If you want to be able to arbitrarily manipulate your data structures, you should look at Specter. I recommend reading my introductory blog post on it: http://nathanmarz.com/blog/clojures-missing-piece.html The `BEFORE-ELEM` and `AFTER-ELEM` navigators are what you use for prepending/appending.
Things get a lot worse in Clojure when dealing with nested/recursive data structures. These use cases were the main motivators for developing Specter, and the navigation concept naturally ended up solving the more basic manipulations like prepend / append / mid-sequence insertion. On Wednesday, July 18, 2018 at 11:21:32 AM UTC-4, Gary Trakhman wrote: > > 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 <cseb...@gmail.com > <javascript:>> 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: cseb...@gmail.com <javascript:> >> _______________________________________ >> >> >> >> On Wed, Jul 18, 2018 at 2:16 AM, Didier <did...@gmail.com <javascript:>> >> 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 clo...@googlegroups.com >>> <javascript:> >>> Note that posts from new members are moderated - please be patient with >>> your first post. >>> To unsubscribe from this group, send email to >>> clojure+u...@googlegroups.com <javascript:> >>> 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+u...@googlegroups.com <javascript:>. >>> 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 clo...@googlegroups.com >> <javascript:> >> Note that posts from new members are moderated - please be patient with >> your first post. >> To unsubscribe from this group, send email to >> clojure+u...@googlegroups.com <javascript:> >> 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+u...@googlegroups.com <javascript:>. >> 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.
