如何在 R 中索引预测 plm 对象

Question

在 plm 对象上使用 predict() 函数给出固定效应模型中每个实体的样本预测值。

如何索引生成的双对象以获得仅一个实体的预测值？

给出的例子：

library(plm)

data("Produc", package = "plm")
zz <- plm(log(gsp) ~ log(pcap) + log(pc) + log(emp) + unemp,
          data = Produc, index = c("state","year"))

yy=predict(zz)

# this returns only the first element of the ARIZONA entity prediction. 
yy['ARIZONA']

#Output from above code
> yy['ARIZONA']
   ARIZONA 
-0.4264009 

#Expected output:

> yy
       ALABAMA        ALABAMA        ALABAMA        ALABAMA        ALABAMA 
 -0.2361898231  -0.2189895892  -0.1696057318  -0.1115933089  -0.0837388837 
       ALABAMA        ALABAMA        ALABAMA        ALABAMA        ALABAMA 
 -0.0927599459  -0.0162445537   0.0236004000   0.0771475623   0.0973429273 
       ALABAMA        ALABAMA        ALABAMA        ALABAMA        ALABAMA 
  0.0956672093   0.0784827429   0.0501708544   0.0640040527   0.1157573807 
       ALABAMA        ALABAMA        ARIZONA        ARIZONA        ARIZONA 
  0.1541848055   0.1727639012  -0.4264009370  -0.3666204604  -0.2707038121 
       ARIZONA        ARIZONA        ARIZONA        ARIZONA        ARIZONA 
 -0.1809125087  -0.1410211123  -0.1802185768  -0.1477399971  -0.0839823046 
       ARIZONA        ARIZONA        ARIZONA        ARIZONA        ARIZONA 
  0.0138358070   0.0985224005   0.1273115184   0.1711627777   0.1495094189 
       ARIZONA        ARIZONA        ARIZONA        ARIZONA     
  0.1919410264   0.2873534379   0.3458664549   0.4120968673

我的问题是，如何操作 predict() 对象来获取我的一个实体的完整预测值集？

Answer 1

您的代码不明确，因此请检查 names，它在括号内给出了一个布尔值。

yy[names(yy) %in% "ARIZONA"]
#     ARIZONA     ARIZONA     ARIZONA     ARIZONA     ARIZONA     ARIZONA 
# -0.42640094 -0.36662046 -0.27070381 -0.18091251 -0.14102111 -0.18021858 
#     ARIZONA     ARIZONA     ARIZONA     ARIZONA     ARIZONA     ARIZONA 
# -0.14774000 -0.08398230  0.01383581  0.09852240  0.12731152  0.17116278 
#    ARIZONA     ARIZONA     ARIZONA     ARIZONA     ARIZONA 
# 0.14950942  0.19194103  0.28735344  0.34586645  0.41209687

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