filenames2labels
Syntax
Description
creates a list of labels based on the filenames contained in lbls
= filenames2labels(ds
)ds
.
ds
can be a datastore, matlab.io.datastore.FileSet
object, or matlab.io.datastore.BlockedFileSet
object.
specifies additional name-value arguments. For example,
lbls
= filenames2labels(___,Name=Value
)IncludeSubfolders=true
includes subfolders in the scan for
labels.
Examples
Labels from Filenames in Folder
Specify the folder that contains sample audio signals included with Signal Processing Toolbox™.
audiofolder = "audiodata";
Create a list of labels based on the .wav
filenames located in folder
.
lbls = filenames2labels(audiofolder,FileExtensions=".wav")
lbls = 3x1 categorical
GuitarTuneSignal
NoisyMusicSignal
SpeechDFTSignal
Labels from Filenames in Datastore
Download a publicly available data set of ultra-wideband (UWB) impulse radar signals [1]. The data set contains recordings of dynamic hand gestures collected from human volunteers and is divided into eight subfolders.
datasetZipFolder = matlab.internal.examples.downloadSupportFile("SPT","data/uwb-gestures.zip"); datasetFolder = erase(datasetZipFolder,".zip"); if ~exist(datasetFolder,"dir") downloadLocation = fileparts(datasetZipFolder); unzip(datasetZipFolder,downloadLocation); end
Create a signal datastore that points to the files located in the download folder. Include subfolders in the search path.
ds = signalDatastore(datasetFolder,IncludeSubfolders=true);
Create a list of labels based on the filenames contained in the datastore. Extract only the substring of the filename that includes the gesture code (G1, G2, ..., G12). Verify that each of the eight subfolders contains one file corresponding to each gesture.
p = "G"+digitsPattern;
lbls = filenames2labels(ds,Extract=p);
countlabels(lbls)
ans=12×3 table
Label Count Percent
_____ _____ _______
G1 8 8.3333
G10 8 8.3333
G11 8 8.3333
G12 8 8.3333
G2 8 8.3333
G3 8 8.3333
G4 8 8.3333
G5 8 8.3333
G6 8 8.3333
G7 8 8.3333
G8 8 8.3333
G9 8 8.3333
For an example that classifies the different hand gestures using a convolutional neural network (CNN), see Hand Gesture Classification Using Radar Signals and Deep Learning.
References
[1] Ahmed, Shahzad, Dingyang Wang, Junyoung Park, and Sung Ho Cho. "UWB-Gestures, a Public Dataset of Dynamic Hand Gestures Acquired Using Impulse Radar Sensors." Scientific Data 8, no. 1 (April 12,2021): 102. https://doi.org/10.1038/s41597-021-00876-0.
Input Arguments
loc
— Files or folders to scan for labels
character vector | cell array of character vectors | string scalar | string array
Files or folders to scan for labels, specified as a character vector, a cell array of character vectors, a string scalar, or a string array, containing the location of files or folders that are local or remote.
Local files or folders — Specify
loc
as a local path to files or folders. If the files are not in the current folder, the local path must specify full or relative paths. Files within subfolders of the specified folder are included by default. You can use the wildcard character (*
) when specifying the local path. This character specifies that the file search include all matching files or all files in the matching folders.A remote location specified using an internationalized resource identifier (IRI).
Remote files or folders — Specify
loc
to be the full paths of the files or folders as a uniform resource locator (URL) of the formhdfs:///path_to_file
. For more information, see Work with Remote Data.
filenames2labels
looks for all file formats. To specify a
custom list of file extensions to scan, use the FileExtensions
argument.
Example: 'whale.mat'
Example: '../dir/data/signal.mat'
Example: "../dir/data/"
Example: {'dataFiles/Files_1/'
'dataFiles/Files_2/'}
Example: ["dataFiles/Files_1/"
"dataFiles/Files_2/"]
Data Types: char
| string
| cell
ds
— Data repository
datastore | matlab.io.datastore.FileSet
object | matlab.io.datastore.BlockedFileSet
object
Data repository, specified as a datastore,
matlab.io.datastore.FileSet
object, or
matlab.io.datastore.BlockedFileSet
object.
If you specify a datastore, then
ds
must contain aFiles
property from which label names are parsed.If you specify a
matlab.io.datastore.FileSet
object, the function obtains label names from the filenames listed in theFileInfo
property ofds
.If you specify a
matlab.io.datastore.BlockedFileSet
object, the function obtains the label names from the filenames in theBlockInfo
property ofds
.
