读取R中的CSV并按名称过滤列 [英] Read CSV in R and filter columns by name

问题描述

比方说，我有一个包含数十或数百列的CSV，而我想仅提取2或3列.我了解中所述的colClasses解决方案，这里，但是代码变得非常不可读.

Let's say I have a CSV with dozens or hundreds of columns and I want to pull in just about 2 or 3 columns. I know about the colClasses solution as described here but the code gets very unreadable.

我想要来自 pandas的usecols之类的东西'read_csv .

I want something like usecols from pandas' read_csv.

加载所有内容并仅在事后选择不是解决方案(文件太大，无法容纳在内存中.)

Loading everything and just selecting afterwards is not a solution (the file is super big, it doesn't fit in memory).

推荐答案

我将使用包data.table，然后使用fread()指定要通过参数select或drop保留/删除的列.来自?fread

I will use package data.table and then with fread() specify columns to keep/drop by arguments selector drop. From ?fread

选择要保留的列名称或数字的向量，其余部分删除.

select Vector of column names or numbers to keep, drop the rest.

drop要删除的列名或数字的向量，其余部分保留.

drop Vector of column names or numbers to drop, keep the rest.

最好！

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