How to make a multiple corpora in R - r

Question

This is a car review data which has more than 40,000 rows and each review has more than 500 characters. This is sample data : https://drive.google.com/open?id=1ZRwzYH5McZIP2NLKxncmFaQ0mX1Pe0GShTMu57Tac_E
| brand | review | favorite | c4 | c5 | c6 | c7 | c8 |
| brand1 | 500 characters1 | 100 characters1 | | | | | |
| brand2 | 500 characters2 | 100 Characters2 | | | | | |
| brand2 | 500 characters3 | 100 Characters3 | | | | | |
| brand2 | 500 characters4 | 100 Characters4 | | | | | |
| brand3 | 500 characters5 | 100 Characters5 | | | | | |
| brand3 | 500 characters6 | 100 characters6 | | | | | |
I'd like to merge review column by brands like this :
| Brand | review | favorite | c4 | c5 | c6 | c7 | c8 |
| brand1 | 500 characters1 | 100 characters1 | | | | | |
| brand2 | 500 characters2 | 100 Characters2 | | | | | |
| | 500 characters3 | 100 Characters3 | | | | | |
| | 500 characters4 | 100 Characters4 | | | | | |
| brand3 | 500 characters5 | 100 Characters5 | | | | | |
| | 500 characters6 | 100 characters6 | | | | | |
So, I tired to use aggregate().
temp <- aggregate(data$review ~ data$brand , data, as.list )
But, It takes very long.
Is there any simple way to merge that?
Thank you in advance!

Answer 1

Try splitting them on each factor and then pasting them together. aggregate() is a horribly slow function and should be avoided for all but the smallest datasets.
This should do the trick: (note I downloaded your Google file as sampleDF.csv here)
sampleDF <- read.csv("~/Downloads/sampleDF.csv", stringsAsFactors = FALSE)
# aggregate text by brand
brand.split <- split(sampleDF$text, as.factor(sampleDF$Brand))
brand.grouped <- sapply(brand.split, paste, collapse = " ")
# aggregate favorite by brand
favorite.split <- split(sampleDF$favorite, as.factor(sampleDF$Brand))
favorite.grouped <- sapply(favorite.split, paste, collapse = " ")
newDf <- data.frame(brand = names(brand.split),
text <- favorite.grouped,
favorite <- favorite.grouped,
stringsAsFactors = FALSE)
If you want to bring in other variables they will need to vary at the brand level only.