Name-Value Arguments
Specify optional pairs of arguments as
Name1=Value1,...,NameN=ValueN
, where Name
is
the argument name and Value
is the corresponding value.
Name-value arguments must appear after other arguments, but the order of the
pairs does not matter.
Before R2021a, use commas to separate each name and value, and enclose
Name
in quotes.
Example: filenames2labels(loc,"ExtractBetween",[5 8])
FileExtensions
— File extensions
character vector | cell array of character vectors | string scalar | string vector
File extensions, specified as a string scalar, string vector, character vector, or
cell array of character vectors. If you do not specify
FileExtensions
, the function includes the filenames of all
files found in the specified location in the list of labels.
This argument applies only when the input is a file location.
Example: [".mat" ".csv"]
Data Types: char
| string
| cell
IncludeSubFolders
— Subfolder inclusion flag
true
or 1
(default) | false
or 0
Subfolder inclusion flag, specified as true
or
false
. If you specify IncludeSubFolders
as
true
, the function includes subfolders in the scan for
labels.
This argument applies only when the input is a file location.
Data Types: double
| logical
ExtractBefore
— Delimiter that marks end position for extracted substring
string scalar | pattern
object | positive integer
Delimiter that marks the end position for the extracted substring, specified as a
string scalar, pattern
object, or positive integer.
If you specify a string or
pattern
object, the function extracts labels from each filename as the substring that begins with the first character of the filename and ends before the first occurrence of the delimiter string or pattern.If you specify a positive integer, the function extracts labels from each filename as the substring that begins with the first character of the filename and ends before the position specified by the delimiter index.
If the string or pattern
object is not found in a
filename, or if the index is 1 or larger than length(char(filename))+1, the function sets the label for that filename to
undefined
.
Example: 3
Example: "S"
Example: digitsPattern + "_"
Data Types: double
| char
| string
ExtractAfter
— Delimiter that marks start position for extracted substring
string scalar | pattern
object | nonnegative integer
Delimiter that marks the start position for the extracted substring, specified as
a string scalar, pattern
object, or nonnegative integer.
If you specify a string or
pattern
object, the function extracts labels from each filename as the substring that begins after the first occurrence of the delimiter string or pattern and ends with the last character of the filename.If you specify a nonnegative integer, the function extracts labels from each filename as the substring that begins after the position specified by the delimiter index and ends with the last character of the filename.
If the string or pattern
object is not found in a
filename, or if the index is larger than or equal to length(char(filename))+1, the function sets the label for that filename to
undefined
.
Example: 2
Example: "Subject"
Example: "_" + wildcardPattern
Data Types: double
| char
| string
ExtractBetween
— Delimiter that marks start and end positions for extracted substring
two-element string vector | two-element cell array of characters | two-element vector of pattern
objects | two-element vector of positive integers
Delimiter that marks the start and end positions for the extracted substring,
specified as a two-element string vector or cell array of characters, a two-element
vector of pattern
objects, or a two-element vector of positive
integers. For a delimiter equal to [P S]
:
If you specify a two-element string or cell array of characters, or a two-element vector of
pattern
objects, the function extracts labels from each filename as the substring that begins afterP
and ends beforeS
.If you specify a two-element vector of positive integers, the function extracts labels from each filename as the characters indexed by
P:S
.S
must be larger than or equal toP
.
If there are no characters between [P S]
, or if
indices P
or S
are larger than the length of the
filename, the function sets the label for that filename to
undefined
.
Example: [3 7]
Example: ["A" "D"]
Example: ["_" "_"]
Data Types: double
| char
| string
| cell
Extract
— Delimiter to find substring
pattern
object
Delimiter to find substring, specified as a pattern
object. The function extracts labels from each filename as the substring that matches
the pattern
object.
If no match is found in a filename, the function sets the label for that filename to
undefined
.If more than one pattern is found per filename, the function returns
lbls
as a matrix. All filenames must have the same number of pattern matches.
Example: lettersPattern
Example: "_" + wildcardPattern + "_"
Output Arguments
files
— List of files
string vector
List of files used to scan for labels, returned as a string vector. The
ith file in files
corresponds to the
ith label in lbls
.
Version History
Introduced in R2022b
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