如何将 R 数据从长格式转换为宽格式 [英] How to transform R data from long-ish to wide-ish
问题描述
我正在使用 R 尝试将我的数据框从long-ish"转换为wide-ish"，但我徒劳地寻找使用结构与我的数据相似的数据的答案.这是我的数据:
I am using R to try to transform my data frame from "long-ish" to "wide-ish" and I have searched in vain for an answer that uses data similar in structure to mine. Here are my data:
| ID | NAME | V1 | V2 | V3 |
|------|------|-------|----:|-----:|
| 1001 | Bob | Red | 302 | 0.50 |
| 1001 | Bob | Blue | 737 | 0.50 |
| 1002 | Jim | Red | 432 | 0.14 |
| 1002 | Jim | Blue | 643 | 0.60 |
| 1002 | Jim | Green | 34 | 0.46 |
| 1006 | Dan | Red | 876 | 1.25 |
这就是我希望最终数据(宽)的外观:
And this is how I would like the final data (wide) to look:
| ID | NAME | V2.Red | V2.Blue | V2.Green | V3.Red | V3.Blue | V3.Green |
|------|------|-------:|--------:|---------:|-------:|--------:|---------:|
| 1001 | Bob | 302 | 737 | N/A | 0.50 | 0.50 | N/A |
| 1002 | Jim | 432 | 643 | 34 | 0.14 | 0.60 | 0.46 |
| 1006 | Dan | 876 | N/A | N/A | 1.25 | N/A | N/A |
所以，基本上，我将所有相同的 ID 行合并为一行(带有伴随的 NAME)，以便总行数等于唯一 ID 值的数量.
然后我使用 V1 的唯一值来创建尽可能多的列，因为 V1 中的唯一值乘以额外变量"的数量——V2、V3.(我有更多 V2 和 V3 类型的变量.
So, basically, I'm collapsing all of the same ID rows into one row (with accompanying NAME) so that the total number of rows is equal to the number of unique ID values.
I am then using the unique values of V1 to create as many columns as there are unique values in V1 times the number of "extra variables"--V2, V3. (I have many more variables of the V2 and V3 type.
提前致谢！
推荐答案
为了完整起见，这里是一个 data.table 解决方案
For completeness sake, here is a data.table solution
library( data.table )
dcast( setDT(df), ID + NAME ~ V1, value.var = c("V2","V3"), sep = "." )
# ID NAME V2.Blue V2.Green V2.Red V3.Blue V3.Green V3.Red
# 1: 1001 Bob 737 NA 302 0.5 NA 0.50
# 2: 1002 Jim 643 34 432 0.6 0.46 0.14
# 3: 1006 Dan NA NA 876 NA NA 1.25
这篇关于如何将 R 数据从长格式转换为宽格式的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
