hasdata

Determine if data is available to read

Syntax

tf = hasdata(ds)

Description

tf = hasdata(ds)returns logical1(true) if there is data available to read from the datastore specified byds. Otherwise, it returns logical0(false).

Examples

collapse all

Determine if Data is Available to Read

Open Live Script

Create a datastore from the sample file,mapredout.mat, which is the output file of themapreducefunction.

ds = datastore('mapredout.mat');

While there is data available in the datastore, read the data.

whilehasdata(ds) T = read(ds);end

Input Arguments

collapse all

`ds`—Input datastore
datastore

Input datastore. You can use these datastores as input to thehasdatamethod.

MATLAB^®datastores — Datastores created using MATLABdatastorefunctions. For example, create a datastore for a collection of images usingImageDatastore. For a complete list of datastores, seeSelect Datastore for File Format or Application.
Combined or transformed datastores — Datastores created using thecombineandtransformfunctions.
Custom datastores — Datastores created using the custom datastore framework. SeeDevelop Custom Datastore.

Extended Capabilities

Thread-Based Environment
Run code in the background using MATLAB®`backgroundPool`or accelerate code with Parallel Computing Toolbox™`ThreadPool`.

Usage notes and limitations:

In a thread-based environment, you can usehasdataonly with the following datastores:
- ImageDatastoreobjects
- CombinedDatastoreorTransformedDatastoreobjects you create fromImageDatastoreobjects by usingcombineortransform
You can usehasdatawith other datastores if you have Parallel Computing Toolbox™. To do so, run the function using a process-backed parallel pool instead of usingbackgroundPoolorThreadPool(use eitherProcessPoolorClusterPool).

For more information, seeRun MATLAB Functions in Thread-Based Environment.

Version History

Introduced in R2014b