read.zoo {zoo} | R Documentation |
read.zoo
and write.zoo
are convenience functions for reading
and writing "zoo"
series from/to text files. They are convenience
interfaces to read.table
and write.table
, respectively.
read.zoo(file, format = "", tz = "", FUN = NULL, regular = FALSE, index.column = 1, ...) write.zoo(x, file = "", index.name = "Index", row.names = FALSE, col.names = NULL, ...)
file |
character giving the name of the file which the data
are to be read from/written to. See read.table and
write.table for more information. |
format |
date format argument passed to as.Date.character . |
tz |
time zone argument passed to as.POSIXct . |
FUN |
a function for computing the index from the first column of the data. See details. |
regular |
logical. Should the series be coerced to class "zooreg"
(if the series is regular)? |
index.column |
integer. The column of the data frame in which the index/time is stored. |
x |
a "zoo" object. |
index.name |
character with name of the index column in the written data file. |
row.names |
logical. Should row names be written? Default is FALSE
because the row names are just character representations of the index. |
col.names |
logical. Should column names be written? Default is to
write column names only if x has column names. |
... |
further arguments passed to read.table or
write.table , respectively. |
read.zoo
is a convenience function which should make it easier
to read data from a text file and turn it into a "zoo"
series
immediately. read.zoo
reads the data file via read.table(file, ...)
.
The column index.column
(by default the first) of the resulting data is
interpreted to be the index/time, the remaining columns the corresponding data.
(If the file only has only column then that is assumed to be the data column and
1, 2, ...
are used for the index.) To assign the appropriate class
to the index, FUN
can be specified and is applied to the first column.
By default, read.zoo
uses as.Date(as.character(x), format = format)
if format
is
specified and as.POSIXct(as.character(x), tz = tz)
if tz
is specified; otherwise it tries to guess between "numeric"
,
"Date"
and "POSIXct"
.
If regular
is set to TRUE
and the resulting series has an underlying
regularity, it is coerced to a "zooreg"
series.
write.zoo
is a convenience function for writing "zoo"
series
to text files. It first coerces its argument to a "data.frame"
, adds
a column with the index and then calls write.table
.
read.zoo
returns an object of class "zoo"
(or "zooreg"
).
## Not run: ## turn *numeric* first column into yearmon index ## where number is year + fraction of year represented by month z <- read.zoo("foo.csv", sep = ",", FUN = as.yearmon) ## first column is of form yyyy.mm ## (Here we use format in place of as.character so that final zero ## is not dropped in dates like 2001.10 which as.character would do.) f <- function(x) as.yearmon(format(x, nsmall = 2), " z <- read.zoo("foo.csv", header = TRUE, FUN = f) ## turn *character* first column into Date index z <- read.zoo("foo.tab", format = "%m/%d/%Y") ## End(Not run)