Not working if one constrast is NA

[xmarti6]

Hi Dr Keon, awesome package! , I just found a bug when one of the contrasts is all set to NA,
see these two examples:

> my.df <- data.frame(a=as.integer(1:9), 
 group=factor(c(rep("A",2),rep("B",7))),
 b=c(runif(2),rep(NA,7)));my.df
  a group         b
1 1     A 0.9005048
2 2     A 0.4966779
3 3     B        NA
4 4     B        NA
5 5     B        NA
6 6     B        NA
7 7     B        NA
8 8     B        NA
9 9     B        NA
> mytable(group~.,data=my.df)
Error in lm.wfit(x, y, w, offset = offset, singular.ok = singular.ok,  : 
  NA/NaN/Inf in 'x'
> 
> 
>   
>   
> my.df <- data.frame(a=as.integer(1:9), 
 group=factor(c(rep("A",2),rep("B",7))),
 b=c(rep(NA,2),runif(7)));my.df
  a group          b
1 1     A         NA
2 2     A         NA
3 3     B 0.94365337
4 4     B 0.33983796
5 5     B 0.09819898
6 6     B 0.76511246
7 7     B 0.34347543
8 8     B 0.44897411
9 9     B 0.36672965
> mytable(group~.,data=my.df)
Error in `contrasts<-`(`*tmp*`, value = contr.funs[1 + isOF[nn]]) : 
  contrasts can be applied only to factors with 2 or more levels

Many thanks