数据表R:合并多个data.table中的选定列

library(data.table)

# 创建示例 data.table
dt1 <- data.table(id = 1:3, name = c("Alice", "Bob", "Charlie"), age = c(25, 30, 35))
dt2 <- data.table(id = 1:3, city = c("New York", "Los Angeles", "Chicago"), salary = c(70000, 80000, 90000))

# 水平合并
merged_dt <- merge(dt1, dt2, by = "id")
print(merged_dt)

# 垂直合并
vertical_merged_dt <- rbindlist(list(dt1, dt2), use.names = TRUE)
print(vertical_merged_dt)

dt2 <- data.table(id = 1:3, city = c("New York", "Los Angeles", "Chicago"), salary = c(70000, 80000, 90000))
setnames(dt2, "id", "id_dt2")  # 重命名重复的列
merged_dt <- merge(dt1, dt2, by.x = "id", by.y = "id_dt2")
print(merged_dt)

# 检查并处理不一致的数据
dt1 <- dt1[id %in% dt2$id]
merged_dt <- merge(dt1, dt2, by = "id")
print(merged_dt)