我有以下两个数据表:
dt1 <- data.table(range_col = c(1, 7, 10, 15, 20), new_col = NA)
dt2 <- data.table(min_val = c(0, 6, 11, 16), max_val = c(5, 10, 15, 20), value_col = c(100, 200, 300, 400))
现在，基于数据表‘DT2’中‘min_val’和amp；‘max_val’字段中列‘range_ol’的值和值之间的范围，必须将‘dt2’的‘value_ol’中的相应值分配给‘dt1’的‘new_ol’.
您可以使用findInterval:
dt1[, new_col := dt2$value_col[findInterval(range_col, dt2$min_val)]]
# range_col value_col
# 1: 1 100
# 2: 7 200
# 3: 10 200
# 4: 15 300
# 5: 20 400
另一个(更安全的)data.table选项是foverlaps:
setkey(dt2, min_val, max_val)
dt1[, range_col2 := range_col]
foverlaps(dt1, dt2, by.x = c("range_col", "range_col2"))[, c("range_col", "value_col")]
而在dplyr年:
library(dplyr)
inner_join(dt1, dt2, by = join_by(between(range_col, min_val, max_val))) %>%
select(range_col, value_col)