data.frame

R Base 3.6.2

The function data.frame() creates data frames, tightly coupled collections of variables which share many of the properties of matrices and of lists, used as the fundamental data structure by most of R's modeling software.

Syntax

data.frame(&#8230;, row.names = NULL, check.rows = FALSE,
           check.names = TRUE, fix.empty.names = TRUE,
           stringsAsFactors = default.stringsAsFactors())<p></p><p>default.stringsAsFactors()</p>

Arguments

Parameter	Description
`…`	these arguments are of either the form value or tag = value. Component names are created based on the tag (if present) or the deparsed argument itself.
`row.names`	NULL or a single integer or character string specifying a column to be used as row names, or a character or integer vector giving the row names for the data frame.
`check.rows`	if TRUE then the rows are checked for consistency of length and names.
`check.names`	logical. If TRUE then the names of the variables in the data frame are checked to ensure that they are syntactically valid variable names and are not duplicated. If necessary they are adjusted (by make.names) so that they are.
`fix.empty.names`	logical indicating if arguments which are “unnamed” (in the sense of not being formally called as someName = arg) get an automatically constructed name or rather name "". Needs to be set to FALSE even when check.names is false if "" names should be kept.
`stringsAsFactors`	logical: should character vectors be converted to factors? The ‘factory-fresh’ default is TRUE, but this can be changed by setting options(stringsAsFactors = FALSE).

Return Value

A data frame, a matrix-like structure whose columns may be of differing types (numeric, logical, factor and character and so on). How the names of the data frame are created is complex, and the rest of this paragraph is only the basic story. If the arguments are all named and simple objects (not lists, matrices of data frames) then the argument names give the column names. For an unnamed simple argument, a deparsed version of the argument is used as the name (with an enclosing I(...) removed). F

Details

A data frame is a list of variables of the same number of rows with unique row names, given class "data.frame". If no variables are included, the row names determine the number of rows. The column names should be non-empty, and attempts to use empty names will have unsupported results. Duplicate column names are allowed, but you need to use check.names = FALSE for data.frame to generate such a data frame. However, not all operations on data frames will preserve duplicated column names: for example matrix-like subsetting will force column names in the result to be unique. data.frame converts each of its arguments to a data frame by calling as.data.frame(optional = TRUE). As that is a generic function, methods can be written to change the behaviour of arguments according to their classes: R

Examples

Example

# NOT RUN {
L3 <- LETTERS[1:3]
fac <- sample(L3, 10, replace = TRUE)
(d <- data.frame(x = 1, y = 1:10, fac = fac))
## The "same" with automatic column names:
data.frame(1, 1:10, sample(L3, 10, replace = TRUE))

is.data.frame(d)

## do not convert to factor, using I() :
(dd <- cbind(d, char = I(letters[1:10])))
rbind(class = sapply(dd, class), mode = sapply(dd, mode))

stopifnot(1:10 == row.names(d))  # {coercion}

(d0  <- d[, FALSE])   # data frame with 0 columns and 10 rows
(d.0 <- d[FALSE, ])   # <0 rows> data frame  (3 named cols)
(d00 <- d0[FALSE, ])  # data frame with 0 columns and 0 rows
# }