在dplyr中添加add_rownames的相反函数 [英] opposite function to add_rownames in dplyr

问题描述

作为中间步骤，我将生成一列数据作为字符串，其余数字是数字。我想将其转换为矩阵，但首先我必须将该字符列转换为行名称并将其从数据框中删除。

As an intermediate step I generate a data frame with one column as character strings and the rest are numbers. I'd like to convert it to a matrix, but first I have to convert that character column into row names and remove it from the data frame.

在 dplyr 中是否有一种简单的方法？与 add_rownames（）相反的 to_rownames（）的功能

Is there a simpe way to do this in dplyr? A function like to_rownames() that is opposite to add_rownames()?

我看到一个使用自定义函数的解决方案，但实际上并不适用于哲学。

I saw a solution using a custom function, but it's really out of dplyr philosophy.

推荐答案

这提供了NSE&标准eval函数：

This provides NSE & standard eval functions:

library(dplyr)

df <- data_frame(a=sample(letters, 4), b=c(1:4), c=c(5:8))

reset_rownames <- function(df, col="rowname") {
  stopifnot(is.data.frame(df))
  col <- as.character(substitute(col))
  reset_rownames_(df, col)
}

reset_rownames_ <- function(df, col="rowname") {
  stopifnot(is.data.frame(df))
  nm <- data.frame(df)[, col]
  df <- df[, !(colnames(df) %in% col)]
  rownames(df) <- nm
  df
}

m <- "rowname"

head(as.matrix(reset_rownames(add_rownames(mtcars), "rowname")))
##                    mpg cyl disp  hp drat    wt  qsec vs am gear carb
## Mazda RX4         21.0   6  160 110 3.90 2.620 16.46  0  1    4    4
## Mazda RX4 Wag     21.0   6  160 110 3.90 2.875 17.02  0  1    4    4
## Datsun 710        22.8   4  108  93 3.85 2.320 18.61  1  1    4    1
## Hornet 4 Drive    21.4   6  258 110 3.08 3.215 19.44  1  0    3    1
## Hornet Sportabout 18.7   8  360 175 3.15 3.440 17.02  0  0    3    2
## Valiant           18.1   6  225 105 2.76 3.460 20.22  1  0    3    1

head(as.matrix(reset_rownames_(add_rownames(mtcars), m)))
##                    mpg cyl disp  hp drat    wt  qsec vs am gear carb
## Mazda RX4         21.0   6  160 110 3.90 2.620 16.46  0  1    4    4
## Mazda RX4 Wag     21.0   6  160 110 3.90 2.875 17.02  0  1    4    4
## Datsun 710        22.8   4  108  93 3.85 2.320 18.61  1  1    4    1
## Hornet 4 Drive    21.4   6  258 110 3.08 3.215 19.44  1  0    3    1
## Hornet Sportabout 18.7   8  360 175 3.15 3.440 17.02  0  0    3    2
## Valiant           18.1   6  225 105 2.76 3.460 20.22  1  0    3    1

也许 to_rownames（）或 set_rownames（）更有意义。 ¯\_（ツ）_ /¯ YMMV。

Perhaps to_rownames() or set_rownames() makes more sense. ¯\_(ツ)_/¯ YMMV.

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