R如何使用列表的位置确定两列中每个元素的位置答案

【问题标题】：R how to determinate the position of each element in two columns using the position of a listR如何使用列表的位置确定两列中每个元素的位置
【发布时间】：2021-04-19 18:27:27
【问题描述】：

我有一个包含 2 列的数据框

groups
                   g1                 g2
1                Soil              Feces
2                Soil               Skin
3                Soil             Tongue
4                Soil         Freshwater
6                Soil              Ocean
8                Soil               Mock
11              Feces         Freshwater
12              Feces Freshwater (creek)
14              Feces Sediment (estuary)
18               Skin Freshwater (creek)
23             Tongue Freshwater (creek)
27         Freshwater Freshwater (creek)
31 Freshwater (creek)              Ocean
33 Freshwater (creek)               Mock

所以我想根据 g1 和 g2 列的所有元素的位置添加 2 个额外的列，如果我们根据 g1 和 g2 列提取单个元素

l <- union(unique(g$g1), unique(g$g2))

[1] "Soil"  "Feces" "Skin" "Tongue" "Freshwater" "Freshwater (creek)" "Ocean" "Mock" "Sediment (estuary)"

所以l中Soil的位置对应1，Faces对应2，以此类推：

Soil               : 1
Feces              : 2
Skin               : 3
Tongue             : 4
Freshwater         : 5
Freshwater (creek) : 6
Ocean              : 7
Mock               : 8
Sediment (estuary) : 9

所以我想在 2 个额外的列中添加 g1 和 g2 中的位置基数，如果土壤对应于 1，粪便对应于 2，那么 xg1 和 xg2 将对应于 1 和 2，类似于：

   groups
                       g1                 g2       xg1         xg2
    1                Soil              Feces        1          2
    2                Soil               Skin        1          3
    3                Soil             Tongue        1          4
    4                Soil         Freshwater        1          5
    6                Soil              Ocean        1          7         
    8                Soil               Mock        1          8
    11              Feces         Freshwater        2          5
    12              Feces Freshwater (creek)        2          6
    14              Feces Sediment (estuary)        2          9
    18               Skin Freshwater (creek)        3          6
    23             Tongue Freshwater (creek)        4          6
    27         Freshwater Freshwater (creek)        5          6
    31 Freshwater (creek)              Ocean        6          7
    33 Freshwater (creek)               Mock        6          8

我已经尝试使用列表 (l) 和命令进行循环，但我无法做到

非常感谢

【问题讨论】：

标签： r list dataframe

【解决方案1】：

解决方案

library(tidyverse)

# creating a key
key <- structure(list(V1 = c("Soil", "Feces", "Skin", "Tongue", "Freshwater", 
"Freshwater (creek)", "Ocean", "Mock", "Sediment (estuary)"), 
    V2 = c("1", "2", "3", "4", "5", "6", "7", "8", "9")), row.names = c(NA, 
-9L), class = "data.frame")

df %>%
  mutate(
    xg1 = key$V2[match(df$g1, key$V1)],
    xg2 = key$V2[match(df$g2, key$V1)]
    )

数据

df <- structure(list(g1 = c("Soil", "Soil", "Soil", "Soil", "Soil", 
"Soil", "Feces", "Feces", "Feces", "Skin", "Tongue", "Freshwater", 
"Freshwater (creek)", "Freshwater (creek)"), g2 = c("Feces", 
"Skin", "Tongue", "Freshwater", "Ocean", "Mock", "Freshwater", 
"Freshwater (creek)", "Sediment (estuary)", "Freshwater (creek)", 
"Freshwater (creek)", "Freshwater (creek)", "Ocean", "Mock")), class = "data.frame", row.names = c(NA, 
-14L))

【讨论】：