我有一个看起来像这样的data.table:
require("data.table")
dt1 <- data.table(VAR1 = c("Brick","Sand","Concrete","Stone"), VAR2 = c(100,23,76,43), VAR3 = c("Place","Location","Place","Vista"), VAR4 = c("Place","Tree","Wood","Vista"), VAR5 = c("Place","Tree","Wood","Forest"))
我想按以下顺序将命名列(我的真实数据还有其他列)粘贴在一起:VAR2,VAR1,VAR3,VAR4和VAR5。但是,我有两个条件:
我的预期输出将如下所示:
dt2 <- data.table(VAR6 = c("100 Brick, Place","23 Sand, Location, Tree","76 Concrete, Place, Wood","43 Stone, Vista, Forest"))
我们可以按do.call(paste
的顺序选择列,然后使用正则表达式删除重复的单词,然后使用.SDcols
dt1[, .(VAR6 = sub(",", " ", gsub("\\b(\\w+)\\b\\s*,\\s*(?=.*\\1)", "",
do.call(paste, c(.SD, sep=",")), perl = TRUE))),
.SDcols = names(dt1)[c(2:1, 3:5)]]
# VAR6
#1: 100 Brick,Place
#2: 23 Sand,Location,Tree
#3: 76 Concrete,Place,Wood
#4: 43 Stone,Vista,Forest
或按行顺序分组并执行paste
V6 <- dt1[, sprintf("%s %s, %s", VAR2, VAR1,
toString(unique(unlist(.SD)))), 1:nrow(dt1), .SDcols = VAR3:VAR5]$V1
data.table(V6)
# V6
#1: 100 Brick, Place
#2: 23 Sand, Location, Tree
#3: 76 Concrete, Place, Wood
#4: 43 Stone, Vista, Forest