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paddlepaddle--paddle/python/paddle/vision/datasets/folder.py
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2026-07-13 12:40:42 +08:00

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Python

# Copyright (c) 2020 PaddlePaddle Authors. All Rights Reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
from __future__ import annotations
from typing import TYPE_CHECKING, Any, Literal, TypeAlias
if TYPE_CHECKING:
from collections.abc import Callable, Sequence
from paddle._typing.dtype_like import _DTypeLiteral
from paddle.vision.transforms.transforms import _Transform
from ..image import _ImageDataType
_AllowedExtensions: TypeAlias = Literal[
'.jpg',
'.jpeg',
'.png',
'.ppm',
'.bmp',
'.pgm',
'.tif',
'.tiff',
'.webp',
]
import os
from PIL import Image
import paddle
from paddle.io import Dataset
from paddle.utils import try_import
__all__ = []
def has_valid_extension(filename: str, extensions: Sequence[str]) -> bool:
"""Checks if a file is a valid extension.
Args:
filename (str): path to a file
extensions (list[str]|tuple[str]): extensions to consider
Returns:
bool: True if the filename ends with one of given extensions
"""
assert isinstance(extensions, (list, tuple)), (
"`extensions` must be list or tuple."
)
extensions = tuple([x.lower() for x in extensions])
return filename.lower().endswith(extensions)
def make_dataset(dir, class_to_idx, extensions, is_valid_file=None):
images = []
dir = os.path.expanduser(dir)
if extensions is not None:
def is_valid_file(x):
return has_valid_extension(x, extensions)
for target in sorted(class_to_idx.keys()):
d = os.path.join(dir, target)
if not os.path.isdir(d):
continue
for root, _, fnames in sorted(os.walk(d, followlinks=True)):
for fname in sorted(fnames):
path = os.path.join(root, fname)
if is_valid_file(path):
item = (path, class_to_idx[target])
images.append(item)
return images
class DatasetFolder(Dataset[tuple["_ImageDataType", int]]):
"""A generic data loader where the samples are arranged in this way:
.. code-block:: text
root/class_a/1.ext
root/class_a/2.ext
root/class_a/3.ext
root/class_b/123.ext
root/class_b/456.ext
root/class_b/789.ext
Args:
root (str): Root directory path.
loader (Callable|None, optional): A function to load a sample given its path. Default: None.
extensions (list[str]|tuple[str]|None, optional): A list of allowed extensions.
Both :attr:`extensions` and :attr:`is_valid_file` should not be passed.
If this value is not set, the default is to use ('.jpg', '.jpeg', '.png',
'.ppm', '.bmp', '.pgm', '.tif', '.tiff', '.webp'). Default: None.
transform (Callable|None, optional): A function/transform that takes in
a sample and returns a transformed version. Default: None.
is_valid_file (Callable|None, optional): A function that takes path of a file
and check if the file is a valid file. Both :attr:`extensions` and
:attr:`is_valid_file` should not be passed. Default: None.
Returns:
:ref:`api_paddle_io_Dataset`. An instance of DatasetFolder.
Attributes:
classes (list[str]): List of the class names.
class_to_idx (dict[str, int]): Dict with items (class_name, class_index).
samples (list[tuple[str, int]]): List of (sample_path, class_index) tuples.
targets (list[int]): The class_index value for each image in the dataset.
Example:
.. code-block:: pycon
>>> import shutil
>>> import tempfile
>>> import cv2
>>> import numpy as np
>>> import paddle
>>> import paddle.vision.transforms as T
>>> from pathlib import Path
>>> from paddle.vision.datasets import DatasetFolder
>>> def make_fake_file(img_path: str):
... if img_path.endswith((".jpg", ".png", ".jpeg")):
... fake_img = np.random.randint(0, 256, (32, 32, 3), dtype=np.uint8)
... cv2.imwrite(img_path, fake_img)
... elif img_path.endswith(".txt"):
... with open(img_path, "w") as f:
... f.write("This is a fake file.")
