`tsp`

returns the `tsp`

attribute (or `NULL`

).
It is included for compatibility with S version 2. `tsp<-`

sets the `tsp`

attribute. `hasTsp`

ensures `x`

has a
`tsp`

attribute, by adding one if needed.

```
tsp(x)
tsp(x) <- value
hasTsp(x)
```

x

a vector or matrix or univariate or multivariate time-series.

value

a numeric vector of length 3 or `NULL`

.

An object which differs from `x`

only in the `tsp`

attribute
(unless `NULL`

is assigned).

`hasTsp`

adds, if needed, an attribute with a start time and
frequency of 1 and end time `NROW(x)`

.

The `tsp`

attribute gives the start time *in time units*,
the end time and the frequency (the number of observations per unit of
time, e.g.12 for a monthly series).

Assignments are checked for consistency.

Assigning `NULL`

which removes the `tsp`

attribute
*and* any `"ts"`

(or `"mts"`

) class of `x`

.

Becker, R. A., Chambers, J. M. and Wilks, A. R. (1988)
*The New S Language*.
Wadsworth & Brooks/Cole.