Error in reading data file QB64

PeterTX · Apr 24, 2022

Dear Qbasic friends,
I am new to this group, I just use the qbasic for my research calculation because it is very easy to write the codes. Now I need your help with data file reading. I downloaded a data file which contains only numbers separated with TAB not the space, each line has 10 numbers, the first line likes 1 2 3 4 5 6 7 8 9 10, the second line likes 11 12 13 14 15 16 17 18 19 20, ......
the input statement is INPUT #1, a(1), a(2), a(3), a(4), a(5), a(6), a(7), a(8), a(9), a(10). However, it only reads the first number from each line, i.e, it only read 1 and 11....

I tested a data file with numbers separated by space created by Notepad, it works well, it will not work if the numbers are separated by tabs.

I cannot change the original data file. So please help me to solve the problem, maybe an easy fix.
I really appreciate your help.

Peter

mikrom · Apr 25, 2022

Hi PeterTX,
I tried to read the file line by line and parse numbers from every line by locating the TAB-characters and the numbers, i used INSTR and MID$ functions for this..

Here is the example, which you can try:
text_file.bas

Code:

[COLOR=#0000ff]'writing and reading text file[/color]
[COLOR=#804040][b]Const[/b][/color] N = [COLOR=#ff00ff]8[/color]
[COLOR=#804040][b]Dim[/b][/color] A(N - [COLOR=#ff00ff]1[/color], N - [COLOR=#ff00ff]1[/color])
[COLOR=#804040][b]Dim[/b][/color] B(N - [COLOR=#ff00ff]1[/color], N - [COLOR=#ff00ff]1[/color])
data_file[COLOR=#2e8b57][b]$[/b][/color] = [COLOR=#ff00ff]"my_data.txt"[/color]
quote_char[COLOR=#2e8b57][b]$[/b][/color] = Chr[COLOR=#2e8b57][b]$[/b][/color]([COLOR=#ff00ff]34[/color])
tab_char[COLOR=#2e8b57][b]$[/b][/color] = Chr[COLOR=#2e8b57][b]$[/b][/color]([COLOR=#ff00ff]9[/color])


[COLOR=#0000ff]'populate matrix A with random data and print it[/color]
[COLOR=#804040][b]Print[/b][/color] [COLOR=#ff00ff]"matrix A:"[/color]
[COLOR=#804040][b]For[/b][/color] i = [COLOR=#ff00ff]0[/color] To N - [COLOR=#ff00ff]1[/color]
    [COLOR=#804040][b]For[/b][/color] j = [COLOR=#ff00ff]0[/color] To N - [COLOR=#ff00ff]1[/color]
        [COLOR=#804040][b]Randomize[/b][/color] [COLOR=#804040][b]Timer[/b][/color]
        A(i, j) = [COLOR=#008080]Int[/color]([COLOR=#008080]Rnd[/color] * [COLOR=#ff00ff]100[/color])
        [COLOR=#804040][b]Print[/b][/color] [COLOR=#804040][b]Using[/b][/color] [COLOR=#ff00ff]"  ##"[/color]; A(i, j);
    [COLOR=#804040][b]Next[/b][/color] j
    [COLOR=#804040][b]Print[/b][/color] '[COLOR=#804040][b]next[/b][/color] [COLOR=#804040][b]line[/b][/color]
[COLOR=#804040][b]Next[/b][/color] i
[COLOR=#804040][b]Print[/b][/color]


[COLOR=#804040][b]Print[/b][/color] [COLOR=#ff00ff]"Writing matrix A to the file "[/color] _
      + quote_char[COLOR=#2e8b57][b]$[/b][/color] + data_file[COLOR=#2e8b57][b]$[/b][/color] + quote_char[COLOR=#2e8b57][b]$[/b][/color]
[COLOR=#804040][b]Print[/b][/color]
[COLOR=#0000ff]'write matrix A into the file[/color]
[COLOR=#0000ff]'numbers are separated by tab-characters[/color]
[COLOR=#804040][b]Open[/b][/color] data_file[COLOR=#2e8b57][b]$[/b][/color] [COLOR=#804040][b]For[/b][/color] Output As [COLOR=#2e8b57][b]#1[/b][/color]
[COLOR=#804040][b]For[/b][/color] i = [COLOR=#ff00ff]0[/color] To N - [COLOR=#ff00ff]1[/color]
    output_line[COLOR=#2e8b57][b]$[/b][/color] = [COLOR=#ff00ff]""[/color]
    [COLOR=#804040][b]For[/b][/color] j = [COLOR=#ff00ff]0[/color] To N - [COLOR=#ff00ff]1[/color]
        A_i_j[COLOR=#2e8b57][b]$[/b][/color] = LTrim[COLOR=#2e8b57][b]$[/b][/color](Str[COLOR=#2e8b57][b]$[/b][/color](A(i, j)))
        [COLOR=#804040][b]If[/b][/color] j < N - [COLOR=#ff00ff]1[/color] [COLOR=#804040][b]Then[/b][/color]
            output_line[COLOR=#2e8b57][b]$[/b][/color] = output_line[COLOR=#2e8b57][b]$[/b][/color] + A_i_j[COLOR=#2e8b57][b]$[/b][/color] + tab_char[COLOR=#2e8b57][b]$[/b][/color]
        [COLOR=#804040][b]Else[/b][/color]
            output_line[COLOR=#2e8b57][b]$[/b][/color] = output_line[COLOR=#2e8b57][b]$[/b][/color] + A_i_j[COLOR=#2e8b57][b]$[/b][/color]
        [COLOR=#804040][b]End[/b][/color] [COLOR=#804040][b]If[/b][/color]
    [COLOR=#804040][b]Next[/b][/color] j
    [COLOR=#804040][b]Print[/b][/color] [COLOR=#2e8b57][b]#1[/b][/color], output_line[COLOR=#2e8b57][b]$[/b][/color]
[COLOR=#804040][b]Next[/b][/color] i
[COLOR=#804040][b]Close[/b][/color] [COLOR=#2e8b57][b]#1[/b][/color]


