> for (i in 3:7) {+   fit <- lrm(depress2~rcs(SD,3)+Household+Gender+Mar+age1+HC+TWI+Chronic+exercise+Smoking+Driking+LB1+Bedtime1,data=figure3)+   tmp <- extractAIC(fit)+   if(i == 3) {AIC = tmp[2]; nk = 3}+   if( tmp[2] < AIC) {AIC = tmp[2]; nk = i} + }Error in if (tmp[2] < AIC) { : missing value where TRUE/FALSE needed