# Cannot display examples from IterableDataset

**URL:** <https://discuss.huggingface.co/t/cannot-display-examples-from-iterabledataset/63434>\
**Category:** 🤗Datasets\
**Created:** [November 24, 2023, 5:47pm UTC](https://discuss.huggingface.co/t/cannot-display-examples-from-iterabledataset/63434 "2023-11-24T17:47:32Z")\
**Posts on this page:** 3\
**Page:** 1

<div class="post-metadata">

**Author:** ![ombrr](https://sea2.discourse-cdn.com/hellohellohello/user_avatar/discuss.huggingface.co/ombrr/32/43098_2.png) [@ombrr](https://discuss.huggingface.co/u/ombrr)\
**Post date:** [November 24, 2023, 5:47pm UTC](https://discuss.huggingface.co/t/cannot-display-examples-from-iterabledataset/63434/1 "2023-11-24T17:47:32Z")

</div>

Hello everyone!

I am working with a **large dataset of images** which I am loading in **Streaming mode** to save disk space. Doing so, I end up with an IterableDataset.  
Following [this tutorial](https://huggingface.co/blog/fine-tune-vit), I would like to display a grid of examples from each class, just to have a few data visual examples.

You can find all the code in the tutorial linked above, but this is the part of code I am interested in and I am having trouble with:

```auto
import random
from PIL import ImageDraw, ImageFont, Image

def show_examples(ds, seed: int = 1234, examples_per_class: int = 3, size=(350, 350)):

    w, h = size
    labels = ds['train'].features['labels'].names
    grid = Image.new('RGB', size=(examples_per_class * w, len(labels) * h))
    draw = ImageDraw.Draw(grid)
    font = ImageFont.load_default() 

    for label_id, label in enumerate(labels):

        # Filter the dataset by a single label, shuffle it, and grab a few samples
        ds_slice = ds['train'].filter(lambda ex: ex['labels'] == label_id).shuffle(seed).select(range(examples_per_class))

        # Plot this label's examples along a row
        for i, example in enumerate(ds_slice):
            image = example['image']
            idx = examples_per_class * label_id + i
            box = (idx % examples_per_class * w, idx // examples_per_class * h)
            grid.paste(image.resize(size), box=box)
            draw.text(box, label, (255, 255, 255), font=font)

    return grid

show_examples(ds, seed=random.randint(0, 1337), examples_per_class=3)

```

I changed the slice part to:

```auto
ds_slice = ds.take(9)

```

But using `take()` does not guarantee the presence of n samples from each class.

In short, my problem is that **I cannot filter an IterableDataset by a single label** and grab just a few examples for each label/class. Is there a way to do this or should I just give up?

Unfortunately I cannot provide my dataset for copyright reasons, but if you need more details I can explain more.

Thank you in advance!

---

<div class="post-metadata">

**Author:** ![lhoestq](https://sea2.discourse-cdn.com/hellohellohello/user_avatar/discuss.huggingface.co/lhoestq/32/52888_2.png) [@lhoestq](https://discuss.huggingface.co/u/lhoestq)\
**Post date:** [November 27, 2023, 11:37am UTC](https://discuss.huggingface.co/t/cannot-display-examples-from-iterabledataset/63434/2 "2023-11-27T11:37:54Z")

</div>

First, make sure you keep keep the `.filter(...)` operation, then you can apply `take`

```python
ds_slice = ds['train'].filter(lambda ex: ex['labels'] == label_id).take(examples_per_class)

```

and if you end up with less than `examples_per_class` it means that the filter scanned the full dataset and couldn’t find `examples_per_class` examples for a certain class.

---

<div class="post-metadata">

**Author:** ![ombrr](https://sea2.discourse-cdn.com/hellohellohello/user_avatar/discuss.huggingface.co/ombrr/32/43098_2.png) [@ombrr](https://discuss.huggingface.co/u/ombrr)\
**Post date:** [November 27, 2023, 2:56pm UTC](https://discuss.huggingface.co/t/cannot-display-examples-from-iterabledataset/63434/3 "2023-11-27T14:56:03Z")

</div>

Thank you so much, it worked! 🙂

Reference for possible future users, I have a 24GB image dataset (IterableDataset object, very unbalanced with respect to the three different classes) and running the above code (with the edit by @lhoestq) took about 20 minutes with `examples_per_class=1`… so maybe not the fastest way to see image examples.

I am satisfied for now, will update this post in case I manage to improve speed.  
Thanks again and have a nice day!