将合并后缀扩展到所有非按列 [英] Extending Suffixes in Merge to All Non-by Columns

问题描述

suffixes仅适用于通用列名.无论如何，是否可以将其扩展到其余的列，而无需在合并之前手动更新列?

suffixes in merge works only on common column names. Is there anyway to extend this to the rest of the columns as well without manually updating columns before the merge?

就是-

df1 <- data.table(
a = c(1,2,3,4,5,6),
b = c('a','b','f','e','r','h'),
d = c('q','l','o','n','q','z')
)

df2 <- data.table(
a = c(1,2,3,4,5,6),
d = c('q','l','o','n','q','z')
)

colnames(merge(df1,df2, by = 'a', suffixes = c("1","2")))
#[1] "a"  "b"  "d1" "d2" what it does
#[1] "a"  "b1" "d1" "d2" what I'd like it to do

我当前处理此问题的方式类似于@mrip的答案.

The current way I'm handling this resembles @mrip's answer.

df1 <- data.table(
a = c(1,2,3,4,5,6),
b = c('a','b','f','e','r','h'),
r = c('a','b','f','e','r','h'),
d = c('q','l','o','n','q','z')
)

df2 <- data.table(
a = c(1,2,3,4,5,6),
c = c('a','b','f','e','r','h'),
q = c('a','b','f','e','r','h'),
d = c('q','l','o','n','q','z')
)

dfmerge <- (merge(df1,df2, by = c("a"), suffixes = c("1","2")))

setnames(
dfmerge,
setdiff(names(df1),names(df2)),
paste0(setdiff(names(df1),names(df2)),"1")
)

setnames(
dfmerge,
setdiff(names(df2),names(df1)),
paste0(setdiff(names(df2),names(df1)),"2")
)

colnames(dfmerge)
#[1] "a"  "b1" "r1" "d1" "c2" "q2" "d2"

推荐答案

一个简单的解决方案:

mrg<-(merge(df1,df2, by = 'a', suffixes = c("1","2")))
setnames(mrg,paste0(names(mrg),ifelse(names(mrg) %in% setdiff(names(df1),names(df2)),"1","")))
setnames(mrg,paste0(names(mrg),ifelse(names(mrg) %in% setdiff(names(df2),names(df1)),"2","")))

> names(mrg)
[1] "a"  "b1" "d1" "d2"

感谢里卡多·萨波特塔(Ricardo Saporta)的评论，此注释大为清除了该错误并教给我一些新的提示！

thanks to comments by Ricardo Saporta for cleaning this up considerably and teaching me a few new tips!

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