I was trying to read a csv file with ezread https://de.mathworks.com/matlabcentral/fileexchange/11026-ezread and I get the following problem:
Error using textscan
The second input must be a format character vector containing at least one >specifier or a literal field.
Error in ezread (line 66)
data = textscan(fid,format_str,'delimiter',file_delim,'headerlines',1);
I call the function as follows:
tmpName = '/path/file.csv';
structRead = ezread(tmpName, 'r');
I have checked if tmpName is correct with isfile(), so it is a correct path.
First two rows of my file have the following format:
a,b,c,d
1,2,e,f
Do you know where the problem could be ?
Instead ezread, you should use importdata. However it will not recognize separation on comma ,. So you need to add extra line:
tmpName = importdata('/path/file.csv');
structRead = split(a, ',')
The result is:
2×4 cell array
{'a'} {'b'} {'c'} {'d'}
{'1'} {'2'} {'e'} {'f'}
Related
I have a deco.csv file and I only want to extract B1 to K1 (20 columns of the first rows), i.e. Deco_0001 to Deco_0020.
I first make a pre-allocation:
names = string(20,1);
and what I want is when calling S(1), it gives Deco_0001; when calling S(20), it gives Deco_0020.
I have read through textscan but I do not know how to specify the range is first row and running from column 2 to column 21 of the csv file.
Also, I want save the names individually but what I have tried just save the first line in only one cell:
fid=fopen('deco.csv');
C=textscan(fid, '%s',1);
fclose(fid);
Thanks!
It's not very elegant, but this should work for you:
fid=fopen('deco.csv');
C=textscan(fid, '%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s',1,'Delimiter',',');
fclose(fid);
S = cell(20,1);
for ii = 1:20
S{ii} = C{ii+1};
end
how do I insert a string into a csv file in matlab. i used this code to write some data and create my csv file:
and here is the output of the code:
I'm trying to insert some text in the first 2 columns before the numerical data..
thanks in advance :)
There are several approaches are possible here.
Let's take a look at some of them:
If you need to add string to your csv file.
For example, I create some csv file like your:
q = [1 2 3 4 5 6 7];
csvwrite('csvlist4.csv',q,2,0);
All troubles is to add some string to csv - it's because we need to combine numeric and text data. There are no good functions for it in Matlab except low levels:
c = 'some big text';
fid = fopen('csvlist4.csv','r+');
fprintf(fid,c);
How it works: the data in csv is an array. I put data in 3rd row, so first and second is an empty but they have ','. When you use fprintf it will replace this , with your text. So if text is too long it will overwrite your data.
How to avoid this?
Easiest way - is to do it with help of xlswrite function. For your example:
txt = cell(size(Q))
txt{1} = 'this is your text'
X = [txt; num2cell(Q)]
xlswrite('new.xlsx',X)
Result:
Important moment here: number of cell for text must be the same as your data. But I filled with the text only first cell in my example.
And the one more way: read csv file, modify it's data and write to csv:
csvwrite('csvlist4.csv',a,2,0);
m = csvread('csvlist4.csv');
fid = fopen('csvlist4.csv','w');
c = 'your text'
fprintf(fid, c); fprintf(fid, '\n');
fclose(fid);
dlmwrite('csvlist4.csv', m(3:end,:), '-append');
Of course you can use cell array instead c and so on and so on.
Hope it helps!
I have the following sample from a CSV file. Structure is:
Date ,Time(Hr:Min:S:mS), Value
2015:08:20,08:20:19:123 , 0.05234
2015:08:20,08:20:19:456 , 0.06234
I then would like to read this into a matrix in MATLAB.
Attempt :
Matrix = csvread('file_name.csv');
Also tried an attempt formatting the string.
fmt = %u:%u:%u %u:%u:%u:%u %f
Matrix = csvread('file_name.csv',fmt);
The problem is when the file is read the format is wrong and displays it differently.
Any help or advice given would be greatly appreciated!
