1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
|
%global _empty_manifest_terminate_build 0
Name: python-keybert
Version: 0.7.0
Release: 1
Summary: KeyBERT performs keyword extraction with state-of-the-art transformer models.
License: MIT License
URL: https://github.com/MaartenGr/keyBERT
Source0: https://mirrors.nju.edu.cn/pypi/web/packages/9a/41/b7b21fb0abee8381b83db942fd6dc31c9d61d59a6af0f0f78e310a5cf908/keybert-0.7.0.tar.gz
BuildArch: noarch
%description
[](https://pypi.org/project/keybert/)
[](https://github.com/MaartenGr/keybert/blob/master/LICENSE)
[](https://pypi.org/project/keybert/)
[](https://pypi.org/project/keybert/)
[](https://colab.research.google.com/drive/1OxpgwKqSzODtO3vS7Xe1nEmZMCAIMckX?usp=sharing)
<img src="images/logo.png" width="35%" height="35%" align="right" />
# KeyBERT
KeyBERT is a minimal and easy-to-use keyword extraction technique that leverages BERT embeddings to
create keywords and keyphrases that are most similar to a document.
Corresponding medium post can be found [here](https://towardsdatascience.com/keyword-extraction-with-bert-724efca412ea).
<a name="toc"/></a>
## Table of Contents
<!--ts-->
1. [About the Project](#about)
2. [Getting Started](#gettingstarted)
2.1. [Installation](#installation)
2.2. [Basic Usage](#usage)
2.3. [Max Sum Distance](#maxsum)
2.4. [Maximal Marginal Relevance](#maximal)
2.5. [Embedding Models](#embeddings)
<!--te-->
<a name="about"/></a>
## 1. About the Project
[Back to ToC](#toc)
Although there are already many methods available for keyword generation
(e.g.,
[Rake](https://github.com/aneesha/RAKE),
[YAKE!](https://github.com/LIAAD/yake), TF-IDF, etc.)
I wanted to create a very basic, but powerful method for extracting keywords and keyphrases.
This is where **KeyBERT** comes in! Which uses BERT-embeddings and simple cosine similarity
to find the sub-phrases in a document that are the most similar to the document itself.
First, document embeddings are extracted with BERT to get a document-level representation.
Then, word embeddings are extracted for N-gram words/phrases. Finally, we use cosine similarity
to find the words/phrases that are the most similar to the document. The most similar words could
then be identified as the words that best describe the entire document.
KeyBERT is by no means unique and is created as a quick and easy method
for creating keywords and keyphrases. Although there are many great
papers and solutions out there that use BERT-embeddings
(e.g.,
[1](https://github.com/pranav-ust/BERT-keyphrase-extraction),
[2](https://github.com/ibatra/BERT-Keyword-Extractor),
[3](https://www.preprints.org/manuscript/201908.0073/download/final_file),
), I could not find a BERT-based solution that did not have to be trained from scratch and
could be used for beginners (**correct me if I'm wrong!**).
Thus, the goal was a `pip install keybert` and at most 3 lines of code in usage.
<a name="gettingstarted"/></a>
## 2. Getting Started
[Back to ToC](#toc)
<a name="installation"/></a>
### 2.1. Installation
Installation can be done using [pypi](https://pypi.org/project/keybert/):
```
pip install keybert
```
You may want to install more depending on the transformers and language backends that you will be using. The possible installations are:
```
pip install keybert[flair]
pip install keybert[gensim]
pip install keybert[spacy]
pip install keybert[use]
```
<a name="usage"/></a>
### 2.2. Usage
The most minimal example can be seen below for the extraction of keywords:
```python
from keybert import KeyBERT
doc = """
Supervised learning is the machine learning task of learning a function that
maps an input to an output based on example input-output pairs. It infers a
function from labeled training data consisting of a set of training examples.
In supervised learning, each example is a pair consisting of an input object
(typically a vector) and a desired output value (also called the supervisory signal).
