2010/5/19 Thomas Kjeldahl Nilsson <tho...@kjeldahlnilsson.net>: > Hello, newbie question here. :) > > I'm writing a Tetris game to teach myself Clojure, and I'm trying to > keep the code ideomatic as I go along. > One of the most basic parts of the underlying model is representing > the pieces and playing field as two dimensional matrices. > > This is an L shaped playing piece (represented by a two dimensional > vector literal): > > (def L-shape > [ > [0 1 0 0] > [0 1 0 0] > [0 1 1 0] > [0 0 0 0] > ]) > > I want to check if other matrices of same size have the same shape, > ie. are the 1's and 0's in the same places in the compared matrix? > > I suppose the most straight-forward way is write a function which > steps through the two matrices simultaneously, comparing > corresponding elements one by one. > > My question: is there a more elegant way of determining equivalence of > collection structures like these in Clojure?
Ooh yes, just use = on the two elements you want to compare: user=> (= [[0 1 0 0] [0 1 0 0]] [[1 0 0 0] [0 1 0 0]]) false user=> (= [[0 1 0 0] [0 1 0 0]] [[0 1 0 0] [0 1 0 0]]) true user=> Apart from the reference types (agents, atoms, refs, vars), every datastructure clojure provides to you has "value" semantics, not object identity semantics. And of course composing clojure datastructures preserves the "value" semantics. Welcome to the wonderful clojure world ! -- Laurent -- You received this message because you are subscribed to the Google Groups "Clojure" group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en