EDIT
When using #Adriaan answer the result is
2015 -11 -9
8 -17 -1
So it seems that MATLAB thinks the '-' is the delimiter(separator)
Matrix = csvread('file_name.csv',1,0);
csread does not support a format specifier. Just enter the number of header rows (I took it to be one, as per example), and number of header columns, 0.
You file, however, contains non-numeric data. Thus import it with importdata:
data = importdata('file_name.csv')
This will get you a structure, data with two fields: data.data contains the numeric data, i.e. a vector containing your value. data.textdata is a cell containing the rest of the data, you need the first two column and extract the numerics from it, i.e.
for ii = 2:size(data.textdata,1)
tmp1 = data.textdata{ii,1};
Date(ii,1) = datenum(tmp1,'YYYY:MM:DD');
tmp2 = data.textdata{ii,2};
Date(ii,2) = datenum(tmp2,'HH:MM:SS:FFF');
end
Thanks to #Excaza it turns out milliseconds are supported.
I am reading in a .txt-file using importdata:
MC_file = importdata('D:\Simon\Dropbox\SGM\Gigerwald\Results\Multi_SGM_10000.txt');
Data = MC_file.data
Header = MC_file.colheaders
which gives me a struct-variable with the header and the data-body:
data = 10000x52 double
colheaders = 1x52 cell
Now i'd like to change the data, i.e. add some columns to the end of the file and then print the file again with the same header + 5 new columns.
The body can be printed easily using dlmwrite(), e.g. like this:
dlmwrite('SGM.txt',Data,'precision',8,'delimiter','\t','newline','pc','-append')
...but how do I print the header into the file, of which I have a array of cells? I've seen this, but since I end up with 57 columns hard-coding is not an option...
The solution is attainable using repmat. Assuming that your file is tab separated, you can use:
NUM_COLS = 57;
A=cellstr(num2str((1:NUM_COLS)'))';
fid=fopen('newfile.txt','w');
fprintf(fid,repmat('%s\t ',[1,NUM_COLS]),A{:});
fclose(fid);
The result can be previewed with:
sprintf(repmat('%s\t ',[1,NUM_COLS]),A{:})
The following code generates a similar dataset to what I am currently working with:
clear all
a = rand(131400,12);
DateTime=datestr(datenum('2011-01-01 00:01','yyyy-mm-dd HH:MM'):4/(60*24):...
datenum('2011-12-31 23:57','yyyy-mm-dd HH:MM'),...
'yyyy-mm-dd HH:MM');
DateTime=cellstr(DateTime);
header={'DateTime','temp1','temp2','temp4','temp7','temp10',...
'temp13','temp16','temp19','temp22','temp25','temp30','temp35'};
I'm trying to convert the outputs into one variable (called 'Data'), i.e. have header as the first row (1,:), 'DateTime' starting from row 2 (2:end,1) and running through each row, and finally having 'a' as the data (2:end,2:end) if that makes sense. So, 'DateTime' and 'header' are used as the heading for the rows and column respectively. Following this I need to save this into a tab delimited text file.
I hope I've been clear in expressing what I'm attempting.
An easy way, but might be not the fastest:
Data = [header; DateTime, num2cell(a)];
filename = 'test.txt';
dlmwrite(filename,1); %# no create text file, not Excel
xlswrite(filename,Data);
UPDATE:
It appears that xlswrite actually changes the format of DateTime values even if it writes to a text file. If the format is important here is the better and actually faster way:
filename = 'test.txt';
out = [DateTime, num2cell(a)];
out = out'; %# our cell array will be printed by columns, so we have to transpose
fid = fopen(filename,'wt');
%# printing header
fprintf(fid,'%s\t',header{1:end-1});
fprintf(fid,'%s\n',header{end});
%# printing the data
fprintf(fid,['%s\t', repmat('%f\t',1,size(a,2)-1) '%f\n'], out{:});
fclose(fid);