A supervised learning algorithm analyzes the training data and produces an inferred function,
which can be used for mapping new examples. An optimal scenario will allow for the
algorithm to correctly determine the class labels for unseen instances. This requires
the learning algorithm to generalize from the training data to unseen situations in a
'reasonable' way (see inductive bias).
"""
kw_model = KeyBERT()
keywords = kw_model.extract_keywords(doc)
```
You can set `keyphrase_ngram_range` to set the length of the resulting keywords/keyphrases:
```python
>>> kw_model.extract_keywords(doc, keyphrase_ngram_range=(1, 1), stop_words=None)
[('learning', 0.4604),
('algorithm', 0.4556),
('training', 0.4487),
('class', 0.4086),
('mapping', 0.3700)]
```
To extract keyphrases, simply set `keyphrase_ngram_range` to (1, 2) or higher depending on the number
of words you would like in the resulting keyphrases:
```python
>>> kw_model.extract_keywords(doc, keyphrase_ngram_range=(1, 2), stop_words=None)
[('learning algorithm', 0.6978),
('machine learning', 0.6305),
('supervised learning', 0.5985),
('algorithm analyzes', 0.5860),
('learning function', 0.5850)]
```
We can highlight the keywords in the document by simply setting `highlight`:
```python
keywords = kw_model.extract_keywords(doc, highlight=True)
```
<img src="images/highlight.png" width="75%" height="75%" />
**NOTE**: For a full overview of all possible transformer models see [sentence-transformer](https://www.sbert.net/docs/pretrained_models.html).
I would advise either `"all-MiniLM-L6-v2"` for English documents or `"paraphrase-multilingual-MiniLM-L12-v2"`
for multi-lingual documents or any other language.
<a name="maxsum"/></a>
### 2.3. Max Sum Distance
To diversify the results, we take the 2 x top_n most similar words/phrases to the document.
Then, we take all top_n combinations from the 2 x top_n words and extract the combination
that are the least similar to each other by cosine similarity.
```python
>>> kw_model.extract_keywords(doc, keyphrase_ngram_range=(3, 3), stop_words='english',
use_maxsum=True, nr_candidates=20, top_n=5)
[('set training examples', 0.7504),
('generalize training data', 0.7727),
('requires learning algorithm', 0.5050),
('supervised learning algorithm', 0.3779),
('learning machine learning', 0.2891)]
```
<a name="maximal"/></a>
### 2.4. Maximal Marginal Relevance
To diversify the results, we can use Maximal Margin Relevance (MMR) to create
keywords / keyphrases which is also based on cosine similarity. The results
with **high diversity**:
```python
>>> kw_model.extract_keywords(doc, keyphrase_ngram_range=(3, 3), stop_words='english',
use_mmr=True, diversity=0.7)
[('algorithm generalize training', 0.7727),
('labels unseen instances', 0.1649),
('new examples optimal', 0.4185),
('determine class labels', 0.4774),
('supervised learning algorithm', 0.7502)]
```
The results with **low diversity**:
```python
>>> kw_model.extract_keywords(doc, keyphrase_ngram_range=(3, 3), stop_words='english',
use_mmr=True, diversity=0.2)
[('algorithm generalize training', 0.7727),
('supervised learning algorithm', 0.7502),
('learning machine learning', 0.7577),
('learning algorithm analyzes', 0.7587),
('learning algorithm generalize', 0.7514)]
```
<a name="embeddings"/></a>
### 2.5. Embedding Models
KeyBERT supports many embedding models that can be used to embed the documents and words:
* Sentence-Transformers
* Flair
* Spacy
* Gensim
* USE
Click [here](https://maartengr.github.io/KeyBERT/guides/embeddings.html) for a full overview of all supported embedding models.
