R- 列匹配，用对应值的另一列创建新列

Question

我有两个数据框：

df1<- data.frame(place=c("KARACA ADANA","ASIL BOLU","GAZIANTEP","YUKARI/MERSIN"))

df2<- data.frame(city=c("ADANA","BOLU","ANTEP","MERSIN"), neighbor=c("KARACA","ASIL","GAZI","YUKARI"))

我需要匹配列 df1$place 和 df2$neighbor。如果 df1$place 包含 df2$neighbor 中的单词，它应该通过复制 df2$city of matches 的相应值来为 df1$newcol 创建一个新列。

df1$newcol <- data.frame(place=c("KARACA ADANA","ASIL BOLU","GAZIANTEP","YUKARI/MERSIN") ,city=c("ADANA","BOLU","ANTEP","MERSIN"))

Answer 1

这是一种方法 sapply 来自 base R:

如果您只想匹配整个单词，可以使用正则表达式。 \b 查找单词边界。

ind <- unlist(sapply(df2$neighbor, function(x) grep(paste0("\b",x,"\b"),df1$place)))
ind2 <- rep(1:length(df2$neighbor),
            times = sapply(df2$neighbor, function(x) length(grep(paste0("\b",x,"\b"),df1$place))))
df1$newcol <- NA
df1$newcol[ind] <- as.character(df2$city[ind2])
df1
#          place newcol
#1  KARACA ADANA  ADANA
#2     ASIL BOLU   BOLU
#3     GAZIANTEP   <NA>
#4 YUKARI/MERSIN MERSIN
#5 YUKARI/MERSIN MERSIN
#6     GAZIANTEP   <NA>
#7     ASIL BOLU   BOLU
#8  KARACA ADANA  ADANA

示例数据

df1<- data.frame(place=c(c("KARACA ADANA","ASIL BOLU","GAZIANTEP","YUKARI/MERSIN"),
                         rev(c("KARACA ADANA","ASIL BOLU","GAZIANTEP","YUKARI/MERSIN"))))

Answer 2

尝试这样做

library(tidyverse)
df1 %>% 
  rowwise() %>% 
  mutate(out = df2$city[str_which(place, df2$city)])

R- 列匹配，用对应值的另一列创建新列

R- Column match, create new column with another column of corresponding value

r

match

string-matching