英文:
Outputting contents generated from loops into one column or list per loop
问题
Here is the translated code part you requested:
我不是一个编程专家，但我正在尝试学习R，同时处理我的数据。我想要创建一个循环，以便遍历每一列，并输出这些列中最高值的行名称（按从最高值到最低值的顺序）。我特别想要创建一个循环，而不是手动逐列处理，因为我的数据集有很多列，我真的想学会使用循环。这是我的示例数据：
```R
mydata <- data.frame(
rownames = c("fifth", "second", "third", "first", "fourth"),
value_1 = c(0, 10, 3, 20, 1),
value_2 = c(10, 20, 13, 30, 11),
value_3 = c(5, 15, 8, 25, 6)
) %>% remove_rownames %>% column_to_rownames(var = "rownames")
对于输出，我希望得到一个表格，其中每一列都有行名称，按每列中最高值到最低值的顺序排列。或者，甚至为每一列创建一个单独的“列表”也可以。
表格示例输出：
| value_1 | value_2 | value_3 |
|---|---|---|
| first | first | first |
| second | second | second |
| third | third | third |
| fourth | fourth | fourth |
"列表"示例输出：
> value_1
[1] "first" "second" "third" "fourth" "fifth"
> value_2
[1] "first" "second" "third" "fourth" "fifth"
> value_3
[1] "first" "second" "third" "fourth" "fifth"
我的尝试使用top_n(4, i)来返回每列中最高的4个值的行名称，但它没有按值的高低顺序排列行名称。我尝试通过首先使用arrange(desc(i))将行按值从高到低排序来解决这个问题。
for (i in colnames(mydata)){
mydata[, i] <- arrange(mydata, desc(i)) %>% rownames_to_column() %>% top_n(4, i) %>% pull(rowname)
}
这导致了以下错误消息：
Error in UseMethod("arrange") : no applicable method for 'arrange' applied to an object of class "c('integer', 'numeric')"
即使arrange起作用，我也不知道如何将每个循环的结果输出到单独的列或值。
帮助？
Please note that the code is provided as-is, and it may require further adjustments to work correctly in your R environment.
<details>
<summary>英文:</summary>
I am not a coder but I am trying to learn R while I process my data. I want to make a loop to go through each column and output the row names of the highest values in those columns (in order of highest value to lowest value). I specifically want to make a loop instead of doing it manually column-by-column because my dataset has a lot of columns and I really want to learn loops. Here is my example data:
mydata <- data.frame (rownames = c("fifth", "second", "third", "first", "fourth"),
value_1 = c(0,10,3,20,1),
value_2 = c(10,20,13,30,11),
value_3 = c(5,15,8,25,6)
) %>% remove_rownames %>% column_to_rownames(var="rownames")
For the output, I would love a table where each column has the row names in order of highest value to lowest value for each column in mydata. Alternately, even a separate "list" for each column would be fine.
example output as a table:
| value_1 | value_2 | value_3 |
| -------- | -------- | -------- |
| first | first | first |
| second | second | second |
| third | third | third |
| fourth | fourth | fourth |
example output as "lists":
> value_1
[1] "first" "second" "third" "fourth" "fifth"
> value_2
[1] "first" "second" "third" "fourth" "fifth"
> value_3
[1] "first" "second" "third" "fourth" "fifth"
my attempt at a loop uses top_n(4, i) to return the row names of the highest 4 values in each column, but it doesn't put the row names in order of how high the value is. I tried to solve this by first sorting the rows by highest to lowest value with arrange(desc(i)).
> for (i in colnames(Sample_Ordering_Table)){
data[,i] <- arrange(desc(i)) %>% rownames_to_column() %>% top_n(4, i) %>% pull(rowname)
}
this resulted in the following error message
Error in UseMethod("arrange") :
no applicable method for 'arrange' applied to an object of class "c('integer', 'numeric')"
Even if the arrange did work, I don't know how to output the results of each loop to a separate column or value.
Help?
</details>
# 答案1
**得分**: 1
以下是翻译好的部分：
"While this can be done without a loop, it sounds like you'd like to fix your current loop solution." => "虽然这可以在没有循环的情况下完成，但听起来你想修复你当前的循环解决方案。"
"The first argument of `arrange` is the data.frame, which is missing (often we pipe this in and don't think about it). You provide column names through `i` in your loop, but not `mydata`. So that should be added." => "`arrange`的第一个参数是数据框，这个参数缺失了（通常我们使用管道传递它，不去考虑它）。你通过循环中的`i`提供了列名，但没有提供`mydata`。所以应该添加它。"
"Second, `i` is a character value, not a symbol. So you can use the `.data` pronoun with `i` to access the column within `mydata`." => "其次，`i`是一个字符值，不是一个符号。因此，你可以使用`.data`代词和`i`来访问`mydata`中的列。"
"This example stores the result in a list." => "这个示例将结果存储在一个列表中。"
"$value_1" => "$value_1"
"[1] "first" "second" "third" "fourth" "fifth"" => "[1] "first" "second" "third" "fourth" "fifth""
"$value_2" => "$value_2"
"[1] "first" "second" "third" "fourth" "fifth"" => "[1] "first" "second" "third" "fourth" "fifth""
"$value_3" => "$value_3"
"[1] "first" "second" "third" "fourth" "fifth"" => "[1] "first" "second" "third" "fourth" "fifth""
<details>
<summary>英文:</summary>
While this can be done without a loop, it sounds like you'd like to fix your current loop solution.
The first argument of `arrange` is the data.frame, which is missing (often we pipe this in and don't think about it). You provide column names through `i` in your loop, but not `mydata`. So that should be added.
Second, `i` is a character value, not a symbol. So you can use the `.data` pronoun with `i` to access the column within `mydata`.
This example stores the result in a list.
lst <- list()
for (i in colnames(mydata)) {
lst[[i]] <- mydata %>%
arrange(desc(.data[[i]])) %>%
rownames_to_column() %>%
top_n(4, i) %>%
pull(rowname)
}
**Output**
$value_1
[1] "first" "second" "third" "fourth" "fifth"
$value_2
[1] "first" "second" "third" "fourth" "fifth"
$value_3
[1] "first" "second" "third" "fourth" "fifth"
</details>
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