Re: trouble using nested map fn
I'm glad my question generated so much discussion! Thank you all for the suggestions...it's all good stuff trying to wrap my head around and improve my facility with clojure. On Aug 24, 1:27 am, Meikel Brandmeyer m...@kotka.de wrote: Hi, On 24 Aug., 03:08, gary ng garyng2...@gmail.com wrote: (map #(for [s %2] (map * %1 s)) target signal) Though personally I still think the %2 %1 is a bit confusing.- Zitierten Text ausblenden - If you don't like it, don't use it.You can always give things meaningful names. (for [[signals target] (map vector signals-list target-list) signal signals] (map * signal target)) Sincerely Meikel -- 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
trouble using nested map fn
I am trying to write a fn to correlate 2 signals using 3 nested map fn. I have 2 collections of data. THe first group of signals called target looks something like this. target: ( (1,2,3,4) (2,3,4,5) ...) The second collection is called signal and looks like this: signal: ( ((1,2,3,4)(2,3,4,5)(3,4,5,6)) ((2,3,4,5)(3,4,5,6)(4,5,6,7)) ... ) I would like to take the first list in target and multiply it by every list in the first group of signal. And then continue on processing the second list, etc... which would result in something like: ( ((1,4,9,16)(2,6,12,20)(3,8,15,24)) ((4,9,16,25) (6,12,20,30) (8,15,24,35)) ... ) I try a nested map fns like this, but can't get it to work: (map #(map #(map * %1 %2) %1 %2) target signal) -- 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
Re: trouble using nested map fn
On Mon, 23 Aug 2010 17:26:44 +0200, Glen Rubin rubing...@gmail.com wrote: I am trying to write a fn to correlate 2 signals using 3 nested map fn. I have 2 collections of data. THe first group of signals called target looks something like this. target: ( (1,2,3,4) (2,3,4,5) ...) The second collection is called signal and looks like this: signal: ( ((1,2,3,4)(2,3,4,5)(3,4,5,6)) ((2,3,4,5)(3,4,5,6)(4,5,6,7)) ... ) I would like to take the first list in target and multiply it by every list in the first group of signal. And then continue on processing the second list, etc... which would result in something like: ( ((1,4,9,16)(2,6,12,20)(3,8,15,24)) ((4,9,16,25) (6,12,20,30) (8,15,24,35)) ... ) I try a nested map fns like this, but can't get it to work: (map #(map #(map * %1 %2) %1 %2) target signal) It's not about nested maps, but about nested anonymous functions: if you nest anonimous functions you must use (fn [] ...) like: (map (fn [t s] (map #(map * %1 %2) t s)) target signal) -- 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
Re: trouble using nested map fn
On Mon, Aug 23, 2010 at 8:31 AM, Luka Stojanovic li...@magrathea.rs wrote: It's not about nested maps, but about nested anonymous functions: if you nest anonimous functions you must use (fn [] ...) like: (map (fn [t s] (map #(map * %1 %2) t s)) target signal) This has me question, how useful the #(...) form is as clojure's lambda form i.e. (fn [t s] ...) is already very clean and it conveys more information of what it is than the relatively cryptic %1 %2 ... -- 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
Re: trouble using nested map fn
Ah, so this is the context for your previous thread about multiplying lists. Re-using some of the code from that thread: (def target [[1 2 3 4] [2 3 4 5]]) (def signal [[[1 2 3 4] [2 3 4 5] [3 4 5 6]] [[2 3 4 5] [3 4 5 6] [4 5 6 7]]]) (defn correlate [target signal] (let [mult-lists (fn [x y] (map * x y)) mult-list-by-lists (fn [l ls] (map #(mult-lists l %) ls))] (map mult-list-by-lists target signal))) user= (correlate target signal) (((1 4 9 16) (2 6 12 20) (3 8 15 24)) ((4 9 16 25) (6 12 20 30) (8 15 24 35))) On Aug 23, 9:26 am, Glen Rubin rubing...