R 本身内容多样丰富，有此基本的，在使用中严格标准化，如：data.frame ，仔细读完下文，就不会有问题：
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 comes with many such methods.
Character variables passed to data.frame are converted to factor columns unless protected by I or
argument stringsAsFactors is false. If a list or data frame or matrix is passed to data.frame it
is as if each component or column had been passed as a separate argument (except for matrices of
class "model.matrix" and those protected by I).
Objects passed to data.frame should have the same number of rows, but atomic vectors, factors and
character vectors protected by I will be recycled a whole number of times if necessary (including
as elements of list arguments).
If row names are not supplied in the call to data.frame, the row names are taken from the first
component that has suitable names, for example a named vector or a matrix with rownames or a
data frame. (If that component is subsequently recycled, the names are discarded with a warning.)
If row.names was supplied as NULL or no suitable component was found the row names are the
integer sequence starting at one (and such row names are considered to be ‘automatic’, and not
preserved by as.matrix).
If row names are supplied of length one and the data frame has a single row, the row.names is taken
to specify the row names and not a column (by name or number).
Names are removed from vector inputs not protected by I.
default.stringsAsFactors is a utility that takes getOption("stringsAsFactors") and ensures
the result is TRUE or FALSE (or throws an error if the value is not NULL).
扫码加好友，拉您进群
全部版块
我的主页
收藏
