Question: Dataframe accumulative cell addition into new column

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tiriyon •

**0**wrote:Hey guys, quite new here and to programming in general. I had to make a cummulative column out of another column in my dataframe and I couldn't find help on the mattar. So after I came on a sollution I thought it would be better to post this.

My initial thought was as follows:

```
```R
x<- as.numeric(c("",
as.numeric(Tom.VS.Hagai.R1[2,4]),
sum(as.numeric(Tom.VS.Hagai.R1[2:3,4])),
sum(as.numeric(Tom.VS.Hagai.R1[2:4,4])),
sum(as.numeric(Tom.VS.Hagai.R1[2:5,4])),
sum(as.numeric(Tom.VS.Hagai.R1[2:6,4])),
sum(as.numeric(Tom.VS.Hagai.R1[2:7,4])),
sum(as.numeric(Tom.VS.Hagai.R1[2:8,4]))))
x
Tom.VS.Hagai.R1$Accumulative.Dead<-x
```
```

After wrapping my head on the matter this is the final product:

```
```R
> # 2 column 4 row dataframe, first row character second row numeric
> name<- c("Tom", "Hagai", "Yoni", "Aviv")
> apples<- c(1, 2, 3, 4)
> DF<- data.frame(name, apples)
> DF
name apples
1 Tom 1
2 Hagai 2
3 Yoni 3
4 Aviv 4
>
> # Looping
> # y is a vector place holder for the "for" loop
> # i is a running index set to run from 1 to the length of the data.frame's column number 2.
> # in the loop, append, appends the sum of 1 to i in column 2 of the data.frame.
>
> y<-c()
> for( i in 1:length(DF[,2])){
+ y<- append(y, sum(DF[1:i,2]))
+ }
>
> # Next we load the new vector y as a third column of the datafre:
> DF$accumulative<- y
> DF
name apples accumulative
1 Tom 1 1
2 Hagai 2 3
3 Yoni 3 6
4 Aviv 4 10
```
```

Hope it helped someone somewhere, enjoy.

(edited: Spelling mistake in heading)

did you try

`cumsum`

? @ tiriyon13kHey, that looks much easier, I saw the comment on stackoverflow first so added it as answer; thanks for the help!

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