Why is dataset after tokenization far more larger than the orginal one ?
Thanks for your point. 😀, It might be answer.
Since this is hard to know, I'll close this issue.
But if somebody knows more details, please comment below ~ 😁
I tokenize wiki dataset by `map` and cache the results.
```
def tokenize_tfm(example):
    example['input_ids'] = hf_fast_tokenizer.convert_tokens_to_ids(hf_fast_tokenizer.tokenize(example['text']))
    return example
wiki = nlp.load_dataset('wikipedia', '20200501.en', cache_dir=cache_dir)['train']
wiki.map(tokenize_tfm, cache_file_name=cache_dir/"wikipedia/20200501.en/1.0.0/tokenized_wiki.arrow")
```
and when I see their size
```
ls -l --block-size=M
17460M  wikipedia-train.arrow
47511M  tokenized_wiki.arrow
```
The tokenized one is over 2x size of original one.
Is there something I did wrong ?
Why is dataset after tokenization far more larger than the orginal one ? 
 I tokenize wiki dataset by `map` and cache the results.
```
def tokenize_tfm(example):
    example['input_ids'] = hf_fast_tokenizer.convert_tokens_to_ids(hf_fast_tokenizer.tokenize(example['text']))
    return example
wiki = nlp.load_dataset('wikipedia', '20200501.en', cache_dir=cache_dir)['train']
wiki.map(tokenize_tfm, cache_file_name=cache_dir/"wikipedia/20200501.en/1.0.0/tokenized_wiki.arrow")
```
and when I see their size
```
ls -l --block-size=M
17460M  wikipedia-train.arrow
47511M  tokenized_wiki.arrow
```
The tokenized one is over 2x size of original one.
Is there something I did wrong ? 
 Thanks for your point. 😀, It might be answer.
Since this is hard to know, I'll close this issue.
But if somebody knows more details, please comment below ~ 😁