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| 6 |
\name{Extract.data.frame}
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6 |
\name{Extract.data.frame}
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| 7 |
\alias{[.data.frame}
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7 |
\alias{[.data.frame}
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\alias{[[.data.frame}
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8 |
\alias{[[.data.frame}
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| 9 |
\alias{[<-.data.frame}
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9 |
\alias{[<-.data.frame}
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\alias{[[<-.data.frame}
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\alias{[[<-.data.frame}
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| - |
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\alias{$.data.frame}
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| 11 |
\alias{$<-.data.frame}
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\alias{$<-.data.frame}
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\title{Extract or Replace Parts of a Data Frame}
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\title{Extract or Replace Parts of a Data Frame}
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\description{
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14 |
\description{
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| 14 |
Extract or replace subsets of data frames.
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Extract or replace subsets of data frames.
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}
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}
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\usage{
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17 |
\usage{
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| 17 |
\method{[}{data.frame}(x, i, j, drop = )
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\method{[}{data.frame}(x, i, j, drop = )
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\method{[}{data.frame}(x, i, j) <- value
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\method{[}{data.frame}(x, i, j) <- value
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\method{[[}{data.frame}(x, ..., exact = TRUE)
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20 |
\method{[[}{data.frame}(x, ..., exact = TRUE)
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\method{[[}{data.frame}(x, i, j) <- value
|
21 |
\method{[[}{data.frame}(x, i, j) <- value
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| - |
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\method{$}{data.frame}(x, name)
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\method{$}{data.frame}(x, name) <- value
|
23 |
\method{$}{data.frame}(x, name) <- value
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| 22 |
}
|
24 |
}
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| 23 |
\arguments{
|
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\arguments{
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| 24 |
\item{x}{data frame.}
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\item{x}{data frame.}
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|
27 |
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| 48 |
Data frames can be indexed in several modes. When \code{[} and
|
50 |
Data frames can be indexed in several modes. When \code{[} and
|
| 49 |
\code{[[} are used with a single vector index (\code{x[i]} or
|
51 |
\code{[[} are used with a single vector index (\code{x[i]} or
|
| 50 |
\code{x[[i]]}), they index the data frame as if it were a list. In
|
52 |
\code{x[[i]]}), they index the data frame as if it were a list. In
|
| 51 |
this usage a \code{drop} argument is ignored, with a warning.
|
53 |
this usage a \code{drop} argument is ignored, with a warning.
|
| 52 |
|
54 |
|
| 53 |
There is no \code{data.frame} method for \code{$}, so \code{x$name}
|
55 |
The \code{data.frame} method for \code{$}, treats \code{x} as a
|
| 54 |
uses the default method which treats \code{x} as a list. There is a
|
56 |
list, except that (as of R-3.1.0) partial matching of \code{name} to
|
| 55 |
replacement method which checks \code{value} for the correct number
|
57 |
the names of \code{x} will generate a warning; this may become an
|
| 56 |
of rows, and replicates it if necessary.
|
58 |
error in future versions. The replacement method checks
|
| - |
|
59 |
\code{value} for the correct number of rows, and replicates it if
|
| - |
|
60 |
necessary.
|
| 57 |
|
61 |
|
| 58 |
When \code{[} and \code{[[} are used with two indices (\code{x[i, j]}
|
62 |
When \code{[} and \code{[[} are used with two indices (\code{x[i, j]}
|
| 59 |
and \code{x[[i, j]]}) they act like indexing a matrix: \code{[[} can
|
63 |
and \code{x[[i, j]]}) they act like indexing a matrix: \code{[[} can
|
| 60 |
only be used to select one element. Note that for each selected
|
64 |
only be used to select one element. Note that for each selected
|
| 61 |
column, \code{xj} say, typically (if it is not matrix-like), the
|
65 |
column, \code{xj} say, typically (if it is not matrix-like), the
|
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