MATLAB Programming

6 Data Import and Export
• rowheaders—Column vector containing the names of all row headers.
• colheaders—Row vector containing the names of all column headers.
• textdata—Matrix containing all imported text data. Empty elements
are set to ''.
• data—Matrix containing all imported numeric data. Empty elements are
set to NaN.
If the imported file or clipboard contains only numeric or only text data, then
the Import Wizard does not use the variable names shown above. Instead, it
assignsallofthedatatojustonevariable:
• For data imported from a text file, the name of the variable is the same as
thefilename,minusthefileextension.
• For data imported from the clipboard, the name of the variable is
A_pastespecial.
Specifying Delimiters and Header Format [Text only]
Using the options shown at the top of the Import Wizard dialog box, you can
specify a delimiter character for separating data items, and also the number
of lines you want to use for column headers.
Delimiters
Most text files use a unique character called a delimiter or column separator
to mark the separation between items of data. For example, data in a
comma-separated value (CSV) file is, of course, separated by commas. Data in
some other file might be separated by tab or space characters.
When the Import Wizard imports from a text file or the clipboard, it makes its
best guess as to which character was intended as the delimiter and displays
the data accordingly. If this is not correct, you will need to set the correct
delimiter from the choices shown under Select Column Separator(s)
in the upper left of the dialog box. When you do this, the Import Wizard
immediately reformats the data, displaying new values for the data shown
in the preview pane.
6-12