如何根據R中其他列中的值使列值唯一？

Question

我有一個類似於以下示例中所示的大型數據集。

df <- structure(list(FCN = structure(c(1L, 1L, 1L, 2L, 2L, 3L, 3L, 
3L), .Label = c("010.X91116.3D3.A8", "010.X91116.6B7.F9", "010.X91116.6C6.C12" 
), class = "factor"), DOM = structure(c(1L, 2L, 2L, 1L, 2L, 1L, 
2L, 2L), .Label = c("VH", "VK"), class = "factor"), FN = structure(c(1L, 
1L, 1L, 1L, 1L, 1L, 1L, 1L), .Label = "OM", class = "factor"), 
    RV = c(49257.4, 23571.2, 24115.6, 49351.4, 24102.6, 49641.8, 
    23226.2, 23408.2)), .Names = c("FCN", "DOM", "FN", "RV"), class = "data.frame", row.names = c(NA, 
-8L)) 

我想創建一個表，通過使FN列值基於FCN，RV和DOM中的值的後綴唯一。我可以使用for循環並處理數據，如圖所示。但是，處理數千行需要時間。

最後，我想旋轉數據，將FN中的值作爲RV中的列和值。如果可能的話，請指導我如何使用某些庫函數來優雅地實現結果。

library(reshape2) 
pivot_df <- dcast(df, FCN + DOM ~ FN) 

Answer 1

採用@ akrun的使用意見建議：

library(reshape2) 
df <- structure(list(FCN = structure(c(1L, 1L, 1L, 2L, 2L, 3L, 3L, 3L), .Label = c("010.X91116.3D3.A8", "010.X91116.6B7.F9", "010.X91116.6C6.C12"), class = "factor"), DOM = structure(c(1L, 2L, 2L, 1L, 2L, 1L, 2L, 2L), .Label = c("VH", "VK"), class = "factor"), FN = structure(c(1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L), .Label = "OM", class = "factor"), RV = c(49257.4, 23571.2, 24115.6, 49351.4, 24102.6, 49641.8, 23226.2, 23408.2)), .Names = c("FCN", "DOM", "FN", "RV"), class = "data.frame", row.names = c(NA, -8L)) 
df$FN <- with(df, paste0(FN, ave(seq_along(FN), FCN, DOM, FUN = seq_along))) 
pivot_df <- dcast(df, FCN + DOM ~ FN) 

Answer 2

我們可以使用ave做到這一點

df$FN <- with(df, paste0(FN, ave(seq_along(FN), FCN, DOM, FUN = seq_along))) 

如果我們需要重塑，以 '寬'，然後rowid從data.table可以dcast

library(data.table) 
dcast(setDT(df), FCN + DOM ~FN + rowid(DOM), value.var = "RV")