r - 如何通过R中的名称将向量转换为矩阵？

Question

我有这个向量

   ID   var2     ID   var2   var1     ID   var2     ID   var3 
"1000"    "1" "1001"    "1"    "1" "1002"    "7" "1003"    "3" 

可以从

x=c("1000","1","1001","1","1","1002","7","1003","3")
names(x)=c("ID","var2","ID","var2","var1","ID","var2","ID","var3")

我会把它转换成这个尺寸为 4x4 的矩阵:

ID        var1     var2    var3
"1000"     NA       "1"     NA
"1001"     "1"      "1"     NA
"1002"     NA       "7"     NA
"1003"     NA       NA     "3"  

请问你能帮帮我吗？

Answer 1

我们可以 split向量 'x' 通过基于 'ID' 出现的分组向量，match具有列表元素名称的唯一名称 ('nm1') order然后 rbind得到预期的输出

 nm1 <- sort(unique(names(x)))
 do.call(rbind,lapply(split(x, cumsum(grepl('ID', names(x)))), function(y)
        setNames(y[match(nm1, names(y))], nm1)
        ))
 # ID     var1 var2 var3
 #1 "1000" NA   "1"  NA  
 #2 "1001" "1"  "1"  NA  
 #3 "1002" NA   "7"  NA  
 #4 "1003" NA   NA   "3" 

或使用 row/col创建空矩阵后的索引。

indx <- match(names(x), nm1)
m1 <- matrix(, nrow= max(tabulate(indx)), ncol=length(nm1), 
             dimnames=list(NULL, nm1))
m1[cbind(cumsum(indx==1), indx)] <- x