Well, actually, concat returns a seq, not a list. For all practical purposes, it looks like a list, but it isn't one. Practically, the difference is laziness, which is a whole thing on its own. Also the count operation is linear when lists just keep track of their length, and can do it in constant-time.
On Wed, Jul 18, 2018 at 11:17 AM Christian Seberino <cseber...@gmail.com> wrote: > Actually I was just kicked out of paradise. concat always returns a list > and does NOT return a vector for this (concat [1 2] [3 4]) sadly. > > cs > > _______________________________________ > > Christian Seberino, Ph.D. > Phone: (936) 235-1139 > Email: cseber...@gmail.com > _______________________________________ > > > > On Wed, Jul 18, 2018 at 2:16 AM, Didier <didi...@gmail.com> wrote: > >> It's never a good idea to use the wrong data structure for the job. >> >> And thus Clojure takes the stance that it won't make bad ideas easy for >> you to use. Yet, it will never prevent you from doing anything. >> >> If you want to do something bad, you'll need to get your own hands dirty. >> >> That's why slow data structure access functions don't exist as standard. >> That's why data transforms are lazy by default. And why the non lazy >> variant (transducers) do loop fusion for you. That's why mutability is ugly >> and requires you to wrap things in extra verbosity. That's why OOP isn't >> there, and forces you to use the host interop if you want it. That's why >> there's only recursive loops. Etc. >> >> The Clojure standard lib is opinionated. It's not trying to make >> everything easy and convenient. It's trying to make things simple to reason >> about, and promote Rich Hickeys opinion of what is a good idea, and what >> isn't. >> >> But, it can afford to be this way, because it made itself a Lisp, meaning >> it gave you all the power needed to disagree and make your own core, which >> follows your own opinions of good and bad.[1] >> >> Now, I recommend that everyone should have a core library of their own >> that they keep around for cases like this, where they disagree. >> >> And for beginners, I mean, what are you trying to teach them? What >> problem requires them to add items to the beginning and end of an ordered >> collection? >> >> Anyways, my advice is to teach them concat. It's even nicer then >> append/prepend. You just give it the arguments where you want them to go. >> >> (concat [1] [2 3]) >> >> (concat [1 2] [3]) >> >> And it works for any type of ordered collections, even arrays. >> >> Also, this blog I think does a great job at teaching all this to a >> beginner >> https://medium.com/@greg_63957/conj-cons-concat-oh-my-1398a2981eab >> >> >> >> [1] Except for reader macros. Rich didn't want you to be able to change >> the whole program syntax in unconstrained ways. That's probably a good >> thing to at least keep the foundation universal accross code bases. >> >> -- >> 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 >> --- >> You received this message because you are subscribed to the Google Groups >> "Clojure" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to clojure+unsubscr...@googlegroups.com. >> For more options, visit https://groups.google.com/d/optout. >> > > -- > 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 > --- > You received this message because you are subscribed to the Google Groups > "Clojure" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to clojure+unsubscr...@googlegroups.com. > For more options, visit https://groups.google.com/d/optout. > -- 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 --- You received this message because you are subscribed to the Google Groups "Clojure" group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
