FYI, R actually allows the use of = as the assignment operation. In fact within mutate in tidyverse world, you use it extensively to create columns in matrix like objects called data frames. We tend towards the usage of the arrow -&gt; in many cases now. But there is no where in the language where you can't entirely replace an arrow with an equals sign. Also like most languages we always use double equals, == as a check for equivalence,(reply>), @Leo Gama great minds :) AFAIK it's actually defined internal to data table as Matt Dowles 'invention'. A little like the pipe %&gt;% is in magrittr, though in that case most of tidyverse imports it from there, so it can feel like it's part of the parser as well :),(reply>), And the data.table package uses the (defined in the language/parser but unused?) walrus operator for "column assignments" in its expressions!<br><br>(edit: just sow your second comment...),(reply>), Also in R, we've actually had the walrus operator in data.table for almost a decade.