**Sentence-Transformers**
You can select any model from `sentence-transformers` [here](https://www.sbert.net/docs/pretrained_models.html)
and pass it through KeyBERT with `model`:
```python
from keybert import KeyBERT
kw_model = KeyBERT(model='all-MiniLM-L6-v2')
```
Or select a SentenceTransformer model with your own parameters:
```python
from keybert import KeyBERT
from sentence_transformers import SentenceTransformer
sentence_model = SentenceTransformer("all-MiniLM-L6-v2")
kw_model = KeyBERT(model=sentence_model)
```
**Flair**
[Flair](https://github.com/flairNLP/flair) allows you to choose almost any embedding model that
is publicly available. Flair can be used as follows:
```python
from keybert import KeyBERT
from flair.embeddings import TransformerDocumentEmbeddings
roberta = TransformerDocumentEmbeddings('roberta-base')
kw_model = KeyBERT(model=roberta)
```
You can select any 🤗 transformers model [here](https://huggingface.co/models).
## Citation
To cite KeyBERT in your work, please use the following bibtex reference:
```bibtex
@misc{grootendorst2020keybert,
author = {Maarten Grootendorst},
title = {KeyBERT: Minimal keyword extraction with BERT.},
year = 2020,
publisher = {Zenodo},
version = {v0.3.0},
doi = {10.5281/zenodo.4461265},
url = {https://doi.org/10.5281/zenodo.4461265}
}
```
## References
Below, you can find several resources that were used for the creation of KeyBERT
but most importantly, these are amazing resources for creating impressive keyword extraction models:
**Papers**:
* Sharma, P., & Li, Y. (2019). [Self-Supervised Contextual Keyword and Keyphrase Retrieval with Self-Labelling.](https://www.preprints.org/manuscript/201908.0073/download/final_file)
**Github Repos**:
* https://github.com/thunlp/BERT-KPE
* https://github.com/ibatra/BERT-Keyword-Extractor
* https://github.com/pranav-ust/BERT-keyphrase-extraction
* https://github.com/swisscom/ai-research-keyphrase-extraction
**MMR**:
The selection of keywords/keyphrases was modeled after:
* https://github.com/swisscom/ai-research-keyphrase-extraction
**NOTE**: If you find a paper or github repo that has an easy-to-use implementation
of BERT-embeddings for keyword/keyphrase extraction, let me know! I'll make sure to
add a reference to this repo.
%package -n python3-keybert
Summary: KeyBERT performs keyword extraction with state-of-the-art transformer models.
Provides: python-keybert
BuildRequires: python3-devel
BuildRequires: python3-setuptools
BuildRequires: python3-pip
%description -n python3-keybert
[](https://pypi.org/project/keybert/)
[](https://github.com/MaartenGr/keybert/blob/master/LICENSE)
[](https://pypi.org/project/keybert/)
[](https://pypi.org/project/keybert/)
[](https://colab.research.google.com/drive/1OxpgwKqSzODtO3vS7Xe1nEmZMCAIMckX?usp=sharing)
<img src="images/logo.png" width="35%" height="35%" align="right" />
# KeyBERT
KeyBERT is a minimal and easy-to-use keyword extraction technique that leverages BERT embeddings to
create keywords and keyphrases that are most similar to a document.
Corresponding medium post can be found [here](https://towardsdatascience.com/keyword-extraction-with-bert-724efca412ea).
<a name="toc"/></a>
## Table of Contents
<!--ts-->
1. [About the Project](#about)
2. [Getting Started](#gettingstarted)
2.1. [Installation](#installation)
2.2. [Basic Usage](#usage)
2.3. [Max Sum Distance](#maxsum)
2.4. [Maximal Marginal Relevance](#maximal)
2.5. [Embedding Models](#embeddings)
<!--te-->
<a name="about"/></a>
## 1. About the Project
[Back to ToC](#toc)
Although there are already many methods available for keyword generation
(e.g.,
[Rake](https://github.com/aneesha/RAKE),
[YAKE!](https://github.com/LIAAD/yake), TF-IDF, etc.)
I wanted to create a very basic, but powerful method for extracting keywords and keyphrases.
This is where **KeyBERT** comes in! Which uses BERT-embeddings and simple cosine similarity
to find the sub-phrases in a document that are the most similar to the document itself.
First, document embeddings are extracted with BERT to get a document-level representation.
