[R] apply fn to many dataframes

Hi, Say I have dataframes d1, d2, ... , dn, and I want to apply a function to all of them. For example, say I want to change the name of the second variable in each dataframe to "x2". The following doesn't work: a = list(d1,d2,d3,d4) lapply(a,function(x) names(x)[2] = "x2") What would work

[R] lrm in Design package, missing value problem

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[R] lrm in Design package, missing value problem

Hi, This concerns lrm in the Design package, which I need for the clustered errors option with panel data. I have created a variable (using sign()) that has values -1, 0, and 1 (and some NAs). call this variable x3. lrm does not like t = lrm(y ~ x1 + x2 + I(x3==-1) + I(x3==1), data=data,x