使用 tidyr unity 将列值与列名组合

Question

我有一个data.frame 有几列：

set.seed(1)
df <- data.frame(cluster=LETTERS[1:4],group=c(rep("m",2),rep("f",2)),point=rnorm(4),err=runif(4,0.1,0.3))

我会添加另一列 "\n" concatenates 其各自行的所有列，其中列名位于值之前。

我知道：

library(tidyr)
library(dplyr)
tidyr::unite(df,text,sep="\n")

给我这个tibble：

                                         text
1  A\nm\n0.487429052428485\n0.286941046221182
2  B\nm\n0.738324705129217\n0.142428504256532
3  C\nf\n0.575781351653492\n0.230334753217176
4 D\nf\n-0.305388387156356\n0.125111019192263

但我想要的是这个tibble:

                                         text
1  cluster: A\ngroup: m\npoint: 0.487429052428485\nerr: 0.286941046221182
2  cluster: B\ngroup: m\npoint: 0.738324705129217\nerr: 0.142428504256532
3  cluster: C\ngroup: f\npoint: 0.575781351653492\nerr: 0.230334753217176
4 cluster: D\ngroup: f\npoint: -0.305388387156356\nerr: 0.125111019192263

有什么想法吗？

Answer 1

我们可以使用Map 和do.call

data.frame(text = do.call(paste, c(Map(function(x, y) 
                 paste(x, y, sep=": "), names(df), df), sep="\n")))

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或使用tidyverse，映射列（imap - 提供.y 作为列名），然后执行unite

library(tidyverse)
imap(df, ~ paste(.y, .x, sep=": ")) %>%
              as_tibble %>%
              unite(text, sep="\n")
# A tibble: 4 x 1
#  text                                                                     
#  <chr>                                                                    
#1 "cluster: A\ngroup: m\npoint: -0.626453810742332\nerr: 0.225822808779776"
#2 "cluster: B\ngroup: m\npoint: 0.183643324222082\nerr: 0.112357254093513" 
#3 "cluster: C\ngroup: f\npoint: -0.835628612410047\nerr: 0.14119491497986" 
#4 "cluster: D\ngroup: f\npoint: 1.59528080213779\nerr: 0.135311350505799"  

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或者正如@DanChaltiel 提到的那样

imap_dfr(df, ~ paste(.y, .x, sep = "; ")) %>%
      unite(text, sep = "\n")