- [Instructor] In the previous movie,
I showed you how to write data to an external file.
In this movie,
I will show you how to read values from an external file
into a MATLAB variable.
I have just started MATLAB
and I have a clean command window ready to go.
So the first thing I need to do is create a file
with some values.
I'll start by defining a variable called mat1,
and then an equal sign for the assignment,
and I will create the first row
with the values four through 16
going up in increments of four.
So I'll type four then a colon,
my step value is four colon,
and the top value is 16.
Then a semicolon to indicate I have a new row,
and then we'll do five through 20
going up by five for the second row.
So five colon five colon 20.
Right square bracket and Enter,
and there I get my two by four matrix.
If I want to save these values in a file,
then I'd need to use the save function.
A space, then I will call the file matrixdata.dat.
I don't need to add the extension.
It can just be matrixdata.
But when someone looks at it in the current folder,
I want them to understand that it is a data file.
Press space.
The name of the variable I'm exporting is mat1.
Then a space,
and I want it to be text.
So we're representing text using the ASCII qualifiers,
so I'll type minus ascii.
And Enter.
And the file is created
and the values are saved there.
If I want to bring the data in,
I can do that using the load command.
So I'll type load space
and then the name of the file, matrixdata.dat,
and Enter,
and you see that I have the values
in the workspace in a variable named matrixdata.
So everything after the period was excluded for the name.
And if I type matrixdata in the command window
and press Enter,
then you see that I get the values back.
Normally you will work with much larger data sets than this,
but it's nice to know that the procedure works
for small files, as well.