I need to search a text file that is about 30 lines. I need it to search row by row and grab numbers based on their position in the text file that will remain constant throughout the text file. Currently I need to get the first 2 numbers and then the last 4 numbers of each row. My code now:
FileToOpen = fopen(textfile.txt)
if FileToOpen == -1
disp('Error')
return;
end
while true
msg = fgetl(FileToOpen)
if msg == -1
break;
end
end
I would like to use the fgetl command if possible as I somewhat know that command, but if their is an easier way that will be more than welcome.
This looks like a good start. You should be able to use msg - '0' to get the value of the numbers. For ascii code the digits are placed next to each other in the right order (0,1,2,3,4,5,6,7,8,9). What you do when you subtract with '0' is that you subtract msg with the ascii code of '0'. You will then get the digits as
tmp = msg - '0';
idx = find(tmp>=0 & tmp < 10); % Get the position in the row
val = tmp(idx); % Or tmp(tmp>=0 & tmp < 10) with logical indexing.
I agree that fgetl is probably the best to use for text without specific structure. However, in case you have a special structure of the text you can use that and thus be able to use more effective algorithms.
In case you was actually after finding the absolute position of the digits in the text, you can save the msgLength = msgLength + length(msg) for every iteration and use that to calculate the absolute position of the digits.
Related
I am generating 2500 values in Matlab in format (time,heart_rate, resp_rate) by using below code
numberOfSeconds = 2500;
time = 1:numberOfSeconds;
newTime = transpose(time);
number0 = size(newTime, 1)
% generating heart rates
heart_rate = 50 +(70-50) * rand (numberOfSeconds,1);
intHeartRate = int64(heart_rate);
number1 = size(intHeartRate, 1)
% hist(heart_rate)
% generating resp rates
resp_rate = 50 +(70-50) * rand (numberOfSeconds,1);
intRespRate = int64(resp_rate);
number2 = size(intRespRate, 1)
% hist(heart_rate)
% joining time and sensor data
joinedStream = strcat(num2str(newTime),{','},num2str(intHeartRate),{','},num2str(intRespRate))
dlmwrite('/Users/amar/Desktop/geenrated/rate.txt', joinedStream,'delimiter','');
The data shown in the console is alright, but when I save this data to a .txt file, it contains extra spaces in beginning. Hence I am not able to parse the .txt file to generate input stream. Please help
Replace the last two lines of your code with the following. No need to use strcat if you want a CSV output file.
dlmwrite('/Users/amar/Desktop/geenrated/rate.txt', [newTime intHeartRate intRespRate]);
πβπ π πππ’π‘πππ π π’ππππ π‘ππ ππ¦ ππΎπ ππ π‘βπ π ππππππ π‘ πππ π¦ππ’π πππ π. πβππ πππ π€ππ ππ₯ππππππ π€βπ¦ π¦ππ’ πππ‘ π‘βπ π’πππ₯ππππ‘ππ ππ’π‘ππ’π‘.
The data written in the file is exactly what is shown in the console.
>> joinedStream(1) %The exact output will differ since 'rand' is used
ans =
cell
' 1,60,63'
num2str basically converts a matrix into a character array. Hence number of characters in its each row must be same. So for each column of the original matrix, the row with the maximum number of characters is set as a standard for all the rows with less characters and the deficiency is filled by spaces. Columns are separated by 2 spaces. Take a look at the following smaller example to understand:
>> num2str([44, 42314; 4, 1212421])
ans =
2Γ11 char array
'44 42314'
' 4 1212421'
I want to use fscanf for reading a text file containing 4 rows with an unknown number of columns. The newline is represented by two consecutive spaces.
It was suggested that I pass : as the sizeA parameter but it doesn't work.
How can I read in my data?
update: The file format is
String1 String2 String3
10 20 30
a b c
1 2 3
I have to fill 4 arrays, one for each row.
See if this will work for your application.
fid1=fopen('test.txt');
i=1;
check=0;
while check~=1
str=fscanf(fid1,'%s',1);
if strcmp(str,'')~=1;
string(i)={str};
end
i=i+1;
check=strcmp(str,'');
end
fclose(fid1);
X=reshape(string,[],4);
ar1=X(:,1)
ar2=X(:,2)
ar3=X(:,3)
ar4=X(:,4)
Once you have 'ar1','ar2','ar3','ar4' you can parse them however you want.
