在约束下生成随机虚拟

Question

在某些条件下，我无法在R中生成以下虚拟变量。

var1<-c("a","b","c","a","a","a","b","c","b","a")
var2<-c("val1","val1","val1","val1","val2","val1","val3","val3","val2","val1")
db<-data.frame(cbind(var1,var2))

我想根据以下规则生成列var3：

• 如果var2 =＆＃34; val2＆＃34; OR var2 =＆＃34; val3＆＃34;然后var3 = 1
• 如果var2 =＆＃34; val1＆＃34; AND var1 =＆＃34; a＆＃34;然后必须随机分配n次（让＃3说3）值1，否则为0。
• 如果var2 =＆＃34; val1＆＃34; AND var1！=＆＃34; a＆＃34;然后var3 = 1

我尝试做的是在规定的条件下随机排除一些行（标记为0）。

有人可以帮帮我吗？

Answer 1

似乎你可以从制作所有var3 1开始，然后只制作符合第二个条件零的那个

db$var3 = 1
x = which(db$var2 == "val1" & db$var1 == "a") #Get indices where 2nd condition is met
db$var3[sample(x, length(x) - 3)] = 0 #Assign 0 all indices in x except 3