Random Write - Variable - Example Bug

[Mike Trader Member Find all posts View Profile Close Mike Trader]

The following code is in the manual and produces:
Joe 1 Joe 2 Joe 3

why dont I see the Integer Numbers?


#COMPILE EXE "Random.exe"

TYPE TestRec
uName AS STRING * 10
uNumber AS INTEGER
END TYPE

'¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤'
FUNCTION PBMAIN

DIM Rec AS TestRec, Record AS INTEGER

OPEN "RANDOM.DTA" FOR RANDOM AS #1 LEN = LEN(TestRec)

FOR Record = 1 TO 3
Rec.uName = "Joe" + STR$(Record)
Rec.uNumber = Record
PUT #1,Record, Rec
NEXT Record

CLOSE #1


END FUNCTION
'------------------------------------------------------------------------------

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Kind Regards
Mike

[Paul Squires Member Find all posts View Profile Close Paul Squires]

I just ran the example and looked at the resulting "random.dta"
file and I could see Joe 1, Joe 2 and Joe 3 in the file. There
must be something else coming into play on your end????

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Paul Squires
mailto:[email protected][email protected]</A>

[This message has been edited by Paul Squires (edited March 04, 2001).]

[Don Dickinson Member Find all posts View Profile Close Don Dickinson]

What are you expecting to see? Integers are stored in 2-byte binary represenation. The number one is actually stored as chr$(0) + chr$(1) (did i get that right? i always get my endians mixed up )
When you open the random file in a text editor you won't see a 1, you'll see a ch$(0) + chr$(1) - these are not human readable via a text editor (a hex-editor, yes, but not a text editor).
Best Regards,
Don


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www.basicguru.com/dickinson

[Mike Trader Member Find all posts View Profile Close Mike Trader]

Yes I get Joe1 Joe2 and Joe3
BUT those are the strings. The VARIABLE should also be after each "Joe" all I get is three " "

FYI I am writing an app that converts 10k lines of data. It creates a new file in the process. After the file is created I want to go back in and insert the total number of lines in the file on the first line for the next EXE to read

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Kind Regards
Mike

[Borje Hagsten Member Find all posts View Profile Close Borje Hagsten]

Add the following to your code, after file is closed after writing,
and see that it works.

OPEN "RANDOM.DTA" FOR RANDOM AS #1 LEN = LEN(TestRec)
  GET #1, 3, Rec 'Get third record
  MSGBOX Rec.uName & STR$(Rec.uNumber)
  GET #1, 2, Rec 'Get second record 
  MSGBOX Rec.uName & STR$(Rec.uNumber)
CLOSE #1

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[Mike Trader Member Find all posts View Profile Close Mike Trader]

Don,

It doesnt say that Variables are stored in Binary format in the manual, but to answer your question I was hoping to see:
1 2 3
I am creating an ascii file. Every other line is Ascii format.

So i guess the question becomes, how do I PUT a variable in ascii format, (just like all the variables written to the file with
WRITE# )

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Kind Regards
Mike

[Mike Trader Member Find all posts View Profile Close Mike Trader]

Borje,
Yes that worx - thx, but the Ascii File Random.dta must be readable in ascii format for another EXE.

I need to find a way to overwrite the first record with an ascii number. Is the only way to do this with the number converted to a string?

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Kind Regards
Mike

[Borje Hagsten Member Find all posts View Profile Close Borje Hagsten]

If you want to put a variable in ASCII format, change the declared
type to something like:

TYPE TestRec
  uName   AS STRING * 10
  uNumber AS STRING * 10
END TYPE

..and convert the variable to string format before you PUT it into the
record. Better to use the way you do, though, and convert to string
after GET command, using FORMAT$(Rec.uNumber). STR$(), used in my
sample adds a leading space, so better to use FORMAT$ for other use than
showing in MSGBOX..


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[Mike Trader Member Find all posts View Profile Close Mike Trader]

OK thx but I tried that. There is a problem - it overwrites my data!

Here is a much better example of what i am trying to do. The problem is evident in the .dta file

#COMPILE EXE "Random.exe"

GLOBAL Line1Str AS STRING * 10
GLOBAL Record AS LONG, Count AS LONG
GLOBAL SomeVar1 AS LONG, SomeVar2 AS LONG
'¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤'
FUNCTION PBMAIN

OPEN "RANDOM.DTA" FOR OUTPUT AS #1
FOR Record=3001 TO 3014
SomeVar1 = VAL(DATE$)
SomeVar2 = VAL(TIME$)
WRITE #1, Record-3000, 0, 0, 0, SomeVar1, 0, 0, SomeVar2, Record
INCR Count
NEXT
CLOSE #1

'--------------- write the number of lines on Line 1

OPEN "RANDOM.DTA" FOR RANDOM AS #1 LEN = LEN(Line1Str)
Line1Str = LTRIM$(STR$(Count))
PUT #1, 1, Line1Str
CLOSE #1

END FUNCTION
'¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤'

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Kind Regards
Mike

[Borje Hagsten Member Find all posts View Profile Close Borje Hagsten]

Look up the SEEK command. You can place a header at the beginning
of a file, like a full structure or a variable, using PUT/GET, then
use SEEK to set position to proper place and WRITE/INPUT whatever
you need.

