我有一组数据:
| date | code | x | y | 
| 2006-11-2 | A | 2.6552 | 1.4464 | 
| 2006-11-2 | A | 0.5093 | 3.6459 | 
| 2006-11-2 | A | 0.9517 | 7.0083 | 
| 2006-11-2 | b | 0.4968 | 2.162 | 
| 2006-11-2 | c | 1.3579 | 3.7838 | 
| 2006-11-2 | c | 3.9797 | 4.3198 | 
| 2006-11-4 | A | 1.8694 | 7.9508 | 
| 2006-11-11 | A | 1.8193 | 6.4134 | 
| 2006-11-11 | A | 2.3747 | 6.4259 | 
| 2006-11-11 | A | 2.3317 | 2.1684 | 
| 2006-11-11 | b | 1.7482 | 5.9709 | 
| 2006-11-11 | b | 2.7563 | 0.8506 | 
| 2006-11-11 | c | 8.0825 | 4.9486 | 
| 2006-11-16 | A | 2.7621 | 5.1945 | 
| 2006-11-16 | A | 2.7888 | 3.4157 | 
| 2006-11-16 | b | 5.5096 | 4.6652 | 
| 2006-11-16 | b | 3.0412 | 4.2405 | 
| 2006-11-16 | c | 2.0787 | 0 | 
| 2006-11-16 | c | 1.6449 | 4.9045 | 
| 2006-11-16 | c | 3.5056 | 4.0942 | 
| 2006-11-16 | c | 2.9297 | 5.8854 | 
根据date 和code排序了,我想建立新的一列数据,在同一日期内,相同的code,取X和Y中的最大值。
希望高手指点,谢谢大家了