数据框列命名

发布于 2024-12-04 07:44:42 字数 190 浏览 0 评论 0原文

我正在创建一个像这样的简单数据框：

qcCtrl <- data.frame("2D6"="DNS00012345", "3A4"="DNS000013579")

我的理解是列名称应该是“2D6”和“3A4”，但它们实际上是“X2D6”和“X3A4”。为什么要添加 X 以及如何停止这种情况？

原文

I am creating a simple data frame like this:

qcCtrl <- data.frame("2D6"="DNS00012345", "3A4"="DNS000013579")

My understanding is that the column names should be "2D6" and "3A4", but they are actually "X2D6" and "X3A4". Why are the X's being added and how do I make that stop?

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吃兔兔 2024-12-11 07:44:42

我不建议使用以数字开头的列名称，但如果您坚持，请使用 data.frame 的 check.names=FALSE 参数：

qcCtrl <- data.frame("2D6"="DNS00012345", "3A4"="DNS000013579", 
            check.names=FALSE)
qcCtrl

          2D6          3A4
1 DNS00012345 DNS000013579

我谨慎的原因之一与此相反，$ 运算符的使用变得更加棘手。例如，以下内容会失败并出现错误：

> qcCtrl$2D6
Error: unexpected numeric constant in "qcCtrl$2"

要解决此问题，无论何时使用列名，都必须将其括在反引号中：

> qcCtrl我不建议使用以数字开头的列名称，但如果您坚持，请使用 data.frame 的 check.names=FALSE 参数：
qcCtrl <- data.frame("2D6"="DNS00012345", "3A4"="DNS000013579", 
            check.names=FALSE)
qcCtrl

          2D6          3A4
1 DNS00012345 DNS000013579

我谨慎的原因之一与此相反，$ 运算符的使用变得更加棘手。例如，以下内容会失败并出现错误：
> qcCtrl$2D6
Error: unexpected numeric constant in "qcCtrl$2"

要解决此问题，无论何时使用列名，都必须将其括在反引号中：
2D6`
[1] DNS00012345
Levels: DNS00012345

I do not recommend working with column names starting with numbers, but if you insist, use the check.names=FALSE argument of data.frame:

qcCtrl <- data.frame("2D6"="DNS00012345", "3A4"="DNS000013579", 
            check.names=FALSE)
qcCtrl

          2D6          3A4
1 DNS00012345 DNS000013579

One of the reasons I caution against this, is that the $ operator becomes more tricky to work with. For example, the following fails with an error:

> qcCtrl$2D6
Error: unexpected numeric constant in "qcCtrl$2"

To get round this, you have to enclose your column name in back-ticks whenever you work with it:

> qcCtrlI do not recommend working with column names starting with numbers, but if you insist, use the check.names=FALSE argument of data.frame:
qcCtrl <- data.frame("2D6"="DNS00012345", "3A4"="DNS000013579", 
            check.names=FALSE)
qcCtrl

          2D6          3A4
1 DNS00012345 DNS000013579

One of the reasons I caution against this, is that the $ operator becomes more tricky to work with. For example, the following fails with an error:
> qcCtrl$2D6
Error: unexpected numeric constant in "qcCtrl$2"

To get round this, you have to enclose your column name in back-ticks whenever you work with it:
2D6`
[1] DNS00012345
Levels: DNS00012345