Then, word embeddings are extracted for N-gram words/phrases. Finally, we use cosine similarity
to find the words/phrases that are the most similar to the document. The most similar words could
then be identified as the words that best describe the entire document.
KeyBERT is by no means unique and is created as a quick and easy method
for creating keywords and keyphrases. Although there are many great
papers and solutions out there that use BERT-embeddings
(e.g.,
[1](https://github.com/pranav-ust/BERT-keyphrase-extraction),
[2](https://github.com/ibatra/BERT-Keyword-Extractor),
[3](https://www.preprints.org/manuscript/201908.0073/download/final_file),
), I could not find a BERT-based solution that did not have to be trained from scratch and
could be used for beginners (**correct me if I'm wrong!**).
Thus, the goal was a `pip install keybert` and at most 3 lines of code in usage.
<a name="gettingstarted"/></a>
## 2. Getting Started
[Back to ToC](#toc)
<a name="installation"/></a>
### 2.1. Installation
Installation can be done using [pypi](https://pypi.org/project/keybert/):
```
pip install keybert
```
You may want to install more depending on the transformers and language backends that you will be using. The possible installations are:
```
pip install keybert[flair]
pip install keybert[gensim]
pip install keybert[spacy]
pip install keybert[use]
```
<a name="usage"/></a>
### 2.2. Usage
The most minimal example can be seen below for the extraction of keywords:
```python
from keybert import KeyBERT
doc = """
Supervised learning is the machine learning task of learning a function that
maps an input to an output based on example input-output pairs. It infers a
function from labeled training data consisting of a set of training examples.
In supervised learning, each example is a pair consisting of an input object
(typically a vector) and a desired output value (also called the supervisory signal).
A supervised learning algorithm analyzes the training data and produces an inferred function,
which can be used for mapping new examples. An optimal scenario will allow for the
algorithm to correctly determine the class labels for unseen instances. This requires
the learning algorithm to generalize from the training data to unseen situations in a
'reasonable' way (see inductive bias).
"""
kw_model = KeyBERT()
keywords = kw_model.extract_keywords(doc)
```
You can set `keyphrase_ngram_range` to set the length of the resulting keywords/keyphrases:
```python
>>> kw_model.extract_keywords(doc, keyphrase_ngram_range=(1, 1), stop_words=None)
[('learning', 0.4604),
('algorithm', 0.4556),
('training', 0.4487),
('class', 0.4086),
('mapping', 0.3700)]
```
To extract keyphrases, simply set `keyphrase_ngram_range` to (1, 2) or higher depending on the number
of words you would like in the resulting keyphrases:
```python
>>> kw_model.extract_keywords(doc, keyphrase_ngram_range=(1, 2), stop_words=None)
[('learning algorithm', 0.6978),
('machine learning', 0.6305),
('supervised learning', 0.5985),
('algorithm analyzes', 0.5860),
('learning function', 0.5850)]
```
We can highlight the keywords in the document by simply setting `highlight`:
```python
keywords = kw_model.extract_keywords(doc, highlight=True)
```
<img src="images/highlight.png" width="75%" height="75%" />
**NOTE**: For a full overview of all possible transformer models see [sentence-transformer](https://www.sbert.net/docs/pretrained_models.html).
I would advise either `"all-MiniLM-L6-v2"` for English documents or `"paraphrase-multilingual-MiniLM-L12-v2"`
for multi-lingual documents or any other language.
<a name="maxsum"/></a>
### 2.3. Max Sum Distance
To diversify the results, we take the 2 x top_n most similar words/phrases to the document.
Then, we take all top_n combinations from the 2 x top_n words and extract the combination
that are the least similar to each other by cosine similarity.
