I am a complete programming beginner trying to learn MATLAB. I want to extract numerical data from a bunch of different xml files. The numerical data items are bounded by the tags and . How do I write a program in MATLAB?
My algorithm:
1. Open the folder
2. Look into each of 50 xml files, one at a time
3. Where the tag <HNB.1></HNB.1> exists, copy numerical contents between said tag and write results into a new file
4. The new file name given for step 3 should be the same as the initial file name read in Step 2, being appended with "_data extracted"
example:
FileName = Stewart.xml
Contents = blah blah blah <HNB.1>2</HNB.1> blah blah
NewFileName = Stewart_data extracted.txt
Contents = 2
The fundamental function in MATLAB to read xml data is xmlread; but if you're a complete beginner, it can be tricky to work with just that. Try this series of blog postings that show you how to put it all together.
Suppose you want to read this file:
<PositiveSamples numImages="14">
<image numSubRegions="2" filename="TestingScene.jpg">
<subregion yStart="213" yEnd="683" xStart="1" xEnd="236"/>
<subregion yStart="196" yEnd="518" xStart="65" xEnd="226"/>
</image>
</PositiveSamples>
Then in matlab, read the file contents as follows:
%read xml file
xmlDoc = xmlread('PositiveSamples.xml');
%Get root element
root = xmlDoc.getDocumentElement();
%Read attributevale
numOfImages = root.getAttribute('numImages');
numOfImages = char(numOfImages);
numOfImages = uint16(eval(numOfImages));
Related
I have uploaded the file here. These are some lines from my txt file:
RSN1146_KOCAELI_AFY000 1.345178e-02
RSN1146_KOCAELI_AFY090 1.493577e-02
RSN1146_KOCAELI_AFYDWN 5.350641e-03
RSN4003_SANSIMEO_25862-UP 4.869095e-03
RSN4003_SANSIMEO_25862090 1.199087e-02
RSN4003_SANSIMEO_25862360 1.181286e-02
I would like to remove the data with DWN on 3rd line and -UP in 4th line. So the data will only have:
RSN1146_KOCAELI_AFY000 1.345178e-02
RSN1146_KOCAELI_AFY090 1.493577e-02
RSN4003_SANSIMEO_25862090 1.199087e-02
RSN4003_SANSIMEO_25862360 1.181286e-02
Then, I want to obtain the maximum value for RSN1146 & RSN4003.
I tried to read the file with the code below:
Data=fopen('maxPGA.txt','r');
readfile=fscanf(Data,'%c %s')
It is weird as I cannot perform further analysis as the data is not imported as 2 column in MATLAB, any solution for this?
I tried:
Data= importdata('maxPGA.txt')
as well, but the data are grouped into 2 different table in this case.
I have a main code named as process.m in which I define the path to 4 different .csv files for calculating values for each person. If I have a list of 30 persons and I don't want to define process.m as a function for each person, how can I do the processing for all the persons in one go. I want some idea by which process.m itself picks files for one person, then generate the results, then move to other person, pick his .csv files, generate the result and so on.
A breif outline of my code is attached here that would project the problem.
file1='Joseph_front.csv';
file2='Joseph_side.csv';
file3='Joseph_knee.csv';
file4='Joseph_back.csv';
A1=initiate2(file1); %initiate2 function reads the csv and perfoms some filtering operations on image in .csv format
A2=initiate2(file2);
A3=initiate2(file3);
A4=initiate2(file4);
%%omitted large part of code
cal(1) = p+q+r*s;
cal(2) = p+q+r+s;
cal(3) = p+q+r-s;
cal=cal'
%code to write the calculation in excel file
excelfile= 'test.xlsx';
xlswrite(excelfile,ValuesInInches,'Joseph_data',posColumn);
Describing more i want my code to process for 30 people all at once by selecting and picking the files itself, although i have done this operation by making the same code as a function for each person, but that is not very efficient as when I have to make a small change I have to make it in every function that means one change needs to be edited in 30 functions. Please suggest an efficient way to do it.
Note: All persons .csv files are named in the same manner and exist in the current folder.
I am assuming all of your files in one directory and there's no other files .
This portion of code will get the available filenames.
listFiles = dir('path of the directory');
filenames = strings; % an empty string array to save the filenames
j = 1;
for i = 1:1:length(listFiles)
if ~listFiles(i).isdir % to avoid the directory names
filenames(j,1) = listFiles(i).name;
j = j+1;
end
end
Now, there's 4 file for each person. So the loop should take 4 files at a time.
for ii = 1:4:length(filenames)
file1=filename(i);
file2=filename(i+1);
file3=filename(i+2);
file4=filename(i+3);
%% continue with your code
end
This question already has answers here:
Dynamically name a struct variable in MATLAB
(2 answers)
Closed 6 years ago.
I have a folder full of csv data files that I want to import to MATLAB. The import function will be the same for each of them. Their names follow a pattern, e.g. 'a0-b0.csv', 'a0-b5.csv', 'a0-b10.csv', 'a0-b15.csv' ... 'a2-b0' etc.
I want to import all these files at once. I want to import them as tables with sensible names that correspond to the data they contain.
