Adding a Cumulative Sum Column

The magic of cumsum() is demonstrated in this post.

Suppose we have the following dataset.

library(tidyverse)

##### Creating Sample Data #####
Name <- as.character(c("Abbey", "Brian", "Connie", "Dan", "Ethan"))
GPA <- c(3.0, 2.8, 2.1, 4.0, NA)
Grade <- c(3, 4, NA, NA, 6)
State <- c("AL", NA, NA, NA, "CA")
Jello_Consumption <- c(1,2,3,4,5)

data <- data.frame(Name, GPA, Grade, State, Jello_Consumption, stringsAsFactors = FALSE)

data

library(tidyverse)

##### Creating Sample Data #####

Name <- as.character(c("Abbey", "Brian", "Connie", "Dan", "Ethan"))

GPA <- c(3.0, 2.8, 2.1, 4.0, NA)

Grade <- c(3, 4, NA, NA, 6)

State <- c("AL", NA, NA, NA, "CA")

Jello_Consumption <- c(1,2,3,4,5)

data <- data.frame(Name, GPA, Grade, State, Jello_Consumption, stringsAsFactors = FALSE)

data

> data
    Name GPA Grade State Jello_Consumption
1  Abbey 3.0     3    AL                 1
2  Brian 2.8     4  <NA>                 2
3 Connie 2.1    NA  <NA>                 3
4    Dan 4.0    NA  <NA>                 4
5  Ethan  NA     6    CA                 5

> data

Name GPA Grade State Jello_Consumption

1 Abbey 3.0 3 AL 1

2 Brian 2.8 4 <NA> 2

3 Connie 2.1 NA <NA> 3

4 Dan 4.0 NA <NA> 4

5 Ethan NA 6 CA 5

We can add a cumulative Jello consumption column using cumsum() .

##### Cumsum #####
data <- mutate(data, Cumulative = cumsum(Jello_Consumption))

data

##### Cumsum #####

data <- mutate(data, Cumulative = cumsum(Jello_Consumption))

data

> data
    Name GPA Grade State Jello_Consumption Cumulative
1  Abbey 3.0     3    AL                 1          1
2  Brian 2.8     4  <NA>                 2          3
3 Connie 2.1    NA  <NA>                 3          6
4    Dan 4.0    NA  <NA>                 4         10
5  Ethan  NA     6    CA                 5         15

> data

Name GPA Grade State Jello_Consumption Cumulative

1 Abbey 3.0 3 AL 1 1

2 Brian 2.8 4 <NA> 2 3

3 Connie 2.1 NA <NA> 3 6

4 Dan 4.0 NA <NA> 4 10

5 Ethan NA 6 CA 5 15