替换 R 中 2 个数据帧之间的行

Question

I have 2 data frames, and I want to write a code that will allow me to check if a row from data frame1 exist in data frame2, and if so then I want to replace the row(s) from data frame1 with the row(s) from data frame2. Here is an example:

dataframe1:

name	A	B
AA	1	1
BB	1	0
CC	0	1

dataframe2:

name	A	B
AA	1	2
DD	1	3
EE	4	1

I want to switch rows between both dataframes, and the outcome will be:

dataframe1:

name	A	B
AA	1	2
BB	1	0
CC	0	1

To clarify, I want to row AA from dataframe1 to be switched by the row AA dataframe2.

This is what I tried to do:

df1[which(df1$name %in% df2$name)[1:nrow(df2)],] <- df2

And:

df1$name[match(df2$name,df1$name)] <- df2$name

Both didn't work unfortunately.

Thanks for helping!

Answer 1

Does this work:

df1
  name A B
1   AA 1 1
2   BB 1 0
3   CC 0 1
df2
  name A B
1   AA 1 2
2   DD 1 3
3   EE 4 1
df2$name %in% df1$name
[1]  TRUE FALSE FALSE
df1[df1$name %in% df2$name, ] = df2[df2$name %in% df1$name, ]
df1
  name A B
1   AA 1 2
2   BB 1 0
3   CC 0 1

Answer 2

The natural_join is the function you are looking for

library(rqdatatable)

dataframe1 <- data.frame(
        name = c('AA', 'BB', 'CC'),
        A = c(1,1,0),
        B = c(1,0,1)
    )

dataframe2 <- data.frame(
    name = c('AA', 'DD', 'EE'),
    A = c(1,1,4),
    B = c(2,3,1)
)

natural_join(dataframe2, dataframe1, by = "name",
             jointype = 'RIGHT')

Answer 3

You can make an update join :

i <- match(df1$name, df2$name)
j <- which(!is.na(i))
df1[j,] <- df2[i[j],]

df1
#  name A B
#1   AA 1 2
#2   BB 1 0
#3   CC 0 1

Data:

df1 <- data.frame(name = c("AA","BB","CC"), A = c(1,1,0), B = c(1,0,1))
df2 <- data.frame(name = c("AA","DD","EE"), A = c(1,1,4), B = c(2,3,1))

Answer 4

A dplyr way using across , left_join and coalesce

library(dplyr, warn.conflicts = F)

df1 <- data.frame(name = c("AA","BB","CC"), A = c(1,1,0), B = c(1,0,1))
df2 <- data.frame(name = c("AA","DD","EE"), A = c(1,1,4), B = c(2,3,1))

df1 %>% left_join(df2, by = 'name') %>%
  mutate(across(ends_with('.y'), ~coalesce(., get(gsub('\\.y', '\\.x', cur_column()))),
                .names = "{gsub('.y', '', .col)}"), .keep = 'unused')

#>   name A B
#> 1   AA 1 2
#> 2   BB 1 0
#> 3   CC 0 1

^{Created on 2021-07-06 by the reprex package (v2.0.0)}