[R] howto calculate column means in data frame

Maas James Dr (MED) J.Maas at uea.ac.uk
Sun Apr 10 17:27:33 CEST 2011


Long story short, I have a big iterative procedure that produces a long list of data.frames such as the one called
"results" here.  Is there an easy way to produce a similar list of data.frames comprised of the mean of each of the
columns in results, such that it ends up like the one I've shown in "resultsmean" below?

I've tried apply and lapply, still not got the correct arguments.  As usual, TIA.

Jim

> results
[[1]]
       name    LOR23       BIA23       MSE23          H0R23
1 0.2111122   -1.012228   -0.095937    0.035650        1.00
2 0.2111122   -0.836300    0.079991    0.042322        0.75
3 0.2111122   -0.518631    0.397659    0.214593        0.50


[[2]]
       name    LOR23       BIA23       MSE23          H0R23
1 0.2211122   -0.724630    0.191660    0.051308           1
2 0.2211122   -0.781812    0.134478    0.033872           1
3 0.2211122   -0.522109    0.394181    0.164628        0.75


would like

> resultsmean
[[1]]
       name    LOR23       BIA23       MSE23          H0R23
1 0.2111122   -0.78333    0.12734     0.097160        0.75

[[2]]
       name    LOR23       BIA23       MSE23          H0R23
1 0.2211122   -0.67566    0.2400      0.08266         0.916

===============================
Dr. Jim Maas
University of East Anglia



More information about the R-help mailing list