CODEWITHSUNDEEP
iocommon-lisp
category
category

Reputation: 2165

write to end-of-line in file

I'm creating a function that adds a column to a flat file. So far I have:

(defun ff-from-vector (vec dir file)
  (with-open-file (ff-vec-str (make-pathname   :name file
                                               :directory dir)
                                               :direction :output
                                               :if-exists :overwrite)
    (dotimes (i (length vec))
      (format ff-vec-str "~A~%" (svref vec i)))))


(defun vec-from-1col-ff (dir file)
  (let ((col (make-array `(,(ff-rows dir file))))) 
        (with-open-file (ff-col-str (make-pathname  :name file
                                                    :directory dir)
                                                    :direction :input)
      (do ((line (read-line ff-col-str nil 'eof) 
                 (read-line ff-col-str nil 'eof))  
           (i 0 (incf i)))
           ((eql line 'eof))
           (setf (aref col i) (read-from-string line))))
  col))


(defun add-col-to-ff (col-dir col-file ff-dir ff-file)
  (ff-from-vector (vec-from-1col-ff col-dir col-file)   
                  ff-dir 
                  ff-file))

However, when I read from the file:

2 
2
2
2

And try to overwrite the file:

1 1 1 1
1 1 1 1
1 1 1 1
1 1 1 1

I get:

2 
2
2
2 
1 1 1 1
1 1 1 1
1 1 1 1
1 1 1 1

Essentially my question is: what function or code moves the formatting to the end of the line in the output file? So that I can get:

1 1 1 1 2
1 1 1 1 2
1 1 1 1 2
1 1 1 1 2

Upvotes: 0

Views: 71

Answers (1)

Rainer Joswig
Rainer Joswig

Reputation: 139321

You can't simply add more output to individual lines in a file without overwriting some data.

Create a new file and place the output there, taking the data from two input files.

Upvotes: 1

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