Doing something like
filepath = 'file/path/'
for (a = [0, 2])
for (b = [0:5:50])
filename = strcat(filepath, 'a', num2str(a), '-b', num2str(b), '.csv')
varname = strcat('a', num2str(a), '_b', num2str(b))
varname = importfile(filename, startrow, endrow)
end
end
made sense in concept to me.
As 'varname' itself is the variable, not the string it contains, this does not do what I want. I've seen a lot of answers to similar situations suggesting eval(), while simultaneously vehemently advocating against it.
eval() has side effects that make it annoying to implement. Everyone's intense aversion to it make me wonder if it's worth putting in the effort to try to implement it.
I can think of no other way to do this, however. I don't see how using arrays (the recommended alternative) would result in appropriate/relevant names.
Does anyone have a suggestion as to how to automatically import many csv files to tables in MATLAB with names that correspond to their filenames?
(Regarding duplicates: I haven't yet found a question that addresses the automatic creation of corresponding variable names, which is the main issue here)
As #transversality condition wrote in their comment, you should rethink you approach.
I'd suggest two steps:
If you are about to change files in and import htem again, create .mat file with already imported data and check hwther to rescan the folder or load the .mat file.
Decide whether you want to use struct class or cell class to contain your data.
The code for struct can be:
filepath = 'file/path/'; % define the data folder
FileNames=dir('filepath\*.csv'); % list all csv. files within filepath
N=numel(FileNames); % count the csv files
DATA(N)=struct('name','','data',[]); % preallocate DATA
for (ii=1:N)
Temp=regexp(FileNames(ii).name,'\.','split'); % separate file name and abbreviation
DATA(ii).name = Temp{1}; % save the file name
DATA(ii).data = importfile([filepath,'\',FileNames(ii).name], startrow, endrow); % save the data
end
The code for cell can be:
filepath = 'file/path/'; % define the data folder
FileNames=dir('filepath\*.csv'); % list all csv. files within filepath
N=numel(FileNames); % count the csv files
DATA=cell(2,N); % preallocate DATA
for (ii=1:N)
Temp=regexp(FileNames(ii).name,'\.','split'); % separate file name and abbreviation
DATA{1,ii} = Temp{1}; % save the file name
DATA{2,ii} = importfile([filepath,'\',FileNames(ii).name], startrow, endrow); % save the data
end
In both cases you have to find the appropriate line by, for example, DATA(find(strcmpi(DATA.name,'<name>))).data.
You can also use the cell approach to create struct. Suppose we've run the code for cell.
Then command
DataStruct=struct(DATA{:});
will allow you to access your data via Data.Struct.<filename> command directly.
My requirement is read text files from content repository in sap abap.I used SCMS_DOC_READ FM to read image file and creating url DP_CREATE_URL for creating image url but SCMS_DOC_READ not working for text.
Can any one suggest some code, FM or class .
There are two options based on your requirement:
Option 1: Use READ DATASET to read file.
DATA : FNAME(60) type c VALUE 'myfile.txt',
TEXT2(5) type c.
OPEN DATASET FNAME FOR INPUT IN TEXT MODE.
DO.
READ DATASET FNAME INTO TEXT2 LENGTH LENG.
WRITE: / SY-SUBRC, TEXT2.
IF SY-SUBRC <> 0.
EXIT.
ENDIF.
ENDDO.
CLOSE DATASET FNAME.
Option 2: Use Class CL_ABAP_CONV_IN_CE to read file.
Refer this tutorial page to get more information on this class.
You can easily find the answer there: http://scn.sap.com/thread/525075
If you want the short answer, you should use this(Note: I am not the author of this part):
CALL FUNCTION 'GUI_UPLOAD'
EXPORTING
FILENAME = "File path"
FILETYPE = 'ASC'
HAS_FIELD_SEPARATOR = 'X'
TABLES
DATA_TAB = IT.
Note : Internal table structure should be same as text File.
I got this .nc file. However, when I read the file like this
ncid = netcdf.open(ncfile)
It gives me only a number. It was supposed to contain some data. I am not sure what's wrong with it. Can anyone please provide some information?
According to the documentation, netcdf.open only returns the NetCDF ID, not the data:
ncid = netcdf.open(source) opens source, which can be the name of a
NetCDF file or the URL of an OPeNDAP NetCDF data source, for read-only
access. Returns a NetCDF ID in ncid.
You probably want to use ncread.
Note:
ncid = netcdf.open(ncfile)
Where ncid is a netCDF file identifier returned by netcdf.create or
netcdf.open.
Eg : In your Case
ncid=netcdf.open(ncfile,'NC_NOWRITE');
varidp=netcdf.inqVarID(ncid,'varname'); //returns varid
Eg : Official
This example opens the example netCDF file included with MATLAB®, example.nc, and uses several inquiry functions to get the ID of the first variable.
ncid = netcdf.open('example.nc','NC_NOWRITE');
% Get information about first variable in the file.
[varname, xtype, dimids, atts] = netcdf.inqVar(ncid,0);
% Get variable ID of the first variable, given its name
varid = netcdf.inqVarID(ncid,varname)
Ref:http://www.mathworks.in/help/matlab/ref/netcdf.inqvarid.html
Thanks