creating a cumulative column for specific characters

Question

I'm just trying to calculate the cumulative accesses for both pass or fail characters in a data frame as below;

df1

df1$Passorfail   df1$accesses
Pass                   20
Pass                   30
Fail                   5
Pass                   15
Fail                   7
Fail                   10

I want R to output a table as follows;

df1$Passorfail         df1$cumaccesses
Pass                    65
Fail                    22

Answer 1

Your example is unclear (due to formating?)

I guess you want to sum by? For that you can use data.table framework:

library(data.table)
setDT(df1) # make it a data.table

# compute sum of accesses by Passorfail
df1[, cumaccesses := sum(accesses ), by = Passorfail ] 

Is that what you wanted to do?