Conditional Indicator based on row number-CodePudding

i have this data frame below. I want to make a column, where if ind_2 = 1 first, before any of the other rows, then put a 1.

row number	ind_1	ind_2	ind_3
1	0	0	0
2	0	1	0
3	1	0	0
4	0	1	1

desired output:

row number	ind_1	ind_2	ind_3	master_ind
1	0	0	0	0
2	0	1	0	1
3	1	0	0	0
4	0	1	1	0

CodePudding user response：

You could check which row has the first value with 1 and check based on the row_number if it needs to return a 1 or 0 like this:

library(dplyr)
df %>%
  mutate(master_ind = ifelse(row_number() == min(which(ind_2 == 1)), 1, 0))
#>   row_number ind_1 ind_2 ind_3 master_ind
#> 1          1     0     0     0          0
#> 2          2     0     1     0          1
#> 3          3     1     0     0          0
#> 4          4     0     1     1          0

^{Created on 2023-01-25 with reprex v2.0.2}

CodePudding user response：

We may use base R to do this

df1$master_ind <-  ( df1[,2] == 0 &
     apply(df1[-1], 1, \(x) sum(cumsum(x[-1] == 1) == 1)) > 1
)

-output

 df1
  rownumber ind_1 ind_2 ind_3 master_ind
1         1     0     0     0          0
2         2     0     1     0          1
3         3     1     0     0          0
4         4     0     1     1          0

data

df1 <- structure(list(rownumber = 1:4, ind_1 = c(0L, 0L, 1L, 0L), ind_2 = c(0L, 
1L, 0L, 1L), ind_3 = c(0L, 0L, 0L, 1L)), row.names = c(NA, -4L
), class = "data.frame")

CodePudding user response：

You can use match:

df1 %>% 
  mutate(master_ind =  (rownumber == match(1, df1$ind_2)))

  rownumber ind_1 ind_2 ind_3 master_ind
1         1     0     0     0          0
2         2     0     1     0          1
3         3     1     0     0          0
4         4     0     1     1          0