Get variable value from imported text

Hello, I want to make database from the data inside my files

Here is the example of the data inside the file:

let's say I want to import the years, month, day (2020 10 3) in the first row of the data using importdata function to a matrix structure. The imported matrix is 10x1 cell in which 1 cell contains the string in 1 row. How to take just 2020 in first row string and store it in years, 10 in month, etc in the structure?

And another question, there is a table in the bottom of the data, at the example the header is in line 7. The header may be different for each file data, it may be in line 8 or 9. Is there any way to detect the header and import the data below it as a matrix structure?

edit here is attached the input data and the output example that I want

Here is the code that I tried to build:

St=struct('years',0.0,'month',0.0,'day',0.0, ...
    'hours',0.0,'min',0.0,'sec',0.0);

files=dir('*-*'); 
N=length(files);

for i=1:N
    file=files(i).name;
    S=importdata(file);
    St.years=S{1,1};
    St.month=S{1,1};
    St.day=S{1,1};
end

[dpb]

Attach data file or at least a text file or code section of data, not images. Nothing can be done with them

[Image Analyst]

No idea without the data. What do you want and want do you not want (want to ignore)? Anonymize it with generic data if you think it's too secret to post. Otherwise probably no one can help.

[theo]

I'm really sorry, here is the example of the input data and the output data that I want

Answer 1

[Seth Furman]

Sounds like you could use readtable.

https://www.mathworks.com/help/matlab/ref/readtable.html

>> readtable('05-2350-33R.S202010','NumHeaderLines',7,'FileType','text','VariableNamingRule','preserve')

ans =

  3×15 table

     STAT        SP      IPHASW     D     HRMM    SECON    CODA    AMPLIT    PERI    AZIMU    VELO    AIN    AR TRES W    DIS     CAZ7
    _______    ______    ______    ___    ____    _____    ____    ______    ____    _____    ____    ___    _________    ____    ____

    {'JBS'}    {'KZ'}    {'IP'}    NaN    2351    23.45     42      NaN      NaN      NaN     NaN     33      -0.0001     2596    153 
    {'MTK'}    {'KZ'}    {'IP'}    NaN    2351    25.93     60      NaN      NaN      NaN     NaN     29       0.0001     2623    154 
    {'SLT'}    {'KZ'}    {'IP'}    NaN    2351    28.15     57      NaN      NaN      NaN     NaN     28      -0.0001     2650    152 

Normally readtable tries to detect and ignore any header lines, but it looks like readtable has trouble doing this with your files, so you'll probably have to explicitly specify the number of header lines (see 'NumHeaderLines' above).

Consider readcell or textscan if you want to read non-tabular data, e.g. the data in the header lines.

https://www.mathworks.com/help/matlab/ref/readcell.html

https://www.mathworks.com/help/matlab/ref/textscan.html

[theo]

thank you for your help, i've tried it and works :D

but there are still some issues

1. is there any other way to specify the header line other than defining the line number? ie using "STAT" as the sign for the beginning of header
2. how to define the type of imported data, ie I want to specify that 23.45 is integer. Or it is automatically defined?

[dpb]

1. Not automagically, no, 'NumHeaderLines' is only a numeric integer input; there isn't an option to set a 'Lookfor' string
2. 23.45 is not an integer; declaring it to be such will cause either a failure of a mismatched datatype or, at best, bringing the column/variable in as a cellstr instead of numeric. I didn't run a test to confirm exact behavior. If you want to round those to integral values, you'll have to do that after reading them into the table. NB: that by default, all numeric variables in MATLAB are double, anyway.

[Seth Furman]

1) How to specify the number of header lines if not known in advance?

Assuming you know that the line with table variable names is the first line that starts with 'STAT', for instance, you can calculate the number of header lines by reading the file line-by-line, finding the index of the first line that starts with 'STAT', and subtracting one from that number to get the number of header lines. For instance, you can use readlines to read the file as separate lines and then use startsWith and find to get the first line starting with 'STAT'.

https://www.mathworks.com/help/matlab/ref/readlines.html

https://www.mathworks.com/help/matlab/ref/startswith.html

https://www.mathworks.com/help/matlab/ref/find.html

>> lines = readlines('05-2350-33R.S202010','WhitespaceRule','trim');
>> startsWithStat = startsWith(lines,'STAT');
>> indexFirstStat = find(startsWithStat,1)

indexFirstStat =

     8

>> numHeaderLines = indexFirstStat - 1

numHeaderLines =

     7

>> t = readtable('05-2350-33R.S202010','NumHeaderLines',numHeaderLines,'FileType','text','VariableNamingRule','preserve')

t =

  3×15 table

     STAT        SP      IPHASW     D     HRMM    SECON    CODA    AMPLIT    PERI    AZIMU    VELO    AIN    AR TRES W    DIS     CAZ7
    _______    ______    ______    ___    ____    _____    ____    ______    ____    _____    ____    ___    _________    ____    ____

