Exporting Text Data :: Data Import and Export (Programming)

Programming

Exporting Text Data

This section describes how to use MATLAB functions to export data in several common ASCII formats. For example, you can use these functions to export a MATLAB matrix as a text file where the rows and columns are represented as space-separated, numeric values. The function you use depends on the amount of data you want to export and its format. Topics covered include

If you are not sure which section describes your data, find the sample in the table below that most nearly matches the data format you want to create. Then read the section referred to in the table.

If you are familiar with MATLAB export functions but are not sure when to use them, see Table 6-4, which compares the features of each function.

Note If C or Fortran routines for writing data files in the form needed by other applications exist, create a MEX-file to write the data. See the MATLAB External Interfaces documentation for more information.

**Table 6-3: ASCII Data File Formats**
Data Format Sample	MATLAB Export Function
`1 2 3 4 5 6 7 8 9 10`	See Exporting Delimited ASCII Data Files and Using the diary Function to Export Data for information about these options.
`1; 2; 3; 4; 5; 6; 7; 8; 9; 10;`	See Exporting Delimited ASCII Data Files for information. The example shows a semicolon-delimited file, but you can specify another character as the delimiter.

**Table 6-4: ASCII Data Export Function Features**
Function	Use With	Delimiters	Notes
`csvwrite`	Numeric data	Commas only	Primarily used with spreadsheet data. See Working with Spreadsheets.
`diary`	Numeric data or cell array	Spaces only	Can be used for small arrays. Requires editing of data file to remove extraneous text.
`dlmwrite`	Numeric data	Any character	Easy to use, flexible.
`fprintf`	Alphabetic and numeric data	Any character	Part of low-level file I/O routines. This function is the most flexible but also the most difficult to use. You must use `fopen` to obtain a file identifier before writing the data and `fclose` to close the file after writing the data.
`save`	Numeric data	Tabs or spaces	Easy to use; output values are high precision.

Importing from XML Documents Exporting Delimited ASCII Data Files