>>> def make_directory(root, directory_hierarchy, file_maker=make_fake_file):
... root = Path(root)
... root.mkdir(parents=True, exist_ok=True)
... for subpath in directory_hierarchy:
... if isinstance(subpath, str):
... filepath = root / subpath
... file_maker(str(filepath))
... else:
... dirname = list(subpath.keys())[0]
... make_directory(root / dirname, subpath[dirname])
>>> directory_hierarchy = [
... {"class_0": [
... "abc.jpg",
... "def.png"]},
... {"class_1": [
... "ghi.jpeg",
... "jkl.png",
... {"mno": [
... "pqr.jpeg",
... "stu.jpg"]}]},
... "this_will_be_ignored.txt",
... ] # fmt: skip
>>> # You can replace this with any directory to explore the structure
>>> # of generated data. e.g. fake_data_dir = "./temp_dir"
>>> fake_data_dir = tempfile.mkdtemp()
>>> make_directory(fake_data_dir, directory_hierarchy)
>>> data_folder_1 = DatasetFolder(fake_data_dir)
>>> print(data_folder_1.classes)
['class_0', 'class_1']
>>> print(data_folder_1.class_to_idx)
{'class_0': 0, 'class_1': 1}
>>> print(data_folder_1.samples)
>>> # doctest: +SKIP(it's different with windows)
[('./temp_dir/class_0/abc.jpg', 0), ('./temp_dir/class_0/def.png', 0),
('./temp_dir/class_1/ghi.jpeg', 1), ('./temp_dir/class_1/jkl.png', 1),
('./temp_dir/class_1/mno/pqr.jpeg', 1), ('./temp_dir/class_1/mno/stu.jpg', 1)]
>>> # doctest: -SKIP
>>> print(data_folder_1.targets)
[0, 0, 1, 1, 1, 1]
>>> print(len(data_folder_1))
6
>>> for i in range(len(data_folder_1)):
... img, label = data_folder_1[i]
... # do something with img and label
... print(type(img), img.size, label)
... # <class 'PIL.Image.Image'> (32, 32) 0
>>> transform = T.Compose(
... [
... T.Resize(64),
... T.ToTensor(),
... T.Normalize(
... mean=[0.5, 0.5, 0.5],
... std=[0.5, 0.5, 0.5],
... to_rgb=True,
... ),
... ]
... )
>>> def cv2_loader(path: str):
... image = cv2.imread(path)
... assert image is not None
... return image
>>> data_folder_2 = DatasetFolder(
... fake_data_dir,
... loader=cv2_loader, # load image with OpenCV
... extensions=(".jpg",), # only load *.jpg files
... transform=transform, # apply transform to every image
... )
>>> print([img_path for img_path, label in data_folder_2.samples])
>>> # doctest: +SKIP(it's different with windows)
['./temp_dir/class_0/abc.jpg', './temp_dir/class_1/mno/stu.jpg']
>>> # doctest: -SKIP
>>> print(len(data_folder_2))
2
>>> for img, label in iter(data_folder_2):
... # do something with img and label
... assert isinstance(img, paddle.Tensor)
... print(type(img), img.shape, label)
... # <class 'paddle.Tensor'> [3, 64, 64] 0
>>> shutil.rmtree(fake_data_dir)
"""
loader: Callable[..., _ImageDataType] | None
extensions: Sequence[_AllowedExtensions] | None
transform: _Transform[Any, Any] | None
classes: list[str]
class_to_idx: dict[str, int]
samples: list[tuple[str, int]]
targets: list[str]
dtype: _DTypeLiteral
def __init__(
self,
root: str,
loader: Callable[..., _ImageDataType] | None = None,
extensions: Sequence[_AllowedExtensions] | None = None,
transform: _Transform[Any, Any] | None = None,
is_valid_file: _ImageDataType | None = None,
) -> None:
self.root = root
self.transform = transform
if extensions is None:
extensions = IMG_EXTENSIONS
classes, class_to_idx = self._find_classes(self.root)
samples = make_dataset(
self.root, class_to_idx, extensions, is_valid_file
)
if len(samples) == 0:
raise (
RuntimeError(
"Found 0 directories in subfolders of: " + self.root + "\n"
"Supported extensions are: " + ",".join(extensions)
)
)
self.loader = default_loader if loader is None else loader
self.extensions = extensions
self.classes = classes
self.class_to_idx = class_to_idx
self.samples = samples
self.targets = [s[1] for s in samples]
self.dtype = paddle.get_default_dtype()
def _find_classes(self, dir: str) -> tuple[list[str], dict[str, int]]:
"""
Finds the class folders in a dataset.
