I have of bunch of CSV files to read in Matlab. All of files has similar structure, except last field is optional. I.e. some files contain it, others are not.
Also files contain both textual and numeric fields, so csvread is not applicable.
Only alternative I know is textscan. Unfortunately, I can't find specifiers for optional fields.
I am looking at spec:
formatSpec = '%d%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%s%[^\n\r]';
and wish last %s be optional.
You could try the strsplit function
http://www.mathworks.com/help/matlab/ref/strsplit.html
To read a file line-by-line, you can use the function fgetl. It reads one line, removes newline-characters and returns the line as a string. At the end of the file, a -1 is returned.
You can then use the sscanf to extract the data according to your format spec (including the %s). If your input data doesn't contain any string at the end, then the last field was empty.
fid = fopen('file.txt','r');
while 1
line = fgetl(fid);
if line == -1
break;
end
A = sscanf(line,formatSpec);
...
end
You can then do whatever you need with A.
For example look at the following example:
line = '1 2.5 3.6 abc';
A = sscanf(line,'%d %f %f %s')
A =
1.0000
2.5000
3.6000
97.0000
98.0000
99.0000
The string will be A(4:end). The string was empty if isempty(A(4:end)), that way you can store the data as you like, e.g. in a cell.
Assuming you don't need the optional column, why not ignore the rest of the line by %*s and delimiter set to newline?
Related
I am trying to concatenate three lines (I want to leave the lines as is; 3 rows) from Shakespeare.txt file that shows:
To be,
or not to be:
that is the question.
My code right now is
fid = fopen('Shakespeare.txt')
while ~feof(fid)
a = fgets(fid);
b = fgets(fid);
c = fgets(fid);
end
fprintf('%s', strcat(a, b, c))
I'm supposed to use strcat and again, I want concatenated and leave them as three rows.
One method of keeping the rows separate is by storing the lines of the text file in a string array. Here a 1 by 3 string array is used. It may also be a good idea to use fgetl() which grabs each line of the text file at a time. Concantenating the outputs of fgetl() as strings may also be another option to ensure the they do not get stored as character (char) arrays. Also using the \n indicates to line break when printing the strings within the array String_Array.
fid = fopen('Shakespeare.txt');
while ~feof(fid)
String_Array(1) = string(fgetl(fid));
String_Array(2) = string(fgetl(fid));
String_Array(3) = string(fgetl(fid));
end
fprintf('%s\n', String_Array);
Ran using MATLAB R2019b
Dear All (with many thanks in advance),
The following script has trouble reading (and therefore writing) the %s character in the file 'master.py'.
I get that matlab thinks the %s is an escape character, so perhaps an option is to modify the terminator, but I have found this difficult.
(EDIT: Forgot to mention the file master.py is not in my control, so I can't modify the file to %%s for example).
%matlab script
%===============
fileID = fopen('script.py','w');
yMax=5;
fprintf(fileID,'yOverallDim = %d\n', -1*yMax);
%READ IN "master.py" for rest of script
fileID2 = fopen('master.py','r');
currentLine = fgets(fileID2);
while ischar(currentLine)
fprintf(fileID,currentLine);
currentLine = fgets(fileID2);
end
fclose(fileID);
fclose(fileID2);
The file 'master.py' looks like this (and the problem is on line 6 'setName ="Set-%s"%(i+1)':
i=0
for yPos in range (0,yOverallDim,yVoxelSize):
yCoordinate=yPos+(yVoxelSize/2) #
for xPos in range (0,xOverallDim,xVoxelSize):
xCoordinate=xPos+(xVoxelSize/2)
setName ="Set-%s"%(i+1)
p = mdb.models['Model-1'].parts['Part-1']
# p = mdb.models['Model-1'].parts['Part-2']
c = p.cells
cells = c.findAt(((xCoordinate, yCoordinate, 10.0), ))
region = p.Set(cells=cells, name=setName)
p.SectionAssignment(region=region, sectionName='Section-1', offset=0.0, offsetType=MIDDLE_SURFACE, offsetField='', thicknessAssignment=FROM_SECTION)
i+=1
In the documentation of fprintf you'll find this:
fprintf(fileID,formatSpec,A1,...,An) applies the formatSpec to all elements of arrays A1,...An in column order, and writes the data to a text file.
So in your function fprintf uses currentLine as format specification, resulting in an unexpected output for line 6. Correct application of fprintf by providing a formatSpec, fixes this issue and doesn't require any replace operations:
fprintf(fileID, '%s', currentLine);
Your script has no trouble reading the % characters correctly. The "problem" is with fprintf(). This function correctly interpretes the percent signs in the string as formatting characters. Therefore, I think you have to manually escape every single % character in your currentLine string:
currentLine = strrep(currentLine, '%', '%%');
At least, it worked when I checked it on your example data.