```python
>>> kw_model.extract_keywords(doc, keyphrase_ngram_range=(3, 3), stop_words='english',
use_maxsum=True, nr_candidates=20, top_n=5)
[('set training examples', 0.7504),
('generalize training data', 0.7727),
('requires learning algorithm', 0.5050),
('supervised learning algorithm', 0.3779),
('learning machine learning', 0.2891)]
```
<a name="maximal"/></a>
### 2.4. Maximal Marginal Relevance
To diversify the results, we can use Maximal Margin Relevance (MMR) to create
keywords / keyphrases which is also based on cosine similarity. The results
with **high diversity**:
```python
>>> kw_model.extract_keywords(doc, keyphrase_ngram_range=(3, 3), stop_words='english',
use_mmr=True, diversity=0.7)
[('algorithm generalize training', 0.7727),
('labels unseen instances', 0.1649),
('new examples optimal', 0.4185),
('determine class labels', 0.4774),
('supervised learning algorithm', 0.7502)]
```
The results with **low diversity**:
```python
>>> kw_model.extract_keywords(doc, keyphrase_ngram_range=(3, 3), stop_words='english',
use_mmr=True, diversity=0.2)
[('algorithm generalize training', 0.7727),
('supervised learning algorithm', 0.7502),
('learning machine learning', 0.7577),
('learning algorithm analyzes', 0.7587),
('learning algorithm generalize', 0.7514)]
```
<a name="embeddings"/></a>
### 2.5. Embedding Models
KeyBERT supports many embedding models that can be used to embed the documents and words:
* Sentence-Transformers
* Flair
* Spacy
* Gensim
* USE
Click [here](https://maartengr.github.io/KeyBERT/guides/embeddings.html) for a full overview of all supported embedding models.
**Sentence-Transformers**
You can select any model from `sentence-transformers` [here](https://www.sbert.net/docs/pretrained_models.html)
and pass it through KeyBERT with `model`:
```python
from keybert import KeyBERT
kw_model = KeyBERT(model='all-MiniLM-L6-v2')
```
Or select a SentenceTransformer model with your own parameters:
```python
from keybert import KeyBERT
from sentence_transformers import SentenceTransformer
sentence_model = SentenceTransformer("all-MiniLM-L6-v2")
kw_model = KeyBERT(model=sentence_model)
```
**Flair**
[Flair](https://github.com/flairNLP/flair) allows you to choose almost any embedding model that
is publicly available. Flair can be used as follows:
```python
from keybert import KeyBERT
from flair.embeddings import TransformerDocumentEmbeddings
roberta = TransformerDocumentEmbeddings('roberta-base')
kw_model = KeyBERT(model=roberta)
```
You can select any 🤗 transformers model [here](https://huggingface.co/models).
## Citation
To cite KeyBERT in your work, please use the following bibtex reference:
```bibtex
@misc{grootendorst2020keybert,
author = {Maarten Grootendorst},
title = {KeyBERT: Minimal keyword extraction with BERT.},
year = 2020,
publisher = {Zenodo},
version = {v0.3.0},
doi = {10.5281/zenodo.4461265},
url = {https://doi.org/10.5281/zenodo.4461265}
}
```
## References
Below, you can find several resources that were used for the creation of KeyBERT
but most importantly, these are amazing resources for creating impressive keyword extraction models:
**Papers**:
* Sharma, P., & Li, Y. (2019). [Self-Supervised Contextual Keyword and Keyphrase Retrieval with Self-Labelling.](https://www.preprints.org/manuscript/201908.0073/download/final_file)
**Github Repos**:
* https://github.com/thunlp/BERT-KPE
* https://github.com/ibatra/BERT-Keyword-Extractor
* https://github.com/pranav-ust/BERT-keyphrase-extraction
* https://github.com/swisscom/ai-research-keyphrase-extraction
**MMR**:
The selection of keywords/keyphrases was modeled after:
* https://github.com/swisscom/ai-research-keyphrase-extraction
**NOTE**: If you find a paper or github repo that has an easy-to-use implementation
of BERT-embeddings for keyword/keyphrase extraction, let me know! I'll make sure to
add a reference to this repo.
