想对数据库中两个体重数值的比较，重新定义为新变量，就编写了如下的for循环代码，
newdt2000$weight_1<-newdt2000$g10*0.05*2
newdt2000$weight_2<-newdt2000$g101_2-newdt2000$g10
newdt2000$WL<-NA
for (i in 1:nrow(newdt2000)) {
  if (newdt2000$weight_1[i]>=newdt2000$weight_2[i]) {newdt2000$WL[i,]<-0
  }else {newdt2000$WL[i,]<-1
  }
}

但结果显示
“Error in if (newdt2000$weight_1[i] >= newdt2000$weight_2[i]) { :
  missing value where TRUE/FALSE needed”
不知道该如何修改，求大神指教！感谢！