如何在RStudio上进行PartitionBy (SQL)排序

Question

所以我有这样的东西:

data.frame(content = c("a","a","b","b","c","c"),
eje = c("politics","sports","education","sports","health","politics"),
value = c(3,2,1,2,1,1))

我想按content分组，并保留eje中value值最高的值，并在两者相等时保留这两个值。

在这个示例中，我将保留:

data.frame(content = c("a","b","c","c"),
eje = c("politics","sports","health","politics"),
value = c(3,2,1,1))`

在SQL上，我会做一些像RANK OVER PARTITION BY(内容，DESC值)，然后过滤值为"1">

Answer 1

d = data.frame(content = c("a","a","b","b","c","c"),
eje = c("politics","sports","education","sports","health","politics"),
value = c(3,2,1,2,1,1))
library(dplyr)
d %>%
group_by(content) %>%
slice_max(value)
# # A tibble: 4 × 3
# # Groups:   content [3]
#   content eje      value
#   <chr>   <chr>    <dbl>
# 1 a       politics     3
# 2 b       sports       2
# 3 c       health       1
# 4 c       politics     1

Answer 2

data.tableoption:

library(data.table)
dt <- data.table(df)
dt[dt[, .I[value == max(value)], by=content]$V1]

输出:

content      eje value
1:       a politics     3
2:       b   sports     2
3:       c   health     1
4:       c politics     1