not understand how to APPEND correctly to a sequential file

[jarychk]

This is a program as a continuation, after making it to show a member here how to open and display a sequential text file.

Now, I thought I would be able easily to extend the program to be able to append new information into the file, but it instead goes into the file wrong, and ruins the form of the file.

Whoever tries to check on this will find most of the trouble happens in the branch for subroutine, [anotherappend].


The file appearing and being now wrong (file been named ,  pianomencsv.txt :

 littlerich,macon,1932

fatsdom,new orleans,1928

jerry,ferriday,1935

proflonghair,bogalusa,1918

Dr. John,new orleans,1941ch. jack

new orleans

1910

The sample program:
 'csv simple example, to open and read csv file

'name this program boogiecsv.bas

'use the file pianomencsv.txt, 5 rows by 3 columns

'-----------------------------------------------

'file reading ability done.  now time to design APPEND ability

' call name of program, boogiecsv01.bas





'VARIABLES

dim who$(15,3)

name$=""         'name of player

bwhere$=""       'born where

byear$=""        'born what year

'i0=0            'loop variable

i1=0            'loop variable

rec=0           'record counter for how many persons



'OPEN THE FILE, LOAD THE ARRAY, CLOSE THE FILE

open "pianomencsv.txt" for input as #pno

   while eof(#pno)=0

   input #pno,name$

   input #pno,bwhere$

   input #pno,byear$

   rec=rec+1

   who$(rec,1)=name$

   who$(rec,2)=bwhere$

   who$(rec,3)=byear$

   wend

close #pno



'DISPLAY ARRAY RECORDS

gosub [showwhodata]



print

input "you wish to add another piano player? ";ans$

whans$=left$(ans$,1)

if whans$="y" or whans$="Y" then

gosub [anotherappend]

end if



'REINITIALIZE PROCESS VARIABLES

gosub [reinitialize]



END



[showwhodata]

print "We identified your ";rec;" piano players."

print

print "PIANO MAN","WHERE BORN","YEAR BORN"

for i0=1 to rec

   print who$(i0,1),who$(i0,2),who$(i0,3)

next i0

return



[reinitialize]

name$=""

bwhere$=""

byear$=""

rec=0

return



[anotherappend]

flagbadadd=0

input "piano player ";another$

input "born where, city ";whborn$

input "born in year ";whyear$

if another$="" or whborn$="" or whyear$="" then flagbadadd=1

if flagbadadd=0 then

   open "pianomencsv.txt" for append as #nu

   print #nu,another$

   print #nu,whborn$

   print #nu,whyear$

   close #nu

else

   'reset these variables and leave subroutine

   another$=""

   whborn$=""

   whyear$=""

   goto [leaveappend]

end if

[leaveappend]

return



[tsh73]

You program works only if data file has no newline after last line
(else check for EOF does not fire, and it starts to read next record, but there is none)

I think "right" approach is to read whole line and split it afterwards. This way you can see if line is empty and do (or don't do) something.

Now with things we had
we should keep adding new lines so it looks like previous lines (so we have to add ",")
and without last newline (add (;) after PRINT)
   open "pianomencsv.txt" for append as #nu
   'print #nu,another$
   'print #nu,whborn$
   'print #nu,whyear$
   print #nu, ""   'new line
   print #nu,another$;",";whborn$;",";whyear$;   'line delimited with ",", no new line
   close #nu


[jarychk]

tsh73, from your response of 7 hours ago, "...only if data file has no newline after last line"
I wonder if the results would have been successful if I had used the BAS program to be able to PRODUCE the sequential text file, instead of appending to an already created one using NOTEPAD.

I tried to send a response comment earlier but it seems to not have gone through.
I must study and review what you said, and think on it for a while...

[jarychk]

Instead of trying to completely understand the explanation from the post of very early today, I am finding that if the records file is created BY APPEND directly IN the .BAS program, then appending or adding further records to the sequential file works very well, and does not mishandle the file's expected formatting. I do not know why this works, but a nice find.

[tsh73]

But look at the file.
Does it looks like CSV?

[jarychk]

Jul 9, 2022 8:31:18 GMT tsh73 said:

But look at the file.
Does it looks like CSV?