If header is just one LONG, PUT/GET it at beginning of file, then
use, SEEK #1, 4 to set position for further WRITE/PRINT/INPUT..

Correction: Should be SEEK #1, 5, unless you have you used BASE = 0
on the OPEN line (according to PB's helpfile).
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[This message has been edited by Borje Hagsten (edited March 04, 2001).]

[Mike Trader Member Find all posts View Profile Close Mike Trader]

Sorry Borje, that went right over my head. Can you use my example to show me pls

Actually, I have 3 or 4 variables to write on the first line. the first of which is the total number of lines in the file.

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Kind Regards
Mike

[Bern Ertl Member Find all posts View Profile Close Bern Ertl]

Mike, perhaps it would be easier to create a second file to
contain statistics / pointers for the first file?



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Bernard Ertl

[Mike Trader Member Find all posts View Profile Close Mike Trader]

No can do Bern. First Line has to contain all the pertinant info about the file and the data in the file. Thats the format im trying to emulate.

Of course I could just copy the first file to a second file and write the first line correctly as I do it, but for 10k+ lines that seems kinda lame.

It must be possible to write randomly to a file without being constrained to Binary data surely?

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Kind Regards
Mike

[Borje Hagsten Member Find all posts View Profile Close Borje Hagsten]

Okay, so a bit more complicated, if each line must be separate string
and first line hold file data in form of a string. Forget SEEK. Here's
a way of doing it - involves reading entire file into an array:

LOCAL I AS LONG, J AS LONG, hString AS STRING, tmp AS STRING, Rec() AS TestRec
 
'Create first instance of test file
OPEN "RANDOM.DTA" FOR OUTPUT AS #1
  PRINT #1, FORMAT$(I) 'empty line, for file data
  FOR I = 1 TO 3
    PRINT #1, "Joe" + STR$(I)
    PRINT #1, FORMAT$(I)
  NEXT
CLOSE #1
 
'Read test file into array
I = 0
OPEN "RANDOM.DTA" FOR INPUT AS #1
  IF LOF(1) THEN LINE INPUT #1, hString 'read file data separately
  DO WHILE NOT EOF(1)
     IF I MOD 20 = 0 THEN REDIM PRESERVE Rec(I + 20)
     LINE INPUT #1, Rec(I).uName
     LINE INPUT #1, tmp
     Rec(I).uNumber = VAL(tmp)
     INCR I
  LOOP
  DECR I
  REDIM PRESERVE Rec(I)
CLOSE #1
MSGBOX hString & $CRLF & Rec(0).uName & STR$(Rec(0).uNumber)
 
'Write all back, including first line data
OPEN "RANDOM.DTA" FOR OUTPUT AS #1
  PRINT #1, FORMAT$(I) 'print file data separately
  FOR J = 0 TO I
    PRINT #1, Rec(J).uName
    PRINT #1, FORMAT$(Rec(J).uNumber)
  NEXT
CLOSE #1
 
'Check to see that it worked
I = 0
OPEN "RANDOM.DTA" FOR INPUT AS #1
  IF LOF(1) THEN LINE INPUT #1, hString
  DO WHILE NOT EOF(1)
     IF I MOD 20 = 0 THEN REDIM PRESERVE Rec(I + 20)
     LINE INPUT #1, Rec(I).uName
     LINE INPUT #1, tmp
     Rec(I).uNumber = VAL(tmp)
     INCR I
  LOOP
  REDIM PRESERVE Rec(I - 1)
CLOSE #1
MSGBOX hString & $CRLF & Rec(0).uName & STR$(Rec(0).uNumber)

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[This message has been edited by Borje Hagsten (edited March 04, 2001).]

[Mike Trader Member Find all posts View Profile Close Mike Trader]

Borje,
Thanks so much for that example. That will work but it seems crazy to have to read the whole file into memory just to write the first line.

I might as well just read each line of the file and write it to a new file. That way I can write the first line with all the data needed.

Also If I use a file with 1min data, thats 405 lines per day, 5 days per week, 52 weeks per year = 105300. I need to go back at least 4 years so thats 421000 lines.

I would much rather find a way to over write the first line!

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Kind Regards
Mike

[Lance Edmonds Member Find all posts View Profile Close Lance Edmonds]

Personally, I'd "reserve" a fixed number of bytes at the beginning of the file, using some muliple of the actual data record size.

Then you can write to that portion of the file with BINARY mode, and reopen the file in RANDOM mode and read the records.

