Applying if function to every row in a column in r like in excel

Question

I hope i am able to explain myself well and am not asking a duplicate question.

I have a CSV file in which there is a column of sales. In that column i want to apply a logical function like if so that every row in that column is evaluated and returns the maximum value out of the selected rows. I am new to r done all my work in excel, so i am having difficulties.

Price   Price Events    Units      Sales      Sales/Event    Returned Price
2.31    1                737        1702       1702 
2.33    1                928        2162       2162          2.33
2.36    2                1660       3918       1959 
2.42    1                861        2084       2084

IN the column Sales per event i want to apply a function in which if(and(Sales_Per_Event$2>Sales_Per_Event$1 , Sales_Per_Event$2>Sales_Per_Event$3 , Price$2 , ""))

Please do not post data as images, edit your question and post the output of `dput(Sales_Per_Event)`. — Rui Barradas, Oct 15 '17 at 16:20
Including a [minimal reproducible example](https://stackoverflow.com/questions/5963269/how-to-make-a-great-r-reproducible-example) in your question will increase your chances of getting an answer. — Samuel, Oct 15 '17 at 16:33
i haven't been able try anything as of yet i was thinking of using map function from the purr package — ABHIK ARORA, Oct 15 '17 at 17:02
it returned only one price because it fulfilled the condition — ABHIK ARORA, Oct 15 '17 at 17:06

Rui Barradas · Answer 1 · 2017-10-15T17:59:59.080

I believe I finally understood your question. If not just say so.
First, the data.

dat <-
structure(list(Price = c(2.31, 2.33, 2.36, 2.42), Price_Events = c(1L, 
1L, 2L, 1L), Units = c(737L, 928L, 1660L, 861L), Sales = c(1702L, 
2162L, 3918L, 2084L), Sales_per_Event = c(1702L, 2162L, 1959L, 
2084L)), .Names = c("Price", "Price_Events", "Units", "Sales", 
"Sales_per_Event"), class = "data.frame", row.names = c(NA, -4L
))

Now, the code.

#
# Input   x - Sales_per_Event
#         y - Price
# Returns z - Returned_Price
#
abhik <- function(x, y){
    n <- length(x)
    z <- numeric(n)
    z[1] <- NA
    z[n] <- NA
    for(i in seq_along(x)[-c(1, n)]){
        if(x[i] > x[i - 1] && x[i] > x[i + 1])
            z[i] <- y[i]
        else
            z[i] <- NA
    }
    z
}

abhik(dat$Sales_per_Event, dat$Price)
#[1]   NA 2.33   NA   NA

dat$Returned_Price <- abhik(dat$Sales_per_Event, dat$Price)
dat

Note that I have opted for NA instead of blank character values because blanks would transform your entire column into character or, worse, factors.

Thanks a lot its working, really appreciate it. Just need to understand the function myself now. — ABHIK ARORA, Oct 15 '17 at 17:37
Input `dat$Sales_per_Event` as `x` and `dat$Price` as `y`. It returns the new column, `dat$Returned_Price`. Maybe I should write this in the answer? — Rui Barradas, Oct 15 '17 at 17:43

Applying if function to every row in a column in r like in excel

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