MATLAB: How to read a text file as fixed width columns

Hello,

I have a traffic cards with information about traffic every 15 minutes, over one year I will have 2500 rows in every card. each row must be divided into 25 columns with a fixed width as shown in the next line.

Column widths: 1 2 6 1 1 2 2 2 2 4 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 how can I do this in matlab please?

Best Answer

cw=[1 2 6 1 1 2 2 2 2 4 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5];
fmt=sprintf('%%%dd',cw);
% file open preamble code here for opening file, return valid fid
data=cell2mat(textscan(fid,fmt,'collectoutput',1));

Above presumes all are integer fields, if data does include floating point values fix up format fields to match.

PS: Do not use user ids for tags in future...

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fid = fopen('YourFile.txt', 'rt');
datacell = textscan(fid, '%s%*s%*s%*s%s', 'CollectOutput', true);
fclose(fid);
data_to_print = [{'ln Temp', 'Time'}; datacell{1}] .';  %transpose is important
fmt = '%8s%15s\n';
fid = fopen('NewFile.txt', 'wt');
fprintf(fid, fmt, data_to_print{:});
fclose(fid);

MATLAB: Function data into columns

When you do

if isinteger(x)
   ((x)^(n)/factorial(n))
else 
   exp(x)
end

then you compute either ((x)^(n)/factorial(n)) or exp(x) . Because there is no semi-colon after the computation, the default action is taken with the result, and that default action is to display the value. But you are not storing the value -- which is something you need to do because you need to return computed values.

Hint: you probably need to read http://www.mathworks.com/help/matlab/learn_matlab/array-indexing.html

Other notes:

you cannot use a vector of values "^" something. You need to use the vector ".^" the somethng. Not x^n but x.^n . This is because in MATLAB, the "^" operator is matrix exponentiation not element-by-element exponentiation.
Your "while" condition is only going to be executed once. You start with n = 0, and use "while n<1" so it will be true the first time. Then you have n = n + 1 so the 0 will become 1, which is not <1 so the while will not be true the second time. It seems more likely to me that you want to use a "for" loop running up to the maximum order you have defined to expand to (order 6 is pretty common)
isinteger() does not test whether its input has integral value: it test whether the input is one of the integer data types, such as uint8 or int32
you are testing the entire vector x at one time, not individual entries in x
but why are you testing if x is integral anyhow?

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