Export data.table:::uniqlist for external use

[anhqle]

uniqlist is useful to detect whether there's a change in value in an R's data frame. (For example, check if a variable change values in time series data.)

See this StackOverflow question, which shows that there's no readable alternative to uniqlist

x = data.frame(cnt=1:10, code=rep('ELEMENT 1',10), val0=rep(5,10),  val1=rep(6,10),val2=rep(3,10))
x[4,]$val0=6

data.table:::uniqlist(x[, 3:5])
# [1] 1 4 5

[jangorecki]

just for you information here is an alternative way to do this for time series using data.table: https://github.com/jangorecki/rChartsDygraphs/blob/master/man/dygraph.Rd#L99
it is not very readable, it might be efficient but surely not as good as data.table's solutions. I didn't even knew about uniqlist before.
Looking forward to have it exported.

[kenklin]

I was looking for this functionality and found the StackOverflow post mentioned by LaDilettante with Arun's suggestion to file an issue in GitHub. I then discovered this opened issue. I too am now using uniqlist and would like to see it exported. Thanks for the useful work.

[jangorecki]

I think we should rename this function for exporting. Current name will be confusing, as we now have rbindlist (do.call(rbind, ...)), and cbindlist and mergelist are coming to also provide corresponding reduction using cbind and merge.
If anyone has some idea for new name please put your feedback here.
According to comments in code, and reference to base::order, which mentions bash uniq, the name uniq seems reasonable.