add README.md

README.md

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+---
+annotations_creators:
+- expert-generated
+language_creators:
+- other
+languages:
+- pl
+licenses:
+- gpl-3.0
+multilinguality:
+- monolingual
+pretty_name: 'nkjp-pos'
+size_categories:
+- unknown
+source_datasets:
+- original
+task_categories:
+- structure-prediction
+task_ids:
+- part-of-speech-tagging
+---
+
+# nkjp-pos
+
+## Description
+
+NKJP-POS is a part the National Corpus of Polish (*Narodowy Korpus Języka Polskiego*). Its objective is part-of-speech tagging, e.g. nouns, verbs, adjectives, adverbs, etc. During the creation of corpus, texts of were annotated by humans from various sources, covering many domains and genres.
+
+## Tasks (input, output and metrics)
+
+Part-of-speech tagging (POS tagging) - tagging words in text with their corresponding part of speech.
+
+**Input** ('*tokens'* column): sequence of tokens
+
+**Output** ('*pos_tags'* column): sequence of predicted tokens’ classes (35 possible classes, described in detail in the annotation guidelines)
+
+***example**:*
+
+[*'Zarejestruj', 'się', 'jako', 'bezrobotny', '.'*] → [*'impt', 'qub', 'conj', 'subst', 'interp'*]
+
+Measurements:
+
+## Data splits
+
+| Subset      | Cardinality (sentences) |
+| ----------- | ----------------------: |
+| train       | 68528                   |
+| val         | 8566                    |
+| test        | 8566                    |
+
+
+## Class distribution in train
+
+
+| Class   |   Fraction of tokens |
+|:--------|---------------------:|
+| subst   |              0.27295 |
+| interp  |              0.18381 |
+| adj     |              0.10607 |
+| prep    |              0.09533 |
+| qub     |              0.05633 |
+| fin     |              0.04895 |
+| praet   |              0.04385 |
+| conj    |              0.03685 |
+| adv     |              0.03498 |
+| inf     |              0.01586 |
+| comp    |              0.01465 |
+| num     |              0.01319 |
+| ppron3  |              0.01090 |
+| ppas    |              0.01080 |
+| ger     |              0.00967 |
+| brev    |              0.00880 |
+| ppron12 |              0.00668 |
+| aglt    |              0.00620 |
+| pred    |              0.00536 |
+| pact    |              0.00452 |
+| bedzie  |              0.00232 |
+| pcon    |              0.00216 |
+| impt    |              0.00201 |
+| siebie  |              0.00175 |
+| imps    |              0.00172 |
+| interj  |              0.00128 |
+| xxx     |              0.00067 |
+| winien  |              0.00066 |
+| adjp    |              0.00066 |
+| adja    |              0.00048 |
+| pant    |              0.00013 |
+| depr    |              0.00010 |
+| burk    |              0.00010 |
+| numcol  |              0.00010 |
+| adjc    |              0.00007 |
+
+
+## Citation
+
+```
+@book{przepiorkowski_narodowy_2012,
+title = {Narodowy korpus języka polskiego},
+isbn = {978-83-01-16700-4},
+language = {pl},
+publisher = {Wydawnictwo Naukowe PWN},
+editor = {Przepiórkowski, Adam and Bańko, Mirosław and Górski, Rafał L. and Lewandowska-Tomaszczyk, Barbara},
+year = {2012}
+}
+```
+
+## License
+
+```
+GNU GPL v.3
+```
+
+## Links
+
+[HuggingFace](https://huggingface.co/datasets/clarin-pl/nkjp-pos)
+
+[Source](http://clip.ipipan.waw.pl/NationalCorpusOfPolish)
+
+[Paper](http://nkjp.pl/settings/papers/NKJP_ksiazka.pdf)
+
+## Examples
+
+### Loading
+
+```python
+from pprint import pprint
+
+from datasets import load_dataset
+
+dataset = load_dataset("clarin-pl/nkjp-pos")
+pprint(dataset['train'][5000])
+
+# {'full_pos_tags': ['fin:sg:ter:imperf',
+#                    'subst:sg:nom:f',
+#                    'adj:sg:nom:f:pos',
+#                    'interp'],
+#  'lemmas': ['trwać', 'akcja', 'poszukiwawczy', '.'],
+#  'morph': ['trwać|fin:sg:ter:imperf',
+#            'akcja|subst:sg:nom:f',
+#            'poszukiwawczy|adj:sg:nom:f:pos poszukiwawczy|adj:sg:voc:f:pos',
+#            '.|interp'],
+#  'nps': ['', '', 'nps', ''],
+#  'pos_tags': [12, 32, 0, 18],
+#  'tokens': ['Trwa', 'akcja', 'poszukiwawcza', '.']}
+```
+
+### Evaluation
+
+```python
+import random
+from pprint import pprint
+
+from datasets import load_dataset, load_metric
+
+dataset = load_dataset("clarin-pl/nkjp-pos")
+references = dataset["test"]["pos_tags"]
+
+# generate random predictions
+predictions = [
+    [
+        random.randrange(dataset["train"].features["pos_tags"].feature.num_classes)
+        for _ in range(len(labels))
+    ]
+    for labels in references
+]
+
+# transform to original names of labels
+references_named = [
+    [dataset["train"].features["pos_tags"].feature.names[label] for label in labels]
+    for labels in references
+]
+predictions_named = [
+    [dataset["train"].features["pos_tags"].feature.names[label] for label in labels]
+    for labels in predictions
+]
+
+# transform to BILOU scheme
+references_named = [
+    [f"U-{label}" if label != "O" else label for label in labels]
+    for labels in references_named
+]
+predictions_named = [
+    [f"U-{label}" if label != "O" else label for label in labels]
+    for labels in predictions_named
+]
+
+# utilise seqeval to evaluate
+seqeval = load_metric("seqeval")
+seqeval_score = seqeval.compute(
+    predictions=predictions_named,
+    references=references_named,
+    scheme="BILOU",
+    mode="strict",
+)
+
+pprint(seqeval_score, depth=1)
+
+# {'adj': {...},
+#  'adja': {...},
+#  'adjc': {...},
+#  'adjp': {...},
+#  'adv': {...},
+#  'aglt': {...},
+#  'bedzie': {...},
+#  'brev': {...},
+#  'burk': {...},
+#  'comp': {...},
+#  'conj': {...},
+#  'depr': {...},
+#  'fin': {...},
+#  'ger': {...},
+#  'imps': {...},
+#  'impt': {...},
+#  'inf': {...},
+#  'interj': {...},
+#  'interp': {...},
+#  'num': {...},
+#  'numcol': {...},
+#  'overall_accuracy': 0.027855061488566583,
+#  'overall_f1': 0.027855061488566583,
+#  'overall_precision': 0.027855061488566583,
+#  'overall_recall': 0.027855061488566583,
+#  'pact': {...},
+#  'pant': {...},
+#  'pcon': {...},
+#  'ppas': {...},
+#  'ppron12': {...},
+#  'ppron3': {...},
+#  'praet': {...},
+#  'pred': {...},
+#  'prep': {...},
+#  'qub': {...},
+#  'siebie': {...},
+#  'subst': {...},
+#  'winien': {...},
+#  'xxx': {...}}
+```