For example, if your record is 32 bytes, reserve the 1st two records for the "ascii" data, and start your real records at byte 65 (record 3). You could also read/write the records in binary mode too - what ever is easier for you. The following technique will enable the first 24 bytes to be read with LINE INPUT if required.

' pseudocode:
TYPE TestRec
  uName AS STRING * 10
  uNumber AS INTEGER
END TYPE
 
TYPE HeaderRec
  Header AS STRING * 22 ' (10 + 2) * 2 - 2
  Terminator AS STRING * 2
END TYPE
  
Dim Rec AS TestRec
Dim Header As HeaderRec
 
Header.Header = "Record Count = " + FORMAT$(RecCount&)
Header.Terminator = $CRLF
 
OPEN file$ FOR BINARY AS #1
 PUT$ #1,, Header
CLOSE #1

OPEN file$ FOR RANDOM AS #1
 FOR x& = 3 to (LOF(1) - LEN(Header)) \ LEN(Rec)
  GET #1, x&, Rec
  '... process Rec
 NEXT x&
CLOSE #1
 
' Now read the first two records as you would a sequential file.
OPEN file$ FOR INPUT AS #1
 LINE INPUT #1, a$
 MSGBOX a$
CLOSE

Anyway, I hope you get the idea.


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Lance
PowerBASIC Support
mailto:[email protected][email protected]</A>

[Borje Hagsten Member Find all posts View Profile Close Borje Hagsten]

There many ways to do this. Problem is you need the file to be like
ordinary text file, if I have understood this correctly. If each
record (line) has same length, the following may give you an idea
of a better way:

#COMPILE EXE "Random.exe"
 
TYPE TestRec
  uName   AS STRING * 10
  uNumber AS STRING * 10
END TYPE
 
'¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤'
FUNCTION PBMAIN
LOCAL I AS LONG, hString AS STRING, Rec AS TestRec
 
'Create test file
OPEN "RANDOM.DTA" FOR OUTPUT AS #1
  PRINT #1, SPACE$(10)
  FOR I = 1 TO 3
     Rec.uName = "Joe" + STR$(I)
     Rec.uNumber = FORMAT$(I)
    PRINT #1, Rec.uName
    PRINT #1, Rec.uNumber
  NEXT
CLOSE #1
 
'Test to see whole file
OPEN "RANDOM.DTA" FOR BINARY AS #1
   hString = SPACE$(LOF(1))
   GET #1,, hString
CLOSE #1
MSGBOX hString
 
'Change header
OPEN "RANDOM.DTA" FOR BINARY AS #1 BASE = 0
   hString = FORMAT$(I - 1)     '<- Change header
   PUT #1,, hString
 
   I = 1
   Rec.uName = "Borje" + STR$(I)
   SEEK #1, I * 12               '<- set position to first record
   PUT #1,, Rec.uName            '<- put changed data
CLOSE #1
 
'Test to see whole file
OPEN "RANDOM.DTA" FOR BINARY AS #1
   hString = SPACE$(LOF(1))
   GET #1,, hString
CLOSE #1
MSGBOX hString
 
END FUNCTION

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[Mike Trader Member Find all posts View Profile Close Mike Trader]

Thx Lance, But I have to adhere to the file format im trying to emulate ie all Ascii charaters/Numbers

Borje,
Thx for that example. I have examined it carefully. I am trying to avoing reading 100k lines into memory tho.

I think I must simply create another file and reall all the lines one by one in and write them to the new file.

It is becoming obvious that RANDOM was designed for Binary read/Write and not Ascii data like the INPUT# and WRITE# cousins.

Thx again

------------------
Kind Regards
Mike

[Michael Mattias Member Find all posts View Profile Close Michael Mattias]

It is becoming obvious that RANDOM was designed for Binary read/Write and not Ascii data like the INPUT# and WRITE# cousins.

No, that's not correct. The *type* of data - printable or unprintable - has nothing to do with the *access mode* used (except as below).

INPUT# and WRITE#/PRINT# were designed for *sequential* access.

PUT/GET/SEEK were designed for random (small letters) access.

The only place data "type" makes a difference is in the INPUT# or LINE INPUT# verbs, where the verb means, "read from the current file pointer forwar up to the next comma/CRLF/EOF and advance the pointer beyond the delimiter." Consequently, you cannot use these verbs with data which may be *interpreted* as one of the delimiter characters.

The so-called "binary" representation of the the integer value 13 would be interpreted as CHR$(13) + CHR$(0) , or carriage return, nul; so LINE INPUT$ should not be used to get the value of 16-bit integers expressed in native ("binary") format.

MCM

[Borje Hagsten Member Find all posts View Profile Close Borje Hagsten]

I don't understand. If you use my last sample, you can change any
record with the help of SEEK and PUT. No need to read whole file
into memory, even though 100KB isn't much today..


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