@gmail.com wrote: I am trying to write a fn to correlate 2 signals using 3 nested map fn. I have 2 collections of data. THe first group of signals called target looks something like this. target: ( (1,2,3,4) (2,3,4,5) ...) The second collection is called signal and looks like this: signal: ( ((1,2,3,4)(2,3,4,5)(3,4,5,6)) ((2,3,4,5)(3,4,5,6)(4,5,6,7)) ... ) I would like to take the first list in target and multiply it by every list in the first group of signal. And then continue on processing the second list, etc... which would result in something like: ( ((1,4,9,16)(2,6,12,20)(3,8,15,24)) ((4,9,16,25) (6,12,20,30) (8,15,24,35)) ... ) I try a nested map fns like this, but can't get it to work: (map #(map #(map * %1 %2) %1 %2) target signal) -- 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
Re: trouble using nested map fn
uses like #(first %) keeps the code cleaner on the other hand, for more complicated things I would really not recommend the short form 2010/8/23 gary ng garyng2...@gmail.com: On Mon, Aug 23, 2010 at 8:31 AM, Luka Stojanovic li...@magrathea.rs wrote: It's not about nested maps, but about nested anonymous functions: if you nest anonimous functions you must use (fn [] ...) like: (map (fn [t s] (map #(map * %1 %2) t s)) target signal) This has me question, how useful the #(...) form is as clojure's lambda form i.e. (fn [t s] ...) is already very clean and it conveys more information of what it is than the relatively cryptic %1 %2 ... -- 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 -- Linux-user #496644 (http://counter.li.org) - first touch of linux in 2004 Demandoj en aŭ pri Esperanto? Questions about Esperanto? Vragen over Esperanto? Perguntas sobre o Esperanto? - http://demandoj.tk -- 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
Re: trouble using nested map fn
On Mon, Aug 23, 2010 at 8:50 AM, Joop Kiefte iko...@gmail.com wrote: uses like #(first %) keeps the code cleaner Is that the same as just 'first' like : (map first [[1 2] [3 4]]) (map #(first %) [[1 2] [3 4])) -- 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
Re: trouble using nested map fn
bad example =/ Yes, it is but you get the gist I hope better example: #(first (sort %)) ;) 2010/8/23 gary ng garyng2...@gmail.com: On Mon, Aug 23, 2010 at 8:50 AM, Joop Kiefte iko...@gmail.com wrote: uses like #(first %) keeps the code cleaner Is that the same as just 'first' like : (map first [[1 2] [3 4]]) (map #(first %) [[1 2] [3 4])) -- 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 -- Linux-user #496644 (http://counter.li.org) - first touch of linux in 2004 Demandoj en aŭ pri Esperanto? Questions about Esperanto? Vragen over Esperanto? Perguntas sobre o Esperanto? - http://demandoj.tk -- 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
Re: trouble using nested map fn
Again with the bad examples but... (map #(even? %) coll) is faster than (map (partial even?) coll) So it's at least got that going for it. (I know this SHOULD be written as (map even? coll)) On Aug 23, 1:59 pm, Michael Gardner gardne...@gmail.com wrote: On Aug 23, 2010, at 11:13 AM, Luka Stojanovic wrote: On Mon, 23 Aug 2010 18:01:13 +0200, Joop Kiefte iko...@gmail.com wrote: bad example =/ Yes, it is but you get the gist I hope better example: #(first (sort %)) ;) (comp first sort) and #(some-fn x %) can be written as (partial some-fn x) which leaves #(some-fn % x) as case not trivial with other syntax again (fn [y] (some-fn y x)) is about 8 chars longer, so I guess #() form really is not something that should be used that often I don't know about you, but I find #(= 2 (count %)) much nicer and easier to read than (comp (partial = 2) count). -- 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
Re: trouble using nested map fn