I have found a solution, i don't know if it is the only one but it works fine:
A=fscanf(fid,'%[^\n] *\n')
B=sscanf(A,'%c ')
Z=fscanf(fid,'%[^\n] *\n')
C=sscanf(Z,'%d')
....
You could use
rawText = getl(fid);
lines = regexp(thisLine,' ','split);
tokens = {};
for ix = 1:numel(lines)
tokens{end+1} = regexp(lines{ix},' ','split'};
end
This will give you a cell array of strings having the row and column shape or your original data.
To read an arbitrary line of text then break it up according the the formating information you have available. My example uses a single space character.
This uses regular expressions to define the separator. Regular expressions powerful but too complex to describe here. See the MATLAB help for regexp and regular expressions.
AIR, ID
AIR.SIT
50 1 1 1 0 0 2 1
43.57 -116.24 1. 857.7
Hi, All,
I have a text file like above. Now in Matlab, I want to create 5000 text files, changing the number "2" (the specific number in the 3rd row) from 1 to 5000 in each file, while keeping other contents the same. In every loop, the changed number is the same with the loop number. And the output in every loop is saved into a new text file, with the name like AIR_LoopNumber.SIT.
I've spent some time writing on that. But it is kind of difficult for a newby. Here is what I have:
% - Read source file.
fid = fopen ('Air.SIT');
n = 1;
textline={};
while (~feof(fid))
textline(n,1)={fgetl(fid)};
end
FileName=Air;
% - Replace characters when relevant.
for i = 1 : 5000
filename = sprintf('%s_%d.SIT','filename',i);
end
Anybody can help on finishing the program?
Thanks,
James
If your file is so short you do not have to read it line by line. Just read the full thing in one variable, modify only the necessary part of it before each write, then write the full variable back in one go.
%% // read the full file as a long sequence of 'char'
fid = fopen ('Air.SIT');
fulltext = fread(fid,Inf,'char') ;
fclose(fid) ;
%% // add a few blank placeholder (3 exactly) to hold the 4 digits when we'll be counting 5000
fulltext = [fulltext(1:49) ; 32 ; 32 ; 32 ; fulltext(50:end) ] ;
idx2replace = 50:53 ; %// save the index of the characters which will be modified each loop
%% // Go for it
baseFileName = 'AIR_%d.SIT' ;
for iFile = 1:1000:5000
%// build filename
filename = sprintf(baseFileName,iFile);
%// modify the string to write
fulltext(idx2replace) = num2str(iFile,'%04d').' ; %//'
%// write the file
fidw = fopen( filename , 'w' ) ;
fwrite(fidw,fulltext) ;
fclose(fidw) ;
end
This example works with the text in your example, you may have to adjust slightly the indices of the characters to replace if your real case is different.
Also I set a step of 1000 for the loop to let you try and see if it works without writing 1000's of file. When you are satisfied with the result, remove the 1000 step in the for loop.
Edit:
The format specifier %04d I gave in the first solution insure the output will take 4 characters, and it will pad any smaller number with zero (ex: 23 => 0023). It is sometimes desirable to keep the length constant, and in your particular example it made things easier because the output string would be exactly the same length for all the files.
However it is not mandatory at all, if you do not want the loop number to be padded with zero, you can use the simple format %d. This will only use the required number of digits.
The side effect is that the output string will be of different length for different loop number, so we cannot use one string for all the iterations, we have to recreate a string at each iteration. So the simple modifications are as follow. Keep the first paragraph of the solution above as is, and replace the last 2 paragraphs with the following:
%% // prepare the block of text before and after the character to change
textBefore = fulltext(1:49) ;
textAfter = fulltext(51:end) ;
%% // Go for it
baseFileName = 'AIR_%d.SIT' ;
for iFile = 1:500:5000
%// build filename
filename = sprintf(baseFileName,iFile);
%// rebuild the string to write
fulltext = [textBefore ; num2str(iFile,'%d').' ; textAfter ]; %//'
%// write the file
fidw = fopen( filename , 'w' ) ;
fwrite(fidw,fulltext) ;
fclose(fidw) ;
end
Note:
The constant length of character for a number may not be important in the file, but it can be very useful for your file names to be named AIR_0001 ... AIR_0023 ... AIR_849 ... AIR_4357 etc ... because in a list they will appear properly ordered in any explorer windows.
