Here is an example showing 10 minutes reduced to 1 second (from NEWS on homepage). It’s like subassigning to a data.frame but doesn’t copy the entire table each time. m = matrix(1,nrow=100000,ncol=100) DF = as.data.frame(m) DT = as.data.table(m) system.time(for (i in 1:1000) DF[i,1] <- i) user system elapsed 287.062 302.627 591.984 system.time(for (i in 1:1000) … Read more
Updated answer In the context of the question, we are dealing with pseudocode, but starting in Python 3.8, := is actually a valid operator that allows for assignment of variables within expressions: # Handle a matched regex if (match := pattern.search(data)) is not None: # Do something with match # A loop that can’t be … Read more
This now works in v1.8.3 on R-Forge. Thanks for highlighting it! x <- data.table(a = 1:3, b = 1:6) f <- function(x) {list(“hi”, “hello”)} x[ , c(“col1”, “col2”) := f(), by = a][] # a b col1 col2 # 1: 1 1 hi hello # 2: 2 2 hi hello # 3: 3 3 hi … Read more
In PL/PgSQL parser, assignment operator is defined as assign_operator : ‘=’ | COLON_EQUALS ; This is a legacy feature, present in source code since 1998, when it was introduced – as we can see in the PostgreSQL Git repo. Starting from version 9.4 it is oficially documented. This idiosyncrasy – of having two operators for … Read more