我需要提取匹配的字符串部分和两列之间不匹配的字符串:
x <- c("apple, banana, pine nuts, almond")
y <- c("orange, apple, almond, grapes, carrots")
j <- data.frame(x,y)
获得:
yonly <- c("orange, grapes, carrots")
xonly <- c("banana, pine nuts")
both <- c("apple, almond")
k <- data.frame(cbind(x,y,both,yonly,xonly))
我研究了str_detect,交叉等等,但这些似乎需要对现有细胞进行大手术以将它们分成不同的细胞。这是一个与其他列相关的大型数据集,因此我宁愿不要过多地操纵它。你能帮我提出一个更简单的解决方案吗?
谢谢!
答案 0 :(得分:4)
您可以使用setdiff
和intersect
> j <- data.frame(x,y, stringsAsFactors = FALSE)
> X <- strsplit(j$x, ",\\s*")[[1]]
> Y <- strsplit(j$y, ",\\s*")[[1]]
>
> #Yonly
> setdiff(Y, X)
[1] "orange" "grapes" "carrots"
>
> #Xonly
> setdiff(X, Y)
[1] "banana" "pine nuts"
>
> #Both
> intersect(X, Y)
[1] "apple" "almond"
答案 1 :(得分:1)
如您所述,要创建较长数据框j
的额外列,您可以将mapply
与Jilber Urbina的答案中使用的方法一起使用...
#set up data
x <- c("apple, banana, pine nuts, almond")
y <- c("orange, apple, almond, grapes, carrots")
j <- data.frame(x,y,stringsAsFactors = FALSE)
j[,c("yonly","xonly","both")] <- mapply(function(x,y) {
x2 <- unlist(strsplit(x, ",\\s*"))
y2 <- unlist(strsplit(y, ",\\s*"))
yonly <- paste(setdiff(y2, x2), collapse=", ")
xonly <- paste(setdiff(x2, y2), collapse=", ")
both <- paste(intersect(x2, y2), collapse=", ")
return(c(yonly, xonly, both)) },
j$x,j$y)
j
x y yonly xonly both
1 apple, banana, pine nuts, almond orange, apple, almond, grapes, carrots orange, grapes, carrots banana, pine nuts apple, almond