Hi R-devel, I have noticed a discrepancy between is.list() and is(x, ?list?), which I previously believed to be synonymous. On R version 3.5.2 (2018-12-20): data(iris) is.list(iris) # TRUE is(iris, ?list?) # FALSE Is this discrepancy intentional? Kind regards, Shian Su _______________________________________________ The information in this email is confidential and intended solely for the addressee. You must not disclose, forward, print or use it without the permission of the sender. The Walter and Eliza Hall Institute acknowledges the Wurundjeri people of the Kulin Nation as the traditional owners of the land where our campuses are located and the continuing connection to country and community. _______________________________________________ [[alternative HTML version deleted]]