how to read specfic columns of data in a file.

This is a discussion on how to read specfic columns of data in a file. within the C Programming forums, part of the General Programming Boards category; Hi I wish to write code that allows me to access the specific column of 1, 2 and 4 respectively. ...

  1. #1
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    how to read specfic columns of data in a file.

    Hi I wish to write code that allows me to access the specific column of 1, 2 and 4 respectively. That is detector number, crystal number and theta columns in the data configuration file shown below.
    The configuration file I wish to access has data written in this format.

    CONFIGURATION FILE
    1st column: detector number
    2nd column: crystal number
    3rd column: ring
    4th column: theta
    5th column: phi
    6th column: include flag (0 to throw away)

    1 1 1 157.6 0 1
    2 2 1 157.6 72 1
    3 3 1 157.6 144 1
    4 4 1 157.6 216 1
    5 5 1 157.6 288 1
    6 6 2 133.5 18 1
    7 7 2 133.5 54 1
    8 8 2 133.5 90 1
    9 9 2 133.5 126 1
    10 10 2 133.5 162 1
    11 11 2 133.5 198 1
    12 12 2 133.5 234 1
    13 13 2 133.5 270 1
    14 14 2 133.5 306 1
    15 15 2 133.5 342 1
    16 16 1 109.0 19.5 1
    16 17 1 109.0 10.5 1
    16 18 2 100.0 10.5 1
    16 19 2 100.0 19.5 1
    17 20 1 109.0 49.5 1
    17 21 1 109.0 40.5 1
    17 22 2 100.0 40.5 1
    17 23 2 100.0 49.5 1
    18 24 1 109.0 79.5 1
    18 25 1 109.0 70.5 1
    18 26 2 100.0 70.5 1
    18 27 2 100.0 79.5 1
    19 28 1 109.0 109.5 1
    19 29 1 109.0 100.5 1
    19 30 2 100.0 100.5 1
    19 31 2 100.0 109.5 1
    20 32 1 109.0 139.5 1
    20 33 1 109.0 130.5 1
    20 34 2 100.0 130.5 1
    20 35 2 100.0 139.5 1
    21 36 1 109.0 169.5 1
    21 37 1 109.0 160.5 1
    21 38 2 100.0 160.5 1
    21 39 2 100.0 169.5 1
    22 40 1 109.0 199.5 1
    22 41 1 109.0 190.5 1
    22 42 2 100.0 190.5 1
    22 43 2 100.0 199.5 1
    23 44 1 109.0 229.5 1
    23 45 1 109.0 220.5 1
    23 46 2 100.0 220.5 1
    23 47 2 100.0 229.5 1
    24 48 0 0 0 0
    24 49 0 0 0 0
    24 50 0 0 0 0
    24 51 0 0 0 0
    25 52 1 109.0 289.5 1
    25 53 1 109.0 280.5 1
    25 54 2 100.0 280.5 1
    25 55 2 100.0 289.5 1
    26 56 1 109.0 319.5 1
    26 57 1 109.0 310.5 1
    26 58 2 100.0 310.5 1
    26 59 2 100.0 319.5 1
    27 60 1 109.0 349.5 1
    27 61 1 109.0 340.5 1
    27 62 2 100.0 340.5 1
    27 63 2 100.0 349.5 1
    28 64 4 71.0 10.5 1
    28 65 4 71.0 19.5 1
    28 66 3 80.0 19.5 1
    28 67 3 80.0 10.5 1
    29 68 4 71.0 40.5 1
    29 69 4 71.0 49.5 1
    29 70 3 80.0 49.5 1
    29 71 3 80.0 40.5 1
    30 72 4 71.0 70.5 1
    30 73 4 71.0 79.5 1
    30 74 3 80.0 79.5 1
    30 75 3 80.0 70.5 1
    31 76 4 71.0 100.5 1
    31 77 4 71.0 109.5 1
    31 78 3 80.0 109.5 1
    31 79 3 80.0 100.5 1
    32 80 4 71.0 130.5 1
    32 81 4 71.0 139.5 1
    32 82 3 80.0 139.5 1
    32 83 3 80.0 130.5 1
    33 84 4 71.0 160.5 1
    33 85 4 71.0 169.5 1
    33 86 3 80.0 169.5 1
    33 87 3 80.0 160.5 1
    34 88 4 71.0 190.5 1
    34 89 4 71.0 199.5 1
    34 90 3 80.0 199.5 1
    34 91 3 80.0 190.5 1
    35 92 4 71.0 220.5 1
    35 93 4 71.0 229.5 1
    35 94 3 80.0 229.5 1
    35 95 3 80.0 220.5 1
    36 96 4 71.0 250.5 1
    36 97 4 71.0 259.5 1
    36 98 3 80.0 259.5 1
    36 99 3 80.0 250.5 1
    37 100 4 71.0 280.5 1
    37 101 4 71.0 289.5 1
    37 102 3 80.0 289.5 1
    37 103 3 80.0 280.5 1
    38 104 4 71.0 310.5 1
    38 105 4 71.0 319.5 1
    38 106 3 80.0 319.5 1
    38 107 3 80.0 310.5 1
    39 108 4 71.0 340.5 1
    39 109 4 71.0 349.5 1
    39 110 3 80.0 349.5 1
    39 111 3 80.0 340.5 1

    So can anyone help me with how I can write code in my program to access this configuration file and read the data only in columns 1,2 and 4
    Any help would be appreciated.

  2. #2
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    Open file. fopen()
    Read line using fgets().
    Parse the line using sscanf().
    repeat until end of file.
    Close file. fclose()

    Post properly indented code in code tag if you have problem.
    Last edited by Bayint Naung; 06-12-2010 at 03:15 AM. Reason: ps

  3. #3
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    Imagine you had 4 int's in a row of data, and you only wanted the first and third int's:
    Code:
    int n1, n3, garbage;
    
    fscanf(myFilePointer, "%d %d %d %d", &n1, &garbage, &n3, &garbage);
    Using fgets and then using sscanf(), with this kind of idea, is a great way to go. sscanf() works a lot like fscanf(), of course.

  4. #4
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    You can just use assignment-suppression character *.
    Code:
       
          fscanf(fin,"%d %*d %d %*d",&n1,&n3);

  5. #5
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    Ok thanks everyone, I can read the data from the file. now I need to write code that connects the crystal numbers above 15 to the detector number since there are 4 crystals in each detector above detctor number 15..
    For example

    if there is an event (something is detected) in crystal 110 and 111 and I want to add these two events together how can I do that . I need to somehow assign crystal number 110 and 111 to detector 39.

    So that I can get any event which occurs in the same detcector and add them together.

    I started writing the code but became stuck. event fold by the way is just the number of events detected in a specified period of time.


    for(i=1;i<=event_fold;i++)

    if(event_fold >1 && detector[crystal_number[i]] > 15 )



    Any help would be appreciated.
    Last edited by zidangus; 06-16-2010 at 07:54 AM.

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