修复多个警告“未知列” [英] Fixing a multiple warning "unknown column"

问题描述

对于所有类型的命令（例如，str（x））在安装软件包上进行更新时，我都会持续存在未知列警告，并且不知道如何调试或修复它。

I have a persistent multiple warning of "unknown column" for all types of commands (e.g., str(x) to installing updates on packages), and not sure how to debug this or fix it.

警告未知列与我重命名的tbl_df中的变量有明显的相关性，但是与tbl_df（看似无关的各种命令）例如，在包上安装更新，str（x）其中x只是一个字符向量）。

The warning "unknown column" is clearly related to a variable in a tbl_df that I renamed, but the warning comes up in all kinds of commands seemingly unrelated to the tbl_df (e.g., installing updates on a package, str(x) where x is simply a character vector).

推荐答案

我一直遇到同样的问题，虽然我不知道为什么当我们发生时，我已经能够固定下来，从而防止它发生。

I have been encountering the same problem, and although I don't know why it occurs, I have been able to pin down when it occurs, and thus prevent it from happening.

这个问题似乎是在一个基本的R数据帧中，而不是在一个字节数据帧中添加一个派生自索引的新列。以这个例子为例，在基础R数据框中添加新列（ age ）：

The issue seems to be with adding in a new column, derived from indexing, in a base R data frame vs. in a tibble data frame. Take this example, where you add a new column (age) to a base R data frame:

base_df <- data.frame(id = c(1:3), name = c("mary", "jill","steve"))

base_df$age[base_df$name == "mary"] <- 47

警告。但是当同样的事情完成了一个琐事，它会引发一个警告（因此，我认为导致奇怪的，看似无端的多重警告问题）：

That works without returning a warning. But when the same is done with a tibble, it throws a warning (and consequently, I think causing the weird, seemingly unprovoked, multiple warning issue):

library(tibble)

tibble_df <- tibble(id = c(1:3), name = c("mary", "jill","steve"))

tibble_df$age[tibble_df$name == "mary"] <- 47

Warning message:
Unknown column 'age' 

确实有更好的方法来避免这种情况，但是我发现首先创建一个 NA的向量的工作：

There are surely better ways of avoiding this, but I have found that first creating a vector of NAs does the job:

tibble_df$age <- NA

tibble_df$age[tibble_df$name == "mary"] <- 47

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