Really? I would be interested to hear why; is it maybe because partial has to take any number of arguments and then (apply even? args)? I've taken to using partial when I can, precisely because of the difficulty of nesting anonymous functions, and while performance isn't a big deal for me I'm curious. On Aug 23, 12:30 pm, Cameron cpuls...@gmail.com wrote: Again with the bad examples but... (map #(even? %) coll) is faster than (map (partial even?) coll) So it's at least got that going for it. (I know this SHOULD be written as (map even? coll)) On Aug 23, 1:59 pm, Michael Gardner gardne...@gmail.com wrote: On Aug 23, 2010, at 11:13 AM, Luka Stojanovic wrote: On Mon, 23 Aug 2010 18:01:13 +0200, Joop Kiefte iko...@gmail.com wrote: bad example =/ Yes, it is but you get the gist I hope better example: #(first (sort %)) ;) (comp first sort) and #(some-fn x %) can be written as (partial some-fn x) which leaves #(some-fn % x) as case not trivial with other syntax again (fn [y] (some-fn y x)) is about 8 chars longer, so I guess #() form really is not something that should be used that often I don't know about you, but I find #(= 2 (count %)) much nicer and easier to read than (comp (partial = 2) count). -- 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
Re: trouble using nested map fn
The difference is not HUGE, but in a critical section it might be a valid micro-optimization. I'd also be interested to know why, but I bet you're assumption of apply being thrown in the mix is probably pretty close to true. user= (time (dotimes [_ 1e6] (doall (map #(filter even? %) (for [i (range 0 100 4)] (range i (+ i 4))) Elapsed time: 6589.49 msecs nil user= (time (dotimes [_ 1e6] (doall (map #(filter even? %) (for [i (range 0 100 4)] (range i (+ i 4))) Elapsed time: 6620.396 msecs nil user= (time (dotimes [_ 1e6] (doall (map (partial filter even?) (for [i (range 0 100 4)] (range i (+ i 4))) Elapsed time: 8899.466 msecs nil user= (time (dotimes [_ 1e6] (doall (map (partial filter even?) (for [i (range 0 100 4)] (range i (+ i 4))) Elapsed time: 8949.646 msecs nil (sorry for further hijacking the thread) On Aug 23, 6:09 pm, Alan a...@malloys.org wrote: Really? I would be interested to hear why; is it maybe because partial has to take any number of arguments and then (apply even? args)? I've taken to using partial when I can, precisely because of the difficulty of nesting anonymous functions, and while performance isn't a big deal for me I'm curious. On Aug 23, 12:30 pm, Cameron cpuls...@gmail.com wrote: Again with the bad examples but... (map #(even? %) coll) is faster than (map (partial even?) coll) So it's at least got that going for it. (I know this SHOULD be written as (map even? coll)) On Aug 23, 1:59 pm, Michael Gardner gardne...@gmail.com wrote: On Aug 23, 2010, at 11:13 AM, Luka Stojanovic wrote: On Mon, 23 Aug 2010 18:01:13 +0200, Joop Kiefte iko...@gmail.com wrote: bad example =/ Yes, it is but you get the gist I hope better example: #(first (sort %)) ;) (comp first sort) and #(some-fn x %) can be written as (partial some-fn x) which leaves #(some-fn % x) as case not trivial with other syntax again (fn [y] (some-fn y x)) is about 8 chars longer, so I guess #() form really is not something that should be used that often I don't know about you, but I find #(= 2 (count %)) much nicer and easier to read than (comp (partial = 2) count). -- 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
Re: trouble using nested map fn
Well, #(= lo % hi) is to my mind much more readable than (fn [x] (= lo x hi)), especially embedded in another form or two (as it would be). On Aug 23, 11:48 am, gary ng garyng2...@gmail.com wrote: On Mon, Aug 23, 2010 at 8:31 AM, Luka Stojanovic li...@magrathea.rs wrote: It's not about nested maps, but about nested anonymous functions: if you nest anonimous functions you must use (fn [] ...) like: (map (fn [t s] (map #(map * %1 %2) t s)) target signal) This has me question, how useful the #(...) form is as clojure's lambda form i.e. (fn [t s] ...) is already very clean and it conveys more information of what it is than the relatively cryptic %1 %2 ... -- 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
Re: trouble using nested map fn
On Mon, Aug 23, 2010 at 8:26 AM, Glen Rubin rubing...@gmail.com wrote: I am trying to write a fn to correlate 2 signals using 3 nested map fn. I have 2 collections of data. THe first group of signals called target looks something like this. target: ( (1,2,3,4) (2,3,4,5) ...) The second collection is called signal and looks like this: signal: ( ((1,2,3,4)(2,3,4,5)(3,4,5,6)) ((2,3,4,5)(3,4,5,6)(4,5,6,7)) ... ) I would like to take the first list in target and multiply it by every list in the first group of signal. And then continue on processing the second list, etc... which would result in something like: ( ((1,4,9,16)(2,6,12,20)(3,8,15,24)) ((4,9,16,25) (6,12,20,30) (8,15,24,35)) ... ) I try a nested map fns like this, but can't get it to work: (map #(map #(map * %1 %2) %1 %2) target signal) -- BTW, I think using the (for ...) construct is cleaner and is a faithful translation of your intend. (map #(for [s %2] (map * %1 s)) target signal) Though personally I still think the %2 %1 is a bit confusing. -- 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
Re: trouble using nested map fn
On Mon, Aug 23, 2010 at 5:41 PM, Randy Hudson randy_hud...@mac.com wrote: Well, #(= lo % hi) is to my mind much more readable than (fn [x] (= lo x hi)), especially embedded in another form or two (as it would be). that may be true. though this IMO is partly due to the (=) construct's argument order. This is the case where it is a single argument function yet you need to explicitly spell that out as it is in the middle. -- 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
Re: trouble using nested map fn
There may be some value in the intellectual exercise to try something like your solution, but I think this is far more tractable if you use meaningful variable names: (map (fn [group scalars] (map (fn [trial] (map (fn [signal scalar] (* signal scalar)) trial scalars)) group)) signal target) You have one top-level list in 'target' for each top-level list in 'signal', so clearly the outer map must pair them. However, you want each 'target' sublist to be applied to several sublists, so you need the next map to iterate across the 2nd-level lists in 'signal'. Finally, the innermost map must do the actual work pairing each 'signal' and 'scalar'. Have all good days, David Sletten On Aug 23, 2010, at 11:26 AM, Glen Rubin wrote: I am trying to write a fn to correlate 2 signals using 3 nested map fn. I have 2 collections of data. THe first group of signals called target looks something like this. target: ( (1,2,3,4) (2,3,4,5) ...) The second collection is called signal and looks like this: signal: ( ((1,2,3,4)(2,3,4,5)(3,4,5,6)) ((2,3,4,5)(3,4,5,6)(4,5,6,7)) ... ) I would like to take the first list in target and multiply it by every list in the first group of signal. And then continue on processing the second list, etc... which would result in something like: ( ((1,4,9,16)(2,6,12,20)(3,8,15,24)) ((4,9,16,25) (6,12,20,30) (8,15,24,35)) ... ) I try a nested map fns like this, but can't get it to work: (map #(map #(map * %1 %2) %1 %2) target signal) -- 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 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
Re: trouble using nested map fn
Hi, On 24 Aug., 03:08, gary ng garyng2...@gmail.com wrote: (map #(for [s %2] (map * %1 s)) target signal) Though personally I still think the %2 %1 is a bit confusing.- Zitierten Text ausblenden - If you don't like it, don't use it.You can always give things meaningful names. (for [[signals target] (map vector signals-list target-list) signal signals] (map * signal target)) Sincerely Meikel -- 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