[COLOR=#804040][b]Print[/b][/color] [COLOR=#ff00ff]"Reading data from the file "[/color] _
      + quote_char[COLOR=#2e8b57][b]$[/b][/color] + data_file[COLOR=#2e8b57][b]$[/b][/color] + quote_char[COLOR=#2e8b57][b]$[/b][/color] _
      [COLOR=#ff00ff]" into matrix B"[/color]
[COLOR=#804040][b]Print[/b][/color]
[COLOR=#804040][b]Open[/b][/color] data_file[COLOR=#2e8b57][b]$[/b][/color] [COLOR=#804040][b]For[/b][/color] [COLOR=#804040][b]Input[/b][/color] As [COLOR=#2e8b57][b]#1[/b][/color]
i = [COLOR=#ff00ff]0[/color]
[COLOR=#804040][b]Do[/b][/color] [COLOR=#804040][b]While[/b][/color] Not [COLOR=#008080]EOF[/color]([COLOR=#ff00ff]1[/color])
[COLOR=#0000ff]    'input_line has the structure:[/color]
[COLOR=#0000ff]    'NUM TAB NUM TAB .. TAB NUM CR LF[/color]
    [COLOR=#804040][b]Input[/b][/color] [COLOR=#2e8b57][b]#1[/b][/color], input_line[COLOR=#2e8b57][b]$[/b][/color]
[COLOR=#0000ff]    'parse numbers from the input_line string[/color]
[COLOR=#0000ff]    'and store them into the matrix B[/color]
    start = [COLOR=#ff00ff]1[/color]
    [COLOR=#804040][b]For[/b][/color] j = [COLOR=#ff00ff]0[/color] To N - [COLOR=#ff00ff]1[/color]
        tab_idx = InStr(start, input_line[COLOR=#2e8b57][b]$[/b][/color], tab_char[COLOR=#2e8b57][b]$[/b][/color])
        [COLOR=#804040][b]If[/b][/color] tab_idx [COLOR=#804040][b]Then[/b][/color]
            B(i, j) = [COLOR=#008080]Val[/color](Mid[COLOR=#2e8b57][b]$[/b][/color](input_line[COLOR=#2e8b57][b]$[/b][/color], start, tab_idx - start + [COLOR=#ff00ff]1[/color]))
            start = tab_idx + [COLOR=#008080]Len[/color](tab_char[COLOR=#2e8b57][b]$[/b][/color])
        [COLOR=#804040][b]Else[/b][/color]
            line_len = [COLOR=#008080]Len[/color](input_line[COLOR=#2e8b57][b]$[/b][/color])
            B(i, j) = [COLOR=#008080]Val[/color](Mid[COLOR=#2e8b57][b]$[/b][/color](input_line[COLOR=#2e8b57][b]$[/b][/color], start, line_len - start + [COLOR=#ff00ff]1[/color]))
        [COLOR=#804040][b]End[/b][/color] [COLOR=#804040][b]If[/b][/color]
    [COLOR=#804040][b]Next[/b][/color]
    i = i + [COLOR=#ff00ff]1[/color]
[COLOR=#804040][b]Loop[/b][/color]
[COLOR=#804040][b]Close[/b][/color] [COLOR=#2e8b57][b]#1[/b][/color]


[COLOR=#0000ff]'print matrix B[/color]
[COLOR=#804040][b]Print[/b][/color] [COLOR=#ff00ff]"matrix B:"[/color]
[COLOR=#804040][b]For[/b][/color] i = [COLOR=#ff00ff]0[/color] To N - [COLOR=#ff00ff]1[/color]
    [COLOR=#804040][b]For[/b][/color] j = [COLOR=#ff00ff]0[/color] To N - [COLOR=#ff00ff]1[/color]
        [COLOR=#804040][b]Print[/b][/color] [COLOR=#804040][b]Using[/b][/color] [COLOR=#ff00ff]"  ##"[/color]; B(i, j);
    [COLOR=#804040][b]Next[/b][/color] j
    [COLOR=#804040][b]Print[/b][/color] '[COLOR=#804040][b]next[/b][/color] [COLOR=#804040][b]line[/b][/color]
[COLOR=#804040][b]Next[/b][/color] i

The program first creates the matrix A of random numbers and prints it.
Then it writes the matrix A into text file with the structure:
[tt]NUM TAB NUM TAB .. TAB NUM CR LF[/tt]
like this:
my_data.txt

Code:

4	95	73	13	94	77	3	23
90	89	65	38	91	34	58	85
50	83	56	64	14	91	86	74
10	4	48	90	37	48	41	63
69	98	39	42	60	79	69	26
56	92	31	68	57	36	97	15
16	12	22	93	80	94	52	77
75	6	14	19	3	51	80	66

At end it reads the data from the file into matrix B and prints it.

mikrom · Apr 25, 2022

Hi PeterTX,

Is it working for you ?

PeterTX · Apr 25, 2022

Dear Mikrom,
Thank you for your great help. It really solved the problem.

Peter

mikrom · Apr 25, 2022

PeterTX,
you are welcome

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Error in reading data file QB64

PeterTX

Technical User

mikrom

Programmer

mikrom

Programmer

PeterTX

Technical User

mikrom

Programmer

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