Thanks applesoup for identifying my fundamental oversight - the problem is in the fprintf - not in the file read
Thanks serial for enhancing the fprintf
I have a .txt file with rows consisting of three elements, a word and two numbers, separated by commas.
For example:
a,142,5
aa,3,0
abb,5,0
ability,3,0
about,2,0
I want to read the file and put the words in one variable, the first numbers in another, and the second numbers in another but I am having trouble with textscan.
This is what I have so far:
File = [LOCAL_DIR 'filetoread.txt'];
FID_File = fopen(File,'r');
[words,var1,var2] = textscan(File,'%s %f %f','Delimiter',',');
fclose(FID_File);
I can't seem to figure out how to use a delimiter with textscan.
horchler is indeed correct. You first need to open up the file with fopen which provides a file ID / pointer to the actual file. You'd then use this with textscan. Also, you really only need one output variable because each "column" will be placed as a separate column in a cell array once you use textscan. You also need to specify the delimiter to be the , character because that's what is being used to separate between columns. This is done by using the Delimiter option in textscan and you specify the , character as the delimiter character. You'd then close the file after you're done using fclose.
As such, you just do this:
File = [LOCAL_DIR 'filetoread.txt'];
f = fopen(File, 'r');
C = textscan(f, '%s%f%f', 'Delimiter', ',');
fclose(f);
Take note that the formatting string has no spaces because the delimiter flag will take care of that work. Don't add any spaces. C will contain a cell array of columns. Now if you want to split up the columns into separate variables, just access the right cells:
names = C{1};
num1 = C{2};
num2 = C{3};
These are what the variables look like now by putting the text you provided in your post to a file called filetoread.txt:
>> names
names =
'a'
'aa'
'abb'
'ability'
'about'
>> num1
num1 =
142
3
5
3
2
>> num2
num2 =
5
0
0
0
0
Take note that names is a cell array of names, so accessing the right name is done by simply doing n = names{ii}; where ii is the name you want to access. You'd access the values in the other two variables using the normal indexing notation (i.e. n = num1(ii); or n = num2(ii);).
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.
I have a file in the following format:
**400**,**100**::400,descendsFrom,**76**::0
**400**,**119**::400,descendsFrom,**35**::0
**400**,**4**::400,descendsFrom,**45**::0
...
...
Now I need to read, the part only in the bold. I've written the following formatspec:
formatspec = '%d,%d::%*d,%*s,%d::%*d\n';
data = textscan(fileID, formatspec);
It doesn't seem to work. Can someone tell me what's wrong?
I also need to know how to 'not use' delimiter, and how to proceed if I want to express the exact way my file is written in, for example in the case above.
EDITED
A possible problem is with the %s part of the formatspec variable. Because %s is an arbitrary string therefore the descendsFrom,76::0 part of the line is ordered to this string. So with the formatspec '%d,%d::%d,%s,%d::%d\n' you will get the following cells form the first line:
400 100 400 'descendsFrom,76::0'
To solve this problem you have two possibilities:
formatspec = %d,%d::%d,descendsFrom,%d::%d\n
OR
formatspec = %d,%d::%d,%12s,%d::%d\n
In the first case the 'descendForm' string has to be contained by each row (as in your example). In the second case the string can be changed but its length must be 12.
Your Delimiter is "," you should first delimit it then maybe run a regex. Here is how I would go about it:
fileID = fopen('file.csv');
D = textscan(fileID,'%s %s %s %s ','Delimiter',','); %read everything as strings
column1 = regexprep(D{1},'*','')
column2 = regexprep(D{2},{'*',':'},{'',''})
column3 = D{3}
column4 = regexprep(D{4},{'*',':'},{'',''})
This should generate your 4 columns which you can then combine
I believe the Delimiter can only be one symbol. The more efficient way is to directly do regexprep on your entire line, which would generate:
test = '**400**,**4**::400,descendsFrom,**45**::0'
test = regexprep(test,{'*',':'},{'',''})
>> test = 400,4400,descendsFrom,450
You can do multiple delimiters in textscan, they need to be supplied as a cell array of strings. You don't need the end of line character in the format, and you need to set 'MultipleDelimsAsOne'. Don't have MATLAB to hand but something along these lines should work:
formatspec = '%d %d %*d %*s %d %*d';
data = textscan(fileID, formatspec,'Delimiter',{',',':'},'MultipleDelimsAsOne',1);
If you want to return it as a matrix of numbers not a cell array, try adding also the option 'CollectOutput',1