%package help
Summary: Development documents and examples for keybert
Provides: python3-keybert-doc
%description help
[](https://pypi.org/project/keybert/)
[](https://github.com/MaartenGr/keybert/blob/master/LICENSE)
[](https://pypi.org/project/keybert/)
[](https://pypi.org/project/keybert/)
[](https://colab.research.google.com/drive/1OxpgwKqSzODtO3vS7Xe1nEmZMCAIMckX?usp=sharing)
<img src="images/logo.png" width="35%" height="35%" align="right" />
# KeyBERT
KeyBERT is a minimal and easy-to-use keyword extraction technique that leverages BERT embeddings to
create keywords and keyphrases that are most similar to a document.
Corresponding medium post can be found [here](https://towardsdatascience.com/keyword-extraction-with-bert-724efca412ea).
<a name="toc"/></a>
## Table of Contents
<!--ts-->
1. [About the Project](#about)
2. [Getting Started](#gettingstarted)
2.1. [Installation](#installation)
2.2. [Basic Usage](#usage)
2.3. [Max Sum Distance](#maxsum)
2.4. [Maximal Marginal Relevance](#maximal)
2.5. [Embedding Models](#embeddings)
<!--te-->
<a name="about"/></a>
## 1. About the Project
[Back to ToC](#toc)
Although there are already many methods available for keyword generation
(e.g.,
[Rake](https://github.com/aneesha/RAKE),
[YAKE!](https://github.com/LIAAD/yake), TF-IDF, etc.)
I wanted to create a very basic, but powerful method for extracting keywords and keyphrases.
This is where **KeyBERT** comes in! Which uses BERT-embeddings and simple cosine similarity
to find the sub-phrases in a document that are the most similar to the document itself.
First, document embeddings are extracted with BERT to get a document-level representation.
Then, word embeddings are extracted for N-gram words/phrases. Finally, we use cosine similarity
to find the words/phrases that are the most similar to the document. The most similar words could
then be identified as the words that best describe the entire document.
KeyBERT is by no means unique and is created as a quick and easy method
for creating keywords and keyphrases. Although there are many great
papers and solutions out there that use BERT-embeddings
(e.g.,
[1](https://github.com/pranav-ust/BERT-keyphrase-extraction),
[2](https://github.com/ibatra/BERT-Keyword-Extractor),
[3](https://www.preprints.org/manuscript/201908.0073/download/final_file),
), I could not find a BERT-based solution that did not have to be trained from scratch and
could be used for beginners (**correct me if I'm wrong!**).
Thus, the goal was a `pip install keybert` and at most 3 lines of code in usage.
<a name="gettingstarted"/></a>
## 2. Getting Started
[Back to ToC](#toc)
<a name="installation"/></a>
### 2.1. Installation
Installation can be done using [pypi](https://pypi.org/project/keybert/):
```
pip install keybert
```
You may want to install more depending on the transformers and language backends that you will be using. The possible installations are:
```
pip install keybert[flair]
pip install keybert[gensim]
pip install keybert[spacy]
pip install keybert[use]
```
<a name="usage"/></a>
### 2.2. Usage
The most minimal example can be seen below for the extraction of keywords:
```python
from keybert import KeyBERT
doc = """
Supervised learning is the machine learning task of learning a function that
maps an input to an output based on example input-output pairs. It infers a
function from labeled training data consisting of a set of training examples.
In supervised learning, each example is a pair consisting of an input object
(typically a vector) and a desired output value (also called the supervisory signal).
A supervised learning algorithm analyzes the training data and produces an inferred function,
which can be used for mapping new examples. An optimal scenario will allow for the
algorithm to correctly determine the class labels for unseen instances. This requires
the learning algorithm to generalize from the training data to unseen situations in a
'reasonable' way (see inductive bias).
