[英]How to get a static vector of data.table column names
我想創建一個data.table對象的名稱，使用后不會改變的不變矢量setnames 。 例如，我要創建一個mtcars.names版本，該版本將在此處使用"mpg"而不是"miles.per.gallon" ：
mtcars.dt <- data.table(mtcars)
(mtcars.names <- names(mtcars.dt))
[1] "mpg" "cyl" "disp" "hp" "drat" "wt" "qsec" "vs" "am" "gear"
[11] "carb"
setnames(mtcars.dt, "mpg", "miles.per.gallon")
mtcars.names
[1] "miles.per.gallon" "cyl" "disp" "hp"
[5] "drat" "wt" "qsec" "vs"
[9] "am" "gear" "carb"
mtcars.names <- copy(names(mtcars.dt))
setnames(mtcars.dt, "mpg", "miles.per.gallon")
mtcars.names
## [1] "mpg" "cyl" "disp" "hp" "drat" "wt" "qsec" "vs" "am" "gear"
## [11] "carb"
data.table：如何將字符向量傳遞給函數 get data.table 以將其內容視為列名？
[英]data.table: How do I pass a character vector to a function get data.table to treat its contents as column names?
使用列名的字符向量訪問data.table中的列
[英]Accessing columns in data.table using a character vector of column names
R data.table：如何通過引用作為向量提供的列名來更新行？
[英]R data.table: How to update rows by reference with column names supplied as vector?
如何根據列名的字符向量對 i 中的 data.table 進行子集化（例如查找 NA）
[英]How to subset a data.table in i (eg finding NAs) based on a character vector of column names
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