S3 method for class 'table': head(x, n = 6, ...) ## S3 method for class 'function': head(x, n = 6, ...) tail(x, ...) ## Default S3 method: tail(x, n = 6, ...) ## S3 method for class 'data.frame': tail(x, n = 6, ...) ## S3 method for class 'matrix': tail(x, n = 6, addrownums = TRUE, ...) ## S3 method for class 'ftable': tail(x, n = 6, addrownums = FALSE, ...) ## S3 method for class 'table': tail(x, n = 6, addrownums = TRUE, ...) ## S3 method for class 'function': tail(x, n = 6, ...)
x |
an object |
n |
a single integer. If positive, size for the resulting
object: number of elements for a vector (including lists), rows for
a matrix or data frame or lines for a function. If negative, all but
the n last/first number of elements of x. |
addrownums |
if there are no row names, create them from the row numbers. |
... |
arguments to be passed to or from other methods. |
For matrices, 2-dim tables and data frames, head() (tail()) returns
the first (last) n rows when n > 0 or all but the
last (first) n rows when n < 0. head.matrix() and
tail.matrix() are exported. For functions, the
lines of the deparsed function are returned as character strings.
If a matrix has no row names, then tail() will add row names of
the form "[n,]" to the result, so that it looks similar to the
last lines of x when printed. Setting addrownums =
FALSE suppresses this behaviour.
An object (usually) like x but generally smaller. For
ftable objects x, a transformed format(x).
Patrick Burns, improved and corrected by R-Core. Negative argument added by Vincent Goulet.
head(letters) head(letters, n = -6) head(freeny.x, n = 10) head(freeny.y) tail(letters) tail(letters, n = -6) tail(freeny.x) tail(freeny.y) tail(library) head(ftable(Titanic))