"""
kw_model = KeyBERT()
keywords = kw_model.extract_keywords(doc)
```
You can set `keyphrase_ngram_range` to set the length of the resulting keywords/keyphrases:
```python
>>> kw_model.extract_keywords(doc, keyphrase_ngram_range=(1, 1), stop_words=None)
[('learning', 0.4604),
('algorithm', 0.4556),
('training', 0.4487),
('class', 0.4086),
('mapping', 0.3700)]
```
To extract keyphrases, simply set `keyphrase_ngram_range` to (1, 2) or higher depending on the number
of words you would like in the resulting keyphrases:
```python
>>> kw_model.extract_keywords(doc, keyphrase_ngram_range=(1, 2), stop_words=None)
[('learning algorithm', 0.6978),
('machine learning', 0.6305),
('supervised learning', 0.5985),
('algorithm analyzes', 0.5860),
('learning function', 0.5850)]
```
We can highlight the keywords in the document by simply setting `highlight`:
```python
keywords = kw_model.extract_keywords(doc, highlight=True)
```
<img src="images/highlight.png" width="75%" height="75%" />
**NOTE**: For a full overview of all possible transformer models see [sentence-transformer](https://www.sbert.net/docs/pretrained_models.html).
I would advise either `"all-MiniLM-L6-v2"` for English documents or `"paraphrase-multilingual-MiniLM-L12-v2"`
for multi-lingual documents or any other language.
<a name="maxsum"/></a>
### 2.3. Max Sum Distance
To diversify the results, we take the 2 x top_n most similar words/phrases to the document.
Then, we take all top_n combinations from the 2 x top_n words and extract the combination
that are the least similar to each other by cosine similarity.
```python
>>> kw_model.extract_keywords(doc, keyphrase_ngram_range=(3, 3), stop_words='english',
use_maxsum=True, nr_candidates=20, top_n=5)
[('set training examples', 0.7504),
('generalize training data', 0.7727),
('requires learning algorithm', 0.5050),
('supervised learning algorithm', 0.3779),
('learning machine learning', 0.2891)]
```
<a name="maximal"/></a>
### 2.4. Maximal Marginal Relevance
To diversify the results, we can use Maximal Margin Relevance (MMR) to create
keywords / keyphrases which is also based on cosine similarity. The results
with **high diversity**:
```python
>>> kw_model.extract_keywords(doc, keyphrase_ngram_range=(3, 3), stop_words='english',
use_mmr=True, diversity=0.7)
[('algorithm generalize training', 0.7727),
('labels unseen instances', 0.1649),
('new examples optimal', 0.4185),
('determine class labels', 0.4774),
('supervised learning algorithm', 0.7502)]
```
The results with **low diversity**:
```python
>>> kw_model.extract_keywords(doc, keyphrase_ngram_range=(3, 3), stop_words='english',
use_mmr=True, diversity=0.2)
[('algorithm generalize training', 0.7727),
('supervised learning algorithm', 0.7502),
('learning machine learning', 0.7577),
('learning algorithm analyzes', 0.7587),
('learning algorithm generalize', 0.7514)]
```
<a name="embeddings"/></a>
### 2.5. Embedding Models
KeyBERT supports many embedding models that can be used to embed the documents and words:
* Sentence-Transformers
* Flair
* Spacy
* Gensim
* USE
Click [here](https://maartengr.github.io/KeyBERT/guides/embeddings.html) for a full overview of all supported embedding models.
**Sentence-Transformers**
You can select any model from `sentence-transformers` [here](https://www.sbert.net/docs/pretrained_models.html)
and pass it through KeyBERT with `model`:
```python
from keybert import KeyBERT
kw_model = KeyBERT(model='all-MiniLM-L6-v2')
```
Or select a SentenceTransformer model with your own parameters:
```python
from keybert import KeyBERT
from sentence_transformers import SentenceTransformer
sentence_model = SentenceTransformer("all-MiniLM-L6-v2")
kw_model = KeyBERT(model=sentence_model)
```
**Flair**
[Flair](https://github.com/flairNLP/flair) allows you to choose almost any embedding model that
is publicly available. Flair can be used as follows:
```python
from keybert import KeyBERT
from flair.embeddings import TransformerDocumentEmbeddings
roberta = TransformerDocumentEmbeddings('roberta-base')
kw_model = KeyBERT(model=roberta)
```
You can select any 🤗 transformers model [here](https://huggingface.co/models).
## Citation
To cite KeyBERT in your work, please use the following bibtex reference:
```bibtex
@misc{grