从一开始就创造延伸

Question

我遇到了一个小问题。

我有一个如下所示的 table，我想创建一个包含 1 个值的 "streches" 的新列，直到找到下一个 2。

我应该创建一个：对于（1:totalnbofrow 中的行）{}？有没有更简单的方法？

  Filen Nb  Valu    Valu2   Phase
  File1 01  18.71   2.84    
  File1 02  18.68   2.85    
  File1 03  18.65   2.85    1
  File1 04  18.62   2.86    
  File1 05  18.59   2.86    
  File1 06  18.56   2.86    
  File1 07  18.52   2.86    2
  File1 08  18.49   2.86    
  File1 09  18.46   2.86    
  File1 10  18.44   2.86    
  File1 11  18.41   2.85    1
  File1 12  18.38   2.86    
  File2 01  18.36   2.86    
  File2 02  18.34   2.86    1
  File2 03  18.32   2.85    
  File2 04  18.30   2.86    2
  File2 05  18.32   2.85    
  File2 06  18.32   2.85    1
  File2 07  18.30   2.86

预期输出

  Filen Nb  Valu    Valu2   Phase
  File1 01  18.71   2.84    
  File1 02  18.68   2.85    
  File1 03  18.65   2.85    1
  File1 04  18.62   2.86    1
  File1 05  18.59   2.86    1
  File1 06  18.56   2.86    1
  File1 07  18.52   2.86    2
  File1 08  18.49   2.86    2
  File1 09  18.46   2.86    2
  File1 10  18.44   2.86    2
  File1 11  18.41   2.85    1
  File1 12  18.38   2.86    1
  File2 01  18.36   2.86    1
  File2 02  18.34   2.86    1
  File2 03  18.32   2.85    1
  File2 04  18.30   2.86    2
  File2 05  18.32   2.85    2
  File2 06  18.32   2.85    1
  File2 07  18.30   2.86    1

提前致谢

Answer 1

你可以试试

library(zoo)
df$Phase[df$Phase==''] <- NA
df$newCol <- na.locf(df$Phase, na.rm=FALSE)
df$newCol
#[1] NA NA  1  1  1  1  2  2  2  2  1  1  1  1  1  2  2  1  1

或者，如果您的预期输出与@eipi10 的解释方式相似，另一种选择是

 do.call(pmax,c(list(as.numeric(df$Phase), 1), list(na.rm=TRUE)))
 #[1] 1 1 1 1 1 1 2 1 1 1 1 1 1 1 1 2 1 1 1

或

 rowSums(cbind((df$Phase==''), as.numeric(df$Phase)), na.rm=TRUE)
 #[1] 1 1 1 1 1 1 2 1 1 1 1 1 1 1 1 2 1 1 1

或

 library(data.table)
 setDT(df)[Phase=='', Phase := '1'][]

数据

 df <- structure(list(Filen = c("File1", "File1", "File1", "File1", 
 "File1", "File1", "File1", "File1", "File1", "File1", "File1", 
 "File1", "File2", "File2", "File2", "File2", "File2", "File2", 
 "File2"), Nb = c(1L, 2L, 3L, 4L, 5L, 6L, 7L, 8L, 9L, 10L, 11L, 
 12L, 1L, 2L, 3L, 4L, 5L, 6L, 7L), Valu = c(18.71, 18.68, 18.65, 
 18.62, 18.59, 18.56, 18.52, 18.49, 18.46, 18.44, 18.41, 18.38, 
 18.36, 18.34, 18.32, 18.3, 18.32, 18.32, 18.3), Valu2 = c(2.84, 
 2.85, 2.85, 2.86, 2.86, 2.86, 2.86, 2.86, 2.86, 2.86, 2.85, 2.86, 
 2.86, 2.86, 2.85, 2.86, 2.85, 2.85, 2.86), Phase = c("", "", 
 "1", "", "", "", "2", "", "", "", "1", "", "", "1", "", "2", 
 "", "1", "")), .Names = c("Filen", "Nb", "Valu", "Valu2", "Phase"
 ), row.names = c(NA, -19L), class = "data.frame")

从一开始就创造延伸

Creating stretches from the onset

r

dataframe

数据