mdfInfo

Access or create MDF-file metadata

Since R2019b

Syntax

fileInfo = mdfInfo(mdfFileName)

fileInfo = mdfInfo

Description

fileInfo = mdfInfo(mdfFileName) returns an MDFInfo object that contains information about the specified MDF-file, including name, location, version, size, initial timestamp of the data, and more. mdfFileName specifies an absolute, relative, or URL path to the MDF-file.

fileInfo = mdfInfo creates a default MDFInfo object that you can customize and use with mdfCreate to configure MDF-file metadata during file creation.

Examples

Access Information About MDF-File

Get the MDF-file information, and programmatically read its version.

fileInfo = mdfInfo("MDFFile.mf4");

fileInfo = 

  MDFInfo with properties:

   File Details
                  Name: "VehicleData.mf4"
                  Path: "E:\data\VehicleData.mf4"
                Author: ""
            Department: ""
               Project: ""
               Subject: ""
               Comment: "Example file with demo data."
               Version: "4.10"
      InitialTimestamp: 2022-01-20 01:22:34.000000000

   Creator Details
     ProgramIdentifier: "MATLAB"
     CreatorVendorName: "The MathWorks, Inc."
       CreatorToolName: "MATLAB"
    CreatorToolVersion: "9.12.0.1846952 (R2022a)"
       CreatorUserName: ""
        CreatorComment: ""

   File Contents
            Attachment: [1×8 table]
     ChannelGroupCount: 2

Read the Version property.

fileInfo.Version

ans =

    "4.10"

Create MDFInfo Object for New File

Create and modify an MDFInfo object for use in configuring a new MDF-file with customized metadata.

minfo = mdfInfo;
minfo.Comment = "25-Dec Shift B.";
%   ⋮
% Modify other properites as needed
%   ⋮
mdfCreate("MyMDFfile.mf4",FileInfo=minfo)

Input Arguments

mdfFileName — MDF-file name

string | char vector

MDF-file name, specified as a string or character vector, including the necessary full or relative path. You can use a URL to specify a file on a remote server.

Depending on the location you are accessing, mdfFileName can take one of these forms.

Location	Form
Current folder or MATLAB® path	To access a file in the current folder or MATLAB path, specify the name of the file in filename, including the file extension. Example: "myMdfFile.mf4"
Other folders	To access a file in a folder other than the current folder, specify the full or relative path name in filename. Example: "C:\myFolder\myMdfFile.mf4" Example: "\dataDir\myMdfFile.mf4"
Remote locations	To access a file in a remote location, filename must contain the full path of the file specified as a uniform resource locator (URL) of the form: scheme://path_to_file/myMdfFile.mf4 Based on the remote location, scheme can be one of the values in this table. Remote Location scheme Amazon S3™ s3 Windows Azure® Blob Storage wasb, wasbs HDFS™ hdfs For more information, see Work with Remote Data. Example: "s3://bucketname/path_to_file/myMdfFile.mf4"

Data Types: char | string

Output Arguments

fileInfo — MDF-file metadata information

MDFInfo object

MDF-file metadata information, returned as an MDFInfo object with the following properties:

MDFInfo Object Properties

Property Name	Data Type	Access
File Details
Name	string	Read-only
Path	string	Read-only
Author	string	Read/write
Department	string	Read/write
Project	string	Read/write
Subject	string	Read/write
Comment	string	Read/write
Version	string	Read/write
InitialTimestamp	datetime	Read/write
Creator Details
ProgramIdentifier	string	Read-only
CreatorVendorName	string	Read-only
CreatorToolName	string	Read-only
CreatorToolVersion	string	Read-only
CreatorUserName	string	Read/write
CreatorComment	string	Read/write
File Contents
Attachment	table	Read-only
ChannelGroupCount	uint64	Read-only

Version History

Introduced in R2019b

R2023a: mdfInfo Outputs an Object

In previous releases, mdfInfo generated a structure output. Starting in R2023a, the output is an MDFInfo object. This update is consistent with the update to the mdfCreate function input. Where possible, the properties of this object reflect the field names of the old structure output, so programmatic access might be unchanged. However a few changes might impact your workflow:

• Some properties of the MDFInfo object are read-only.

• The MDFInfo.Attachment property is now a table. You can access the first row of the table as MDFInfo.Attachment(1,:).

R2023a: Support for Remote File URLs

You can directly access MDF-file data stored at remote locations, including Amazon S3, Azure^® Blob Storage, and HDFS.