Args:
dir (string): Root directory path.
Returns:
tuple: (classes, class_to_idx) where classes are relative to (dir),
and class_to_idx is a dictionary.
"""
classes = [d.name for d in os.scandir(dir) if d.is_dir()]
classes.sort()
class_to_idx = {classes[i]: i for i in range(len(classes))}
return classes, class_to_idx
def __getitem__(self, index: int) -> tuple[_ImageDataType, int]:
"""
Args:
index (int): Index
Returns:
tuple: (sample, target) where target is class_index of the target class.
"""
path, target = self.samples[index]
sample = self.loader(path)
if self.transform is not None:
sample = self.transform(sample)
return sample, target
def __len__(self):
return len(self.samples)
IMG_EXTENSIONS = (
'.jpg',
'.jpeg',
'.png',
'.ppm',
'.bmp',
'.pgm',
'.tif',
'.tiff',
'.webp',
)
def pil_loader(path):
with open(path, 'rb') as f:
img = Image.open(f)
return img.convert('RGB')
def cv2_loader(path):
cv2 = try_import('cv2')
return cv2.cvtColor(cv2.imread(path), cv2.COLOR_BGR2RGB)
def default_loader(path):
from paddle.vision import get_image_backend
if get_image_backend() == 'cv2':
return cv2_loader(path)
else:
return pil_loader(path)
class ImageFolder(Dataset[list["_ImageDataType"]]):
"""A generic data loader where the samples are arranged in this way:
.. code-block:: text
root/1.ext
root/2.ext
root/sub_dir/3.ext
Args:
root (str): Root directory path.
loader (Callable|None, optional): A function to load a sample given its path. Default: None.
extensions (list[str]|tuple[str]|None, optional): A list of allowed extensions.
Both :attr:`extensions` and :attr:`is_valid_file` should not be passed.
If this value is not set, the default is to use ('.jpg', '.jpeg', '.png',
'.ppm', '.bmp', '.pgm', '.tif', '.tiff', '.webp'). Default: None.
transform (Callable|None, optional): A function/transform that takes in
a sample and returns a transformed version. Default: None.
is_valid_file (Callable|None, optional): A function that takes path of a file
and check if the file is a valid file. Both :attr:`extensions` and
:attr:`is_valid_file` should not be passed. Default: None.
Returns:
:ref:`api_paddle_io_Dataset`. An instance of ImageFolder.
Attributes:
samples (list[str]): List of sample path.
Example:
.. code-block:: pycon
>>> import shutil
>>> import tempfile
>>> import cv2
>>> import numpy as np
>>> import paddle
>>> import paddle.vision.transforms as T
>>> from pathlib import Path
>>> from paddle.vision.datasets import ImageFolder
>>> def make_fake_file(img_path: str):
... if img_path.endswith((".jpg", ".png", ".jpeg")):
... fake_img = np.random.randint(0, 256, (32, 32, 3), dtype=np.uint8)
... cv2.imwrite(img_path, fake_img)
... elif img_path.endswith(".txt"):
... with open(img_path, "w") as f:
... f.write("This is a fake file.")
