R中的宽到长格式

下面是我的数据集的一个片段：

> head(df)
Product   Region  Sector      Type       Date     Value
Product A Capital Primary Continued 2012-01-01      395
Product C Capital Primary Continued 2012-01-01       37
Product D Capital Primary Continued 2012-01-01      208
Product A Central Primary Continued 2012-01-01      343
Product C Central Primary Continued 2012-01-01        1
Product D Central Primary Continued 2012-01-01       80

> tail(df)
   Product   Region  Sector Type      Date    Value
Product C Southern Unknown  New 2014-12-01       11
Product D Southern Unknown  New 2014-12-01       18
Product A  Zealand Unknown  New 2014-12-01       19
Product B  Zealand Unknown  New 2014-12-01       10
Product C  Zealand Unknown  New 2014-12-01        9
Product D  Zealand Unknown  New 2014-12-01        6

我有12个日期，从2012-01-01到2014-12-01，以及几个变量因素。我想在此数据集上进行推断，即在2014-12-01之后添加一些额外的随机观察。我最初的想法是使用dcast，例如：

dcast(df, Date ~ Product + Region + Type + Sector)

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为了得到所有因素的组合。这将产生一个包含12行（日期）和118列（所有因素的组合）的数据框。然后，我可以向这个数据帧添加一些行，然后使用melt将其转换回来。但这似乎不可能。还有其他方法吗？

您可以使用

rbind

-只需确保变量名称相同：

df <- data.frame(Product = c("Product A", "Product B", "Product C"), Region = c("Capital", "Capital", "Capital"), 
              Sector = c("Primary", "Primary", "Primary"), Type = c("Continued", "Continued", "Continued"),
              Date = c("2012-01-01", "2013-01-01", "2014-12-01"), Value = c(397, 3, 456))


newdata <- data.frame(Product = c("Product A", "Product B", "Product C"), Region = c("Capital", "Capital", "Capital"), 
                  Sector = c("Primary", "Primary", "Primary"), Type = c("Continued", "Continued", "Continued"),
                  Date = c("2014-12-01", "2014-12-02", "2014-12-03"), Value = c(1, 2, 3))


all(colnames(df) == colnames(newdata))
[1] TRUE


combined <- rbind(df, newdata)

combined

    Product  Region  Sector      Type       Date Value
1 Product A Capital Primary Continued 2012-01-01   397
2 Product B Capital Primary Continued 2013-01-01     3
3 Product C Capital Primary Continued 2014-12-01   456
4 Product A Capital Primary Continued 2014-12-01     1
5 Product B Capital Primary Continued 2014-12-02     2
6 Product C Capital Primary Continued 2014-12-03     3

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df为什么不创建一个新的数据集并将它们绑定在一起？@Heroka这似乎是一个很好的解决方案-不知道为什么我没有想到这一点。谢谢