    {'JBS'}    {'KZ'}    {'IP'}    NaN    2351    23.45     42      NaN      NaN      NaN     NaN     33      -0.0001     2596    153 
    {'MTK'}    {'KZ'}    {'IP'}    NaN    2351    25.93     60      NaN      NaN      NaN     NaN     29       0.0001     2623    154 
    {'SLT'}    {'KZ'}    {'IP'}    NaN    2351    28.15     57      NaN      NaN      NaN     NaN     28      -0.0001     2650    152 

2) How to specify imported data types?

One method is to modify the imported values, e.g. using one of the integer conversion functions.

https://www.mathworks.com/help/matlab/ref/int64.html

>> t.SECON = int64(t.SECON)

t =

  3×15 table

     STAT        SP      IPHASW     D     HRMM    SECON    CODA    AMPLIT    PERI    AZIMU    VELO    AIN    AR TRES W    DIS     CAZ7
    _______    ______    ______    ___    ____    _____    ____    ______    ____    _____    ____    ___    _________    ____    ____

    {'JBS'}    {'KZ'}    {'IP'}    NaN    2351     23       42      NaN      NaN      NaN     NaN     33      -0.0001     2596    153 
    {'MTK'}    {'KZ'}    {'IP'}    NaN    2351     26       60      NaN      NaN      NaN     NaN     29       0.0001     2623    154 
    {'SLT'}    {'KZ'}    {'IP'}    NaN    2351     28       57      NaN      NaN      NaN     NaN     28      -0.0001     2650    152     

Another method is to specify import types using import options.

https://www.mathworks.com/help/matlab/ref/detectimportoptions.html

>> opts = detectImportOptions('05-2350-33R.S202010','FileType','text','NumHeaderLines',numHeaderLines,'VariableNamingRule','preserve')

opts = 

  FixedWidthImportOptions with properties:

   Format Properties:
                  Whitespace: '\b\t '
                  LineEnding: {'\n'  '\r'  '\r\n'}
                CommentStyle: {}
               EmptyLineRule: 'skip'
                    Encoding: 'UTF-8'

   Replacement Properties:
                 MissingRule: 'fill'
             ImportErrorRule: 'fill'
            ExtraColumnsRule: 'addvars'
            PartialFieldRule: 'keep'

   Variable Import Properties: Set types by name using setvartype
               VariableNames: {'STAT', 'SP', 'IPHASW' ... and 12 more}
               VariableTypes: {'char', 'char', 'char' ... and 12 more}
              VariableWidths: [5 3 7 2 5 6 5 7 5 6 5 4 10 5 5]
       SelectedVariableNames: {'STAT', 'SP', 'IPHASW' ... and 12 more}
             VariableOptions: Show all 15 VariableOptions 
	Access VariableOptions sub-properties using setvaropts/getvaropts
          VariableNamingRule: 'preserve'

   Location Properties:
                   DataLines: [9 Inf]
           VariableNamesLine: 8
              RowNamesColumn: 0
           VariableUnitsLine: 0
    VariableDescriptionsLine: 0 
	To display a preview of the table, use preview

>> opts.VariableTypes{6} = 'int64';
>> t = readtable('05-2350-33R.S202010',opts)

t =

  3×15 table

     STAT        SP      IPHASW        D         HRMM    SECON    CODA      AMPLIT         PERI         AZIMU          VELO       AIN    AR TRES W    DIS     CAZ7
    _______    ______    ______    __________    ____    _____    ____    __________    __________    __________    __________    ___    _________    ____    ____

    {'JBS'}    {'KZ'}    {'IP'}    {0×0 char}    2351     23       42     {0×0 char}    {0×0 char}    {0×0 char}    {0×0 char}    33      -0.0001     2596    153 
    {'MTK'}    {'KZ'}    {'IP'}    {0×0 char}    2351     26       60     {0×0 char}    {0×0 char}    {0×0 char}    {0×0 char}    29       0.0001     2623    154 
    {'SLT'}    {'KZ'}    {'IP'}    {0×0 char}    2351     28       57     {0×0 char}    {0×0 char}    {0×0 char}    {0×0 char}    28      -0.0001     2650    152 

[theo]

Thank you for the explanation, it really helps me understand the methods that I can use.

Thanks for your help, I really appreciate it