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rdummy-variable

Create Dummy Variable if NA 1 else -1

I want to create a dummy where all cells that include NA become 1 and all other cells -1. I tried to different things both not resulting in my desired outcome.

1) This leads to only NA Values. 

Cox.Reg$FirstTask <- ifelse(Cox.Reg$active_task_avg_depth == NA, 1, -1)

2) This leads to only the -1 values being shown in the new column.

Cox.Reg$FirstTask <- ifelse(Cox.Reg$active_task_avg_depth == "NA", 1, -1)
Solution

  • If it is a real NA, then we can use is.na to detect the NA elements, which would return TRUE for all NA and FALSE for others as a logical vector, which can be used in ifelse to change the values

    ifelse(is.na(Cox.Reg$active_task_avg_depth), 1, -1)

    Or another option is to create a numeric index and change the values accordingly

    c(-1, 1)[is.na(Cox.Reg$active_task_avg_depth) + 1]