Exporting Delimited ASCII Data Files :: Data Import and Export (Programming)

Programming

Exporting Delimited ASCII Data Files

To export an array as a delimited ASCII data file, you can use either the save function, specifying the -ASCII qualifier, or the dlmwrite function. The save function is easy to use; however, the dlmwrite function provides more flexibility, allowing you to specify any character as a delimiter and to export subsets of an array by specifying a range of values.

Using the save Function

To export the array A,

```
A = [ 1 2 3 4 ; 5 6 7 8 ];
```

use the save function, as follows:

```
save my_data.out A -ASCII
```

If you view the created file in a text editor, it looks like this:

1.0000000e+000  2.0000000e+000  3.0000000e+000  4.0000000e+000
5.0000000e+000  6.0000000e+000  7.0000000e+000  8.0000000e+000

By default, save uses spaces as delimiters but you can use tabs instead of spaces by specifying the -tabs option.

When you use save to write a character array to an ASCII file, it writes the ASCII equivalent of the characters to the file. If you write the character string 'hello' to a file, save writes the values

```
104 101 108 108 111
```

Using the dlmwrite Function

To export an array in ASCII format and specify the delimiter used in the file, use the dlmwrite function.

For example, to export the array A,

```
A = [ 1 2 3 4 ; 5 6 7 8 ];
```

as an ASCII data file that uses semicolons as a delimiter, use this command:

```
dlmwrite('my_data.out',A, ';')
```

If you view the created file in a text editor, it looks like this:

```
1;2;3;4
5;6;7;8
```

Note that dlmwrite does not insert delimiters at the end of rows.

By default, if you do not specify a delimiter, dlmwrite uses a comma as a delimiter. You can specify a space (' ') as a delimiter or, if you specify empty quotes (''), no delimiter.

Exporting Text Data Using the diary Function to Export Data