CODEWITHSUNDEEP
r
Username
Username

Reputation: 3663

How do I make a column that sums only numeric columns?

I have a dataframe with a lot of columns.

LABEL    COL1  COL2  COL3
Meat     10    20    30
Veggies  20    30    40

How do I make column named SUMCOL that adds up COL1, COL2, COL3, and any other numeric columns I add?

Example of SUMCOL with just the above columns:

SUMCOL
60
90

Upvotes: 3

Views: 7303

Answers (3)

J.Sabree
J.Sabree

Reputation: 2546

I know this is an old post, but there's a tidy way to do this with just dplyr:

library(dplyr)

#Create dataset
data <- tibble(LABEL = c("Meat", "Veggies"),
               COL1 = c(10, 20),
               COL2 = c(20, 30),
               COL3 = c(30, 40))

data %>%
  mutate(SUMCOL = select(., starts_with("COL")) %>%
         rowSums(na.rm = TRUE))

In case anyone is unfamiliar with this syntax, it basically says "make (mutate) a new column called SUMCOL. To do so, select all columns (that's the period), but perform rowSums only on the columns that start with "COL" (as an aside, you also could list out the columns with c("COL1", "COL2", "COL3") and ignore any missing values.

Upvotes: -1

Username
Username

Reputation: 3663

I ended up using this code:

df$SUMCOL <- rowSums(df[sapply(df, is.numeric)], na.rm = TRUE)

Upvotes: 3

CPak
CPak

Reputation: 13591

You can use this function, which takes advantage of select_if and scoped argument is_numeric 

myfun <- function(df) {
               require(dplyr)
               y <- select_if(df, is_numeric)
               rowSums(y, na.rm=T)
         }

Solution

df$SUMCOL <- myfun(df)

Output

    LABEL COL1 COL2 COL3 SUMCOL
1    Meat   10   20   30     60
2 Veggies   20   30   40     90

Upvotes: 0

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