使用存储在变量中的列名来连接数据表

I have 2 data.tables:

我有2个data.tables：

library(data.table)
dt1 <- data.table(id = 1:5, value1 = 11:15, value2 = 21:25, value3 = 36:40)
dt2 <- data.table(name = c("value1", "value1", "value1", "value1", 
                            "value2", "value2", "value2", "value3", "value3"), 
              valueMin = c(10, 13, 14, 18, 21, 24, 25, 36, 38), 
              valueMax = c(13, 14, 18, 20, 24, 25, 27, 38, 42), 
              label = c(101:104, 201:203, 301:302))
> dt1
   id value1 value2 value3
1:  1     11     21     36
2:  2     12     22     37
3:  3     13     23     38
4:  4     14     24     39
5:  5     15     25     40
> dt2
     name valueMin valueMax label
1: value1       10       13   101
2: value1       13       14   102
3: value1       14       18   103
4: value1       18       20   104
5: value2       21       24   201
6: value2       24       25   202
7: value2       25       27   203
8: value3       36       38   301
9: value3       38       42   302
libr