R语言环境，计算极端降水RClimDex，出现下标出界 [img=0,1]file:///C:\Users\105\AppData\Roaming\Tencent\Users\493237809\QQ\WinTemp\RichOle\Y}24)TW)@`4~KK0]`2[YU8L.png[/img][img=0,1]file:///C:\Users\105\AppData\Roaming\Tencent\Users\493237809\QQ\WinTemp\RichOle\Y}24)TW)@`4~KK0]`2[YU8L.png[/img]，怎么回事？该怎么处理？