yearmon {zoo} | R Documentation |

## An Index Class for Monthly Data

### Description

`"yearmon"`

is a class for representing monthly data.

### Usage

yearmon(x)

### Arguments

`x` |
numeric (interpreted as being “in years”). |

### Details

The yearmon class is used to represent monthly data. Internally it holds
the data as year plus 0 for January, 1/12 for February, 2/12 for March
and so on in order that its internal representation is the same as
`ts`

class with `frequency = 12`

. If `x`

is not in this
format it is rounded via `floor(12*x + .0001)/12`

.

There are coercion methods available for various classes including:
default coercion to `"yearmon"`

(which coerces to `"numeric"`

first)
and coercion from `"yearmon"`

to `"Date"`

(see below), `"POSIXct"`

,
`"POSIXlt"`

, `"numeric"`

, `"character"`

.

### Value

Returns its argument converted to class `yearmon`

.

### See Also

`yearqtr`

, `zoo`

, `zooreg`

, `ts`

### Examples

x <- yearmon(2000 + seq(0, 23)/12)
x
# returned Date is the fraction of the way through
# the period given by frac (= 0 by default)
as.Date(x)
as.Date(x, frac = 1)
as.POSIXct(x)
z <- zoo(rnorm(24), x, frequency = 12)
z
as.ts(z)

[Package

*zoo* version 1.0-5

Index]