Yes, it does look like that.  The file created as APPEND and then items added to it, take the form of rows of comma separated items; in the example I am using, this is each row is made of three items and each item is separated by a comma.  The program example I created for the study has not yet been given a code block to read the file for input, but I did open the file in NotePad to see how it looks there and it is the way I wanted.  

[tsh73]

Could you post your program,
or just saving part (if reading part same as posted)?
Others could benefit from your solution.

[jarychk]

Jul 9, 2022 10:18:38 GMT tsh73 said:

Could you post your program,
or just saving part (if reading part same as posted)?
Others could benefit from your solution.

This is a refeence file I used so I know what the information is for me, the user, to put in for building the file through the program (I removed one row of records intentionally, so this is showing five instead of six records::

paco de lucia,1947,2014

paco penya,1942,live

payohumberto,unreport,live

sabicas,1912,1990

Ninyo Ricardo,1904,1972

Again that is not the output file, but as a file which the program will produce, it CAN become the same as the programs output file.



Here is the still unfinished but in-progress program for study/relearn of how to handle sequential files:

' guitarists_file_study.bas    starting on july 8 2022

' name of file to make and use programmatically set to flamguitarists.txt

' this program is a APPEND , display, and file changes study; for study purposes use the ref_  file listings.





'VARIABLES

dim gtrts$(25,3)    'just want names, year born, year dead, but accepting other data kinds

name$=""

byear$=""

dyear$=""     'year died





   nomainwin



   WindowWidth = 592

   WindowHeight = 555



   UpperLeftX=int((DisplayWidth-WindowWidth)/2)

   UpperLeftY=int((DisplayHeight-WindowHeight)/2)



   button #main.button1, "build", [button1Click], UL, 14, 56, 122, 25

   button #main.button2, "view", [button2Click], UL, 158, 56, 122, 25

   button #main.button3, "make change", [button3Click], UL, 302, 56, 122, 25

   texteditor #main.texteditor4, 14, 121, 440, 325

   menu #main, "Edit"    '<--- Texteditor Menu can be moved but not removed.



   open "flamenco guitarists list" for window as #main

   print #main, "trapclose [quit.main]"



   print #main, "font ms_sans_serif 10"

   print #main.texteditor4, "!font Courier 10"



   wait



[quit.main]

   Close #main

   END





[button1Click]    'Perform action for the button named 'button1'

   'Insert your own code here



   nomainwin



   WindowWidth = 560

   WindowHeight = 355



   UpperLeftX=int((DisplayWidth-WindowWidth)/2)

   UpperLeftY=int((DisplayHeight-WindowHeight)/2)



   statictext #tofile.statictext1, "In order, give name, year born, year dead. button to add one at time", 22, 41, 488, 30

   statictext #tofile.statictext2, "unknown born? say unreported.  Not dead? say live.", 22, 76, 400, 20

   textbox #tofile.textbox3, 22, 126, 192, 30

   textbox #tofile.textbox4, 254, 126, 100, 25

   textbox #tofile.textbox5, 374, 126, 100, 25

   button #tofile.button6, "record to file", [button6Click], UL, 22, 271, 122, 25

   open "guitarists data to file" for window as #tofile

   print #tofile, "trapclose [quit.tofile]"



   print #tofile, "font ms_sans_serif 10"

   WAIT



   [button6Click]

   print #tofile.textbox3,"!contents? name$"

   print #tofile.textbox4,"!contents? byear$"

   print #tofile.textbox5,"!contents? dyear$"

   'APPEND the file

   open "flamguitarists.txt" for APPEND as #g

   print #g,name$;",";byear$;",";dyear$

   close #g

   'clear the text fields

   print #tofile.textbox3,"" : print #tofile.textbox4,"" : print #tofile.textbox5,""

   wait



   [quit.tofile]

   close #tofile

   wait





[button2Click]    'Perform action for the button named 'button2'

   'Insert your own code here

   wait





[button3Click]    'Perform action for the button named 'button3'

   'Insert your own code here

   wait








[tsh73]

Thanks for sharing

Others could benefit from your solution.

actually, first person happened to be me ;)

Really, I should apologise
Then I said

You program works only if data file has no newline after last line
(else check for EOF does not fire, and it starts to read next record, but there is none)

I thought I knew how it works.
Indeed I didn't.
(I could recall couple of similar occasions, so yes it happens with me).

It happens then you read last item in a file, it sets EOF regardless of last item has new line appended or not.

So my solution solved problem what likely did not exist.