If you want your files named with constant length numbers, the just use:
baseFileName = 'AIR_%04d.SIT' ;
instead of the current line.
I have a large text file (~3500 lines) which contains output data from an instrument. This consists of repeated entries from different measurements which are all formatted as follows:
* LogFrame Start *
variablename1: value
variablename2: value
...
variablename35: value
* LogFrame End *
Each logframe contains 35 variables. From these I would like to extract two, 'VName' and 'EMGMARKER' and put the associated values in columns in a matlab array, (i.e. the array should be (VName,EMGMARKER) which I can then associate with data from another output file which I already have in a matlab array. I have no idea where to start with this in order to extract the variables from this file, so hence my searches on the internet so far have been unsuccessful. Any advice on this would be much appreciated.
You could use textscan:
C = textscan(file_id,'%s %f');
Then you extract the variables of interest like this:
VName_indices = strcmp(C{1},'VName:');
VName = C{2}(VName_indices);
If the variable names, so 'VName' and 'EMGMARKER' , are always the same you can just read through the file and search for lines containing them and extract data from there. I don't know what values they contain so you might have to use cells instead of arrays when extracting them.
fileID = fopen([target_path fname]); % open .txt file
% read the first line of the specified .txt file
current_line = fgetl(fileID);
counter = 1;
% go through the whole file
while(ischar(current_line))
if ~isempty(strfind(current_line, VName))
% now you find the location of the white space delimiter between name and value
d_loc = strfind(current_line,char(9));% if it's tab separated - so \t
d_loc = strfind(current_line,' ');% if it's a simple white space
variable_name{counter} = strtok(current_line);% strtok returns everything up until the first white space
variable_value{counter} = str2double(strtok(current_line(d_loc(1):end)));% returns everything form first to second white space and converts it into a double
end
% same block for EMGMARKER
counter = counter+1;
current_line = fgetl(fileID);% next line
end
You do the same for EMGMARKER and you have cells containing the data you need.
I would like to modify a string that will have make the first letter capitalized and all other letters lower cased, and anything else will be unchanged.
I tried this:
function new_string=switchCase(str1)
%str1 represents the given string containing word or phrase
str1Lower=lower(str1);
spaces=str1Lower==' ';
caps1=[true spaces];
%we want the first letter and the letters after space to be capital.
strNew1=str1Lower;
strNew1(caps1)=strNew1(caps1)-32;
end
This function works nicely if there is nothing other than a letter after space. If we have anything else for example:
str1='WOW ! my ~Code~ Works !!'
Then it gives
new_string =
'Wow My ^code~ Works !'
However, it has to give (according to the requirement),
new_string =
'Wow! My ~code~ Works !'
I found a code which has similarity with this problem. However, that is ambiguous. Here I can ask question if I don't understand.
Any help will be appreciated! Thanks.
Interesting question +1.
I think the following should fulfil your requirements. I've written it as an example sub-routine and broken down each step so it is obvious what I'm doing. It should be straightforward to condense it into a function from here.
Note, there is probably also a clever way to do this with a single regular expression, but I'm not very good with regular expressions :-) I doubt a regular expression based solution will run much faster than what I've provided (but am happy to be proven wrong).
%# Your example string
Str1 ='WOW ! my ~Code~ Works !!';
%# Convert case to lower
Str1 = lower(Str1);
%# Convert to ascii
Str1 = double(Str1);
%# Find an index of all locations after spaces
I1 = logical([0, (Str1(1:end-1) == 32)]);
%# Eliminate locations that don't contain lower-case characters
I1 = logical(I1 .* ((Str1 >= 97) & (Str1 <= 122)));
%# Check manually if the first location contains a lower-case character
if Str1(1) >= 97 && Str1(1) <= 122; I1(1) = true; end;
%# Adjust all appropriate characters in ascii form
Str1(I1) = Str1(I1) - 32;
%# Convert result back to a string
Str1 = char(Str1);