Context: I want to add cumulative sum column to my tibble named words_uni. I used library(dplyr), function mutate. I work with R version 3.4.1 64 bit - Windows 10 and RStudio Version 1.0.143
> head(words_uni)
# A tibble: 6 x 3
# Groups: Type [6]
Type Freq per
<chr> <int> <dbl>
1 the 937839 0.010725848
2 i 918552 0.010505267
3 to 788892 0.009022376
4 a 615082 0.007034551
Then I did the following:
> words_uni1 = words_uni %>%
mutate( acum= cumsum(per))
> head(words_uni1)
# A tibble: 6 x 4
# Groups: Type [6]
Type Freq per acum
<chr> <int> <dbl> <dbl>
1 the 937839 0.010725848 0.010725848
2 i 918552 0.010505267 0.010505267
3 to 788892 0.009022376 0.009022376
4 a 615082 0.007034551 0.007034551
Problem: It is not doing what I was expecting, and I cannot see why.
I would appreciate your comments. Thanks in advance.