# How does one fix an interleaved data set from only sampling one data set?

**URL:** <https://discuss.huggingface.co/t/how-does-one-fix-an-interleaved-data-set-from-only-sampling-one-data-set/50041>\
**Category:** Beginners\
**Created:** [August 9, 2023, 12:43am UTC](https://discuss.huggingface.co/t/how-does-one-fix-an-interleaved-data-set-from-only-sampling-one-data-set/50041 "2023-08-09T00:43:03Z")\
**Posts on this page:** 2\
**Page:** 1

<div class="post-metadata">

**Author:** ![brando](https://sea2.discourse-cdn.com/hellohellohello/user_avatar/discuss.huggingface.co/brando/32/30114_2.png) [@brando](https://discuss.huggingface.co/u/brando)\
**Post date:** [August 9, 2023, 12:43am UTC](https://discuss.huggingface.co/t/how-does-one-fix-an-interleaved-data-set-from-only-sampling-one-data-set/50041/1 "2023-08-09T00:43:04Z")

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The following

```auto
from datasets import load_dataset
from datasets import interleave_datasets

# Preprocess each dataset
c4 = load_dataset("c4", "en", split="train", streaming=True) 
wikitext = load_dataset("wikitext", "wikitext-103-v1", split="train", streaming=True)

# Interleave the preprocessed datasets  
datasets = [c4, wikitext]
for dataset in datasets:
  print(dataset.description)
interleaved = interleave_datasets(datasets, probabilities=[0.5, 0.5])
print(interleaved)

```

only samples from one data set, why?

```auto
example.keys()=dict_keys(['text', 'timestamp', 'url'])
example.keys()=dict_keys(['text', 'timestamp', 'url'])
example.keys()=dict_keys(['text', 'timestamp', 'url'])
example.keys()=dict_keys(['text', 'timestamp', 'url'])
example.keys()=dict_keys(['text', 'timestamp', 'url'])
example.keys()=dict_keys(['text', 'timestamp', 'url'])
example.keys()=dict_keys(['text', 'timestamp', 'url'])
example.keys()=dict_keys(['text', 'timestamp', 'url'])
example.keys()=dict_keys(['text', 'timestamp', 'url'])
example.keys()=dict_keys(['text', 'timestamp', 'url'])
example.keys()=dict_keys(['text', 'timestamp', 'url'])
example.keys()=dict_keys(['text', 'timestamp', 'url'])
example.keys()=dict_keys(['text', 'timestamp', 'url'])
example.keys()=dict_keys(['text', 'timestamp', 'url'])
example.keys()=dict_keys(['text', 'timestamp', 'url'])
example.keys()=dict_keys(['text', 'timestamp', 'url'])
example.keys()=dict_keys(['text', 'timestamp', 'url'])
example.keys()=dict_keys(['text', 'timestamp', 'url'])
example.keys()=dict_keys(['text', 'timestamp', 'url'])
example.keys()=dict_keys(['text', 'timestamp', 'url'])
example.keys()=dict_keys(['text', 'timestamp', 'url'])
example.keys()=dict_keys(['text', 'timestamp', 'url'])
counts=100

```

colab: [Google Colab](https://colab.research.google.com/drive/1VIR66U1d7qk3Q1vU_URoo5tHEEheORpN?usp=sharing)  
hf dicord: [Discord](https://discord.com/channels/879548962464493619/1138632039197835354)

> <https://stackoverflow.com/questions/76863889/how-does-one-fix-an-interleaved-data-set-from-only-sampling-one-data-set>

---

<div class="post-metadata">

**Author:** ![mariosasko](https://sea2.discourse-cdn.com/hellohellohello/user_avatar/discuss.huggingface.co/mariosasko/32/31548_2.png) [@mariosasko](https://discuss.huggingface.co/u/mariosasko)\
**Post date:** [August 14, 2023, 1:05pm UTC](https://discuss.huggingface.co/t/how-does-one-fix-an-interleaved-data-set-from-only-sampling-one-data-set/50041/2 "2023-08-14T13:05:47Z")

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These datasets’ features don’t match, so `interleave_datasets` / `concatenate_datasets` generates their union and adds them as `None` where needed (`timestamp` and `url` are `None` in the `wikitext` samples), hence the same set of keys in the output.