shift rows above

[sai_matcha]

Data i have

id   <- c(1,1,1,2,2,2,2,3,3,4,4,4)
time <- c(0,2,4,0,4,7,10,0,5,0,3,8)
dv   <- c(NA,2,4,NA,4,8,9,NA,5,NA,6,6)
tad  <- c(1,0,3,1,2,0,5,0,1,1,6,0)

df <- data.frame(id,time,dv,tad)

if tad == 0 , i want to shift the whole row 1 step above.

please help me to do this. thank you.

[sai_matcha]

i have some factor and character columns as well in original dataset

[DavoWW]

Hi @sai_matcha,
Does this reprex do what you require?

id   <- c(1,1,1,2,2,2,2,3,3,4,4,4)
time <- c(0,2,4,0,4,7,10,0,5,0,3,8)
dv   <- c(NA,2,4,NA,4,8,9,NA,5,NA,6,6)
tad  <- c(1,0,3,1,2,0,5,0,1,1,6,0)

df <- data.frame(id,time,dv,tad)
df
#>    id time dv tad
#> 1   1    0 NA   1
#> 2   1    2  2   0
#> 3   1    4  4   3
#> 4   2    0 NA   1
#> 5   2    4  4   2
#> 6   2    7  8   0
#> 7   2   10  9   5
#> 8   3    0 NA   0
#> 9   3    5  5   1
#> 10  4    0 NA   1
#> 11  4    3  6   6
#> 12  4    8  6   0

for(ii in 2:length(df$tad)) {
  ifelse(df$tad[ii] == 0,
  df[ii-1,] <- df[ii,],
  df[ii-1,] <- df[ii-1,])
}

df
#>    id time dv tad
#> 1   1    2  2   0
#> 2   1    2  2   0
#> 3   1    4  4   3
#> 4   2    0 NA   1
#> 5   2    7  8   0
#> 6   2    7  8   0
#> 7   3    0 NA   0
#> 8   3    0 NA   0
#> 9   3    5  5   1
#> 10  4    0 NA   1
#> 11  4    8  6   0
#> 12  4    8  6   0

^{Created on 2020-11-30 by the reprex package (v0.3.0)}

This solution won't win any prizes for elegance! Would be good to see how this could be achieved in dplyr.

HTH

[zoowalk]

Could you clarify what you mean with 'shift the whole row 1 step above"? E.g. how would the first row with tad==0 have to look like eventually? Do you mean adding 1 to all the other values?

[nirgrahamuk]

my solution

id   <- c(1,1,1,2,2,2,2,3,3,4,4,4)
time <- c(0,2,4,0,4,7,10,0,5,0,3,8)
dv   <- c(NA,2,4,NA,4,8,9,NA,5,NA,6,6)
tad  <- c(1,0,3,1,2,0,5,0,1,1,6,0)

df <- data.frame(id,time,dv,tad)

library(tidyverse)

(df2<- mutate(df,orig_row_n=row_number()))

df2%>% mutate(new_row = ifelse(tad==0,orig_row_n- 1.5,
                                               orig_row_n)) %>% arrange(new_row)

   id time dv tad orig_row_n new_row
1   1    2  2   0          2     0.5
2   1    0 NA   1          1     1.0
3   1    4  4   3          3     3.0
4   2    0 NA   1          4     4.0
5   2    7  8   0          6     4.5
6   2    4  4   2          5     5.0
7   3    0 NA   0          8     6.5
8   2   10  9   5          7     7.0
9   3    5  5   1          9     9.0
10  4    0 NA   1         10    10.0
11  4    8  6   0         12    10.5
12  4    3  6   6         11    11.0

[sai_matcha]

Hi ..

1. given the condition , TAD of first row will never be zero in my case

2. assume we have row numbers for data. if row value in TAD column is zero, decrease the row number( if it is 19 , make it 18). so actual row will shift up for one step. and above row come down for one step

[sai_matcha]

Thank you.

Sorry for my late reply. I tested all the solutions. those worked very well for my data. I am just confused, to mark which one as solution .

Thank you very much for your kind help and time.

I am available if anymore clarifications are required.