How to invoke a function within a for loop in Lisp?

Question

I have 25 text files in my folder to be tested. But I don't want to write code for 25 files which means that it is 25 rows to test those files.

(myfunc "myfiles/txtfile1.txt")
(myfunc "myfiles/txtfile2.txt")
...

How can I use a for loop to invoke this function? Like the example code below. Sorry for my poor English

(loop for x from 1 to 25
  do ((myfunc "myfiles/txtfile~a.txt" x))
) 
)

` do ((myfunc "myfiles/txtfile~a.txt" x))` beware, the two following parenthesis are wrong. — Ehvince
– Ehvince, Commented May 7, 2020 at 9:58
Here's a primer on format directives: lispcookbook.github.io/cl-cookbook/… — Ehvince
– Ehvince, Commented May 7, 2020 at 9:59

Renzo · Accepted Answer · 2020-05-07 05:22:56Z

2

A simple way is to use the format function (manual):

(loop for x from 1 to 25
      do (myfunc (format nil "myfiles/txtfile~a.txt" x)))

Since all the files are in a directory, you could also give a look to the directory predefined function (manual, question in SO).

answered May 7, 2020 at 5:22

Renzo

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Hellseher · Accepted Answer · 2020-05-08 09:45:10Z

0

Some functional approach

(mapcar function (directory (merge-pathnames wildcard path)))

mapcar - applies function to the provided list of arguments generated by directory. function has to accept only one argument.

Working Example

61650326.lisp

;;;; File     : 61650326.lisp
;;;; Modified : <2020-5-08 Fri 08:51:12 BST>
;;;; URL      : https://stackoverflow.com/questions/61650326

(defparameter *user-path* "t/user/myfiles/")
(defparameter *wildcard* "*.txt")
(defparameter *function* 'type-of)

(defun map-on-files (path wildcard function)
    "Map FUNCTION on a list of files found under PATH WILDCARD."
    (mapcar function (directory (merge-pathnames wildcard path))))

(format t "~{~A~%~}" (map-on-files *user-path* *wildcard* *function*))

Generating some files for test purpose:

~$: mkdir -p t/user/myfiles
~$: for i in $(seq 10); do mktemp -p t/user/myfiles/ --suffix=.txt; done
t/user/myfiles/tmp.S4wKkJ85sq.txt
t/user/myfiles/tmp.j3XeT2hneq.txt
t/user/myfiles/tmp.mut6GLhlaT.txt
t/user/myfiles/tmp.1l0I5oGDaR.txt
t/user/myfiles/tmp.hBpvOfarye.txt
t/user/myfiles/tmp.m1WfmZxrU8.txt
t/user/myfiles/tmp.o6QbvjXMh9.txt
t/user/myfiles/tmp.6CmPvWf7GO.txt
t/user/myfiles/tmp.ZNWcaymY0g.txt
t/user/myfiles/tmp.JfUQ4cW0dD.txt

And Run code snippet

~$: sbcl --script 61650326.lisp
PATHNAME
PATHNAME
PATHNAME
PATHNAME
PATHNAME
PATHNAME
PATHNAME
PATHNAME
PATHNAME
PATHNAME

edited May 8, 2020 at 9:45

answered May 7, 2020 at 23:07

Hellseher

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3 Comments

Juan Rodre Over a year ago

Actually, that's exactly what I want to do but I am new on Lisp. My path is "user/myfiles/textfile.txt" can you give me an example from this path how I can read all files in this folder?

Hellseher Over a year ago

@JuanRodre I've extended answer with more explicit example

Juan Rodre Over a year ago

Thank you so much @Hellseher

Leo · Accepted Answer · 2020-05-07 05:20:36Z

0

You can concatenate the digit at the end of the filename with format:

(loop for x from 1 to 25 do (myfunc (format nil "myfiles/txtfile~a.txt" x)) )

answered May 7, 2020 at 5:20

Leo

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