R中的循环：使用索引括号子集

Question

我正在尝试在 R 中编写一个 for 循环，使用索引值来对数据进行子集化，但我得到了我的括号意外的错误。当我从代码主体中删除它们时，我收到一个错误，即找不到我正在创建的对象（是的！不应该找到它......循环应该创建它）。我熟悉循环，但在 R 中编写循环的经验较少。要明确的是，我不明白何时使用单括号 [i] 或双括号 [[i]]。我只是希望我的循环成功运行并生成 24 次效果大小计算。

我尝试了许多 [i]、[[i]] 和 i 的组合。我也更改了指标上的变量类型，但无济于事。

感谢您的帮助！

我目前的代码如下：

数据集示例：

structure(list(Group = c(1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 
2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 3, 3), id = c("Person1", "Person1", 
"Person1", "Person1", "Person1", "Person1", "Person1", "Person1", 
"Person2", "Person2", "Person2", "Person2", "Person2", "Person2", 
"Person2", "Person2", "Person3", "Person3", "Person3", "Person3", 
"Person3", "Person3", "Person3", "Person3"), year = c(2, 2, 2, 
2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2
), indicator = c(1L, 2L, 3L, 4L, 5L, 6L, 7L, 8L, 1L, 2L, 3L, 
4L, 5L, 6L, 7L, 8L, 1L, 2L, 3L, 4L, 5L, 6L, 7L, 8L), score = c(3.5, 
3.5, 2, 3, 3.5, 4, 3, 4, 2.25, 2.5, 1.75, 1.5, 2, 2.75, 2, 2.75, 
1.75, 2, 1.75, 2, 2, 2.5, 2, 2.5)), class = c("tbl_df", "tbl", 
"data.frame"), row.names = c(NA, -24L))

当前形式的代码：

library(effsize)

for(i in 1:8){
a.1.1.[i]<-cohen.d((df[df$Group==1 & df$indicator==[i],]$score), (df[df$Group==2 & df$indicator==[i],]$score),pooled=T, hedges.correction = T, na.rm=T)

a.1.2.[i]<-cohen.d((df[df$Group==2 & df$indicator==[i],]$score), (df[df$Group==3 & df$indicator==[i],]$score),pooled=T, hedges.correction = T, na.rm=T)

a.1.3.[i]<-cohen.d((df[df$Group==1 & df$indicator==[i],]$score), (df[df$Group==3 & df$indicator==[i],]$score),pooled=T, hedges.correction = T, na.rm=T)
}

Answer 1

将数据存储在列表中：

a.1.1 <- vector('list', 8)
a.1.2 <- vector('list', 8)
a.1.3 <- vector('list', 8)

for(i in 1:8) {
  a.1.1[[i]] <- cohen.d((df$score[df$Group==1 & df$indicator==i]), 
                        (df$score[df$Group==2 & df$indicator==i]),
                         pooled=T, hedges.correction = T, na.rm=T)
  
  a.1.2[[i]]<-cohen.d((df$score[df$Group==2 & df$indicator==i]), 
                     (df$score[df$Group==3 & df$indicator==i]),
                      pooled=T, hedges.correction = T, na.rm=T)
  
  a.1.3[[i]] <- cohen.d((df$score[df$Group==1 & df$indicator==i]), 
                      (df$score[df$Group==3 & df$indicator==i]),
                       pooled=T, hedges.correction = T, na.rm=T)
}