CombinedDatastore
Datastore to combine data read from multiple underlying datastores
Description
Use a CombinedDatastore object to combine the data read from
multiple other datastores.
A CombinedDatastore maintains parity between the underlying datastores,
so that data is read from corresponding parts of the underlying datastores. Resetting the
CombinedDatastore resets all of the underlying datastores.
Creation
You can create a CombinedDatastore object using the combine function.
For example, dsnew = combine(ds1,ds2) creates a datastore that combines the
read data from datastores ds1 and ds2.
Properties
Object Functions
combine | Combine data from multiple datastores |
hasdata | Determine if data is available to read |
preview | Preview subset of data in datastore |
read | Read data in datastore |
readall | Read all data in datastore |
writeall | Write datastore to files |
reset | Reset datastore to initial state |
transform | Transform datastore |
numpartitions | Number of datastore partitions |
partition | Partition a datastore |
shuffle | Shuffle all data in datastore |
isPartitionable | Determine whether datastore is partitionable |
isShuffleable | Determine whether datastore is shuffleable |
Examples
Combine Datastores
Create a datastore that maintains parity between the pair of images of the underlying datastores. For instance, create two separate image datastores, and then create a combined datastore that reads corresponding images from the two image datastores.
Create a datastore imds1 representing a collection of three images.
imds1 = imageDatastore({'street1.jpg','street2.jpg','peppers.png'}); Create a second datastore imds2 by transforming the images of imds1 to grayscale images.
imds2 = transform(imds1,@(x) rgb2gray(x));
Create a combined datastore from imds1 and imds2.
imdsCombined = combine(imds1,imds2);
Read the first pair of images from the combined datastore. Each read operation on this combined datastore returns a pair of images represented by a 1-by-2 cell array.
dataOut = read(imdsCombined)
dataOut=1×2 cell array
{480x640x3 uint8} {480x640 uint8}
Display the output of the first read from the combined datastore.
imshow(imtile(dataOut));
