How to create a column to indicate other columns type in r

Question

I want to create a new column to indicate the fuel type base on the previous fuel data, but I have no idea how to do that. Pleas help! Thanks

Answer 1

First, please take a look at the resources provided in the comments above on how to ask good questions here. It is sometimes a pain to set up a good question, but it really goes a long way towards getting your question answered quickly and effectively.

That aside, here's a stab at what I think you are asking for.

First, let's create a simple, reproducible data set (i.e. anybody can run this code to create the same data set, which means we're all starting from the same point):

df <- data.frame( fuel12 = c(100,0,0,100,0)
                , fuel34 = c(0,100,0,100,0)
                , fuel56 = c(0,0,100,0,0)
                )
#     fuel12 fuel34 fuel56
# 1    100      0      0
# 2      0    100      0
# 3      0      0    100
# 4    100    100      0
# 5      0      0      0

Next, we'll use apply to look for any non-zero values within the columns of df. If there are no non-zero values, then the column will say None. I'm not sure if multiple non-zero columns is a possibility, but just in case we'll have all non-zero columns listed and delimited with a comma (e.g. fuel12,fuel34).

df$which_fuel <- apply(df, 1, function(x) { ifelse(sum(x)==0
                                                  , "None"
                                                  , paste(names(df)[x > 0], collapse=",")
                                                  )})
df
#   fuel12 fuel34 fuel56    which_fuel
# 1    100      0      0        fuel12
# 2      0    100      0        fuel34
# 3      0      0    100        fuel56
# 4    100    100      0 fuel12,fuel34
# 5      0      0      0          None

Is this what you were looking for?