R-列匹配，新建一列与另一列对应的值[重复]。

Question

这个问题在这里已经有了答案:

dplyr: inner_join with a partial string match. (4个答案)

封闭 20天前.

我有两个数据框架。

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df1$place和df2$neighbor两列。如果df1$place包含了df2$neighbor中的单词，它应该通过复制df2$city的对应值来创建一个新的列到df1$newcol中。

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

Answer 1

这里有一个方法，有 sapply 从基础R。

如果你只想匹配完整的单词，你可以使用一个正则表达式。\\b 寻找一个词的边界。

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

试着

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