分配给R中的可变数据帧(Assign to a variable data frame in R)

 我正在尝试将一列数据分配给现有数据框中的新列。 数据框在循环中改变，从scores.d到score.e。 我希望的输出是用scores.X $ new.col填充vals，其中X用当前dfname替换。 
 
dfnames <- c("d","e")
scores.d <- data.frame(x = 1, y = 1:10)
scores.e <- data.frame(x = 2, y = 10:20)
vals <- 60:70

for (i in seq_along(dfnames)){
   assign(get(paste0("scores.",dfnames[i]))$new.col,vals)
}

Error in assign(get(paste0("scores.", dfnames[i]))$new.col, vals) : 
  invalid first argument
 
 这给了我一个错误，因为assign当我需要包含列名时，正在寻找一个字符串作为第一个参数。 只需将$ new.col添加到paste命令即可（假定$不会从字符串转换）。 
 
 我是R新手，不知道分配事情的注意事项。 我想制作一个数据框架列表，然后用vals填充每个数据框，但是它没有工作，因为我指定了特定的列，在我的真实数据中，数据框架无论如何都是预先存在的，我只是试图添加它们这里。 思考？ 
 
 编辑* @贾森提供了一个答案，通过分配值给一个临时变量，然后分配回来。 为我的目的工作正常，但我曾尝试用字符串列表代替通过paste0()创建名称，它仍然给我错误。 首先，贾森的工作答案是： 
 
dfnames <- c("d","e")
scores.d <- data.frame(x = 1, y = 1:10)
scores.e <- data.frame(x = 2, y = 11:20)
vals <- 61:70

for (i in dfnames){ #don't need seq_along

    dat<-get(paste0("scores.",i)) #pull up the data 
    dat$new.col<-vals
    assign(paste0('scores.',i),dat) #replace old data frame with new
}
 
 现在有一个名称列表替换粘贴过程（请注意对seq_along的更改）： 
 
dfnames <- c("d","e")
scores.d <- data.frame(x = 1, y = 1:10)
scores.e <- data.frame(x = 2, y = 11:20)
vals <- 61:70

# for demonstrative purposes only, these were created in a loop in my code
full.dfnames[1] <- "Scores.d"
full.dfnames[2] <- "Scores.e"

for (i in seq_along(dfnames)){ #added seq_along back for the name index

    dat<-get(full.dfnames[i]) #pull up the data 
    dat$new.col<-vals
    assign(full.dfnames[i],dat) #replace old data frame with new
}

>Error in assign(get(paste0("scores.", dfnames[i]))$new.col, vals) : 
      invalid first argument

I am trying to assign a column of data to a new column in an existing data frame. The data frame changes in a loop, from scores.d, to scores.e. My desired output is to have scores.X$new.col populated with the vals, where X is replaced with the current dfname. 
 
dfnames <- c("d","e")
scores.d <- data.frame(x = 1, y = 1:10)
scores.e <- data.frame(x = 2, y = 10:20)
vals <- 60:70

for (i in seq_along(dfnames)){
   assign(get(paste0("scores.",dfnames[i]))$new.col,vals)
}

Error in assign(get(paste0("scores.", dfnames[i]))$new.col, vals) : 
  invalid first argument
 
This gives me an error, because assign is looking for a character string as the first argument, when I need it to include the column name. Simply adding $new.col to the paste command doesn't work (assume $ doesn't translate from string).
 
I am new to R and don't know the dos and don'ts of assigning things. I thought to make a list of data frames, then populate each with vals, but it didnt work as I am specifying particular columns, in my real data, the data frames are pre-existing anyway, I'm just trying to add to them here. Thoughts? 
 
EDIT* @Jason has provided an answer, by allocating the values to a temporary variable, then assigning it back. Works fine for my purposes, however I had tried it with a list of strings in place of creating the names via paste0(), and it still gave me the error. First, Jason's working answer: 
 
dfnames <- c("d","e")
scores.d <- data.frame(x = 1, y = 1:10)
scores.e <- data.frame(x = 2, y = 11:20)
vals <- 61:70

for (i in dfnames){ #don't need seq_along

    dat<-get(paste0("scores.",i)) #pull up the data 
    dat$new.col<-vals
    assign(paste0('scores.',i),dat) #replace old data frame with new
}
 
Now with a list of names replacing the paste procedure (note the change to seq_along):
 
dfnames <- c("d","e")
scores.d <- data.frame(x = 1, y = 1:10)
scores.e <- data.frame(x = 2, y = 11:20)
vals <- 61:70

# for demonstrative purposes only, these were created in a loop in my code
full.dfnames[1] <- "Scores.d"
full.dfnames[2] <- "Scores.e"

for (i in seq_along(dfnames)){ #added seq_along back for the name index

    dat<-get(full.dfnames[i]) #pull up the data 
    dat$new.col<-vals
    assign(full.dfnames[i],dat) #replace old data frame with new
}

>Error in assign(get(paste0("scores.", dfnames[i]))$new.col, vals) : 
      invalid first argument

原文：https://stackoverflow.com/questions/28891156