>>> def make_directory(root, directory_hierarchy, file_maker=make_fake_file):
... root = Path(root)
... root.mkdir(parents=True, exist_ok=True)
... for subpath in directory_hierarchy:
... if isinstance(subpath, str):
... filepath = root / subpath
... file_maker(str(filepath))
... else:
... dirname = list(subpath.keys())[0]
... make_directory(root / dirname, subpath[dirname])
>>> directory_hierarchy = [
... "abc.jpg",
... "def.png",
... {"ghi": [
... "jkl.jpeg",
... {"mno": [
... "pqr.jpg"]}]},
... "this_will_be_ignored.txt",
... ] # fmt: skip
>>> # You can replace this with any directory to explore the structure
>>> # of generated data. e.g. fake_data_dir = "./temp_dir"
>>> fake_data_dir = tempfile.mkdtemp()
>>> make_directory(fake_data_dir, directory_hierarchy)
>>> image_folder_1 = ImageFolder(fake_data_dir)
>>> print(image_folder_1.samples)
>>> # doctest: +SKIP(it's different with windows)
['./temp_dir/abc.jpg', './temp_dir/def.png',
'./temp_dir/ghi/jkl.jpeg', './temp_dir/ghi/mno/pqr.jpg']
>>> # doctest: -SKIP
>>> print(len(image_folder_1))
4
>>> for i in range(len(image_folder_1)):
... (img,) = image_folder_1[i]
... # do something with img
... print(type(img), img.size)
... # <class 'PIL.Image.Image'> (32, 32)
>>> transform = T.Compose(
... [
... T.Resize(64),
... T.ToTensor(),
... T.Normalize(
... mean=[0.5, 0.5, 0.5],
... std=[0.5, 0.5, 0.5],
... to_rgb=True,
... ),
... ]
... )
>>> def cv2_loader(path: str):
... image = cv2.imread(path)
... assert image is not None
... return image
>>> image_folder_2 = ImageFolder(
... fake_data_dir,
... loader=cv2_loader, # load image with OpenCV
... extensions=(".jpg",), # only load *.jpg files
... transform=transform, # apply transform to every image
... )
>>> print(image_folder_2.samples)
>>> # doctest: +SKIP(it's different with windows)
['./temp_dir/abc.jpg', './temp_dir/ghi/mno/pqr.jpg']
>>> # doctest: -SKIP
>>> print(len(image_folder_2))
2
>>> for (img,) in iter(image_folder_2):
... # do something with img
... assert isinstance(img, paddle.Tensor)
... print(type(img), img.shape)
... # <class 'paddle.Tensor'> [3, 64, 64]
>>> shutil.rmtree(fake_data_dir)
"""
loader: Callable[..., _ImageDataType] | None
extensions: Sequence[_AllowedExtensions] | None
samples: list[str]
transform: _Transform[Any, Any] | None
def __init__(
self,
root: str,
loader: Callable[..., _ImageDataType] | None = None,
extensions: Sequence[_AllowedExtensions] | None = None,
transform: _Transform[Any, Any] | None = None,
is_valid_file: _ImageDataType | None = None,
) -> None:
self.root = root
if extensions is None:
extensions = IMG_EXTENSIONS
samples = []
path = os.path.expanduser(root)
if extensions is not None:
def is_valid_file(x):
return has_valid_extension(x, extensions)
for root, _, fnames in sorted(os.walk(path, followlinks=True)):
for fname in sorted(fnames):
f = os.path.join(root, fname)
if is_valid_file(f):
samples.append(f)
if len(samples) == 0:
raise (
RuntimeError(
"Found 0 files in subfolders of: " + self.root + "\n"
"Supported extensions are: " + ",".join(extensions)
)
)
self.loader = default_loader if loader is None else loader
self.extensions = extensions
self.samples = samples
self.transform = transform
def __getitem__(self, index: int) -> list[_ImageDataType]:
"""
Args:
index (int): Index
Returns:
sample of specific index.
"""
path = self.samples[index]
sample = self.loader(path)
if self.transform is not None:
sample = self.transform(sample)
return [sample]
def __len__(self) -> int:
return len(self.samples)