R 如何读取CSV的特定列时，给定标题作为向量

我有一个没有标题行的大型CSV文件，标题对我来说是一个向量.我希望在不加载整个文件的情况下使用文件列的子集.所需列的子集以单独列表的形式提供.

Edit: in this case, the column names provided in the header list are important. This MRE only has 4 column names, but the solution should work for a large dataset with pre-specified column names. The catch is that the column names are only provided externally, not as a header in the CSV file.

1,2,3,4
5,6,7,8
9,10,11,12

header <- c("A", "B", "C", "D")
subset <- c("D", "B")

到目前为止，我一直在以以下方式读取数据，这将获得我想要的结果，但首先加载整个文件.

# Setup

library(readr)

write.table(
  structure(list(V1 = c(1L, 5L, 9L), V2 = c(2L, 6L, 10L), V3 = c(3L, 7L, 11L), V4 = c(4L, 8L, 12L)), class = "data.frame", row.names = c(NA, -3L)),
  file="sample-data.csv",
  row.names=FALSE,
  col.names=FALSE,
  sep=","
)

header <- c("A", "B", "C", "D")
subset <- c("D", "B")

# Current approach

df1 <- read_csv(
  "sample-data.csv",
  col_names = header
)[subset]

df1

# A tibble: 3 × 2
      D     B
  <dbl> <dbl>
1     4     2
2     8     6
3    12    10

如何才能在不先加载整个文件的情况下获得相同的结果？

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