Re: [R] Grouping of data frames to calculate means

2009-04-06 Thread Thomas Lumley
On Mon, 6 Apr 2009, Steve Murray wrote: Dear R Users, I have 120 data frames of the format table_198601, table_198602... table_198612, table_198701, table_198702... table_198712 through to table_199512 (ie. the first 4 digits are years which vary from 1986 to 1995, and the final two digits

[R] Grouping of data frames to calculate means

2009-04-06 Thread Steve Murray
Dear R Users, I have 120 data frames of the format table_198601, table_198602... table_198612, table_198701, table_198702... table_198712 through to table_199512 (ie. the first 4 digits are years which vary from 1986 to 1995, and the final two digits are months which vary from 01 to 12 for eac