Search found 12 matches
- Thu May 03, 2012 4:47 pm
- Forum: Scheme
- Topic: write to a non existing file
- Replies: 1
- Views: 9057
write to a non existing file
I have written a version to write to an existing file: ;; write to an existing file (define write-to-a-file (lambda (path txt) (call-with-output-file path (lambda (output-port) (write txt output-port))))) I want to implement a version that checks if the file exists then the text is added to the file...
- Fri Nov 25, 2011 2:20 pm
- Forum: Common Lisp
- Topic: find list in a list function
- Replies: 6
- Views: 8343
Re: find list in a list function
Or if you prefer loops you could also use: (The proposed recursive version should be tail-recursive, but if you're unlucky with your compiler/interpreter it may blow the stack for very large lists) (defun sublist-p (list) (loop for el in list for sublist-p = (consp el) do (when sublist-p (return t)...
- Mon Nov 21, 2011 5:09 am
- Forum: Common Lisp
- Topic: find list in a list function
- Replies: 6
- Views: 8343
Re: find list in a list function
Ahh yes,thank you very much for your replies.I'll check and choose which version i prefer.
- Sun Nov 20, 2011 8:46 am
- Forum: Common Lisp
- Topic: find list in a list function
- Replies: 6
- Views: 8343
Re: find list in a list function
Ahhh thanks,your version works fine.But is there a way to achieve it without some?I'm asking for educational reasons.I'm asking from ansi common lisp book and so far "i've not being taught some" so there must be a way to do it without some.
Thanks for your help so far.
Thanks for your help so far.
- Sat Nov 19, 2011 3:56 pm
- Forum: Common Lisp
- Topic: find list in a list function
- Replies: 6
- Views: 8343
find list in a list function
Hello people,i'm trying to define a function that takes a list as an argument and returns true if one of its elements is a list. My function for some reason always returns nil. I'm using the listp predicate whichs returns true if something is a list but so far i fail to make it work as i want. (defu...
- Thu Nov 17, 2011 6:23 pm
- Forum: Scheme
- Topic: Questions In Matrix Multiplication
- Replies: 5
- Views: 18769
Re: Questions In Matrix Multiplication
First of all i'm really sorry for the late answer.But i study and write code in my free time and i have not much lately.
Secondly i want to thank you for the posted paradigms.Although it should be obvious,before your post it wasn't.
Once again thank you for your time.
Secondly i want to thank you for the posted paradigms.Although it should be obvious,before your post it wasn't.
Once again thank you for your time.
- Thu Nov 10, 2011 11:31 am
- Forum: Scheme
- Topic: Questions In Matrix Multiplication
- Replies: 5
- Views: 18769
Re: Questions In Matrix Multiplication
Ahhh wrong!!! It's not (map * row), it's (map * row column).
But is my substitution correct?
But is my substitution correct?
- Thu Nov 10, 2011 7:18 am
- Forum: Scheme
- Topic: Questions In Matrix Multiplication
- Replies: 5
- Views: 18769
Re: Questions In Matrix Multiplication
First of all thank you for your reply. :) Thank you for exaplaining the map procedure.So far i was not aware that the number of arguments of map depend on the procedure we map.(although i should :oops: ) Now this gives birth to a new question : The multiplication operator accepts any number of argum...
- Wed Nov 09, 2011 3:48 pm
- Forum: Scheme
- Topic: help writing a max procedure
- Replies: 4
- Views: 14512
Re: help writing a max procedure
I'm still a learner but shouldn't you use a parenthesis in (define ( my-max ... ( I mean before 'my-max'.) Also my second question might be silly but i'll ask anyway. I believe that you don't have both procedures in the same file.Right?Cause if you are not then there could be some name conflict ... ...
- Wed Nov 09, 2011 3:28 pm
- Forum: Scheme
- Topic: Questions In Matrix Multiplication
- Replies: 5
- Views: 18769
Questions In Matrix Multiplication
Hello there i have managed to multiply matrices with this(as shown at rosetta code): (define (matrix-multiply matrix1 matrix2) (map (lambda (row) (apply map (lambda column (apply + (map * row column))) matrix2)) matrix1)) where my map looks like this: ;;map: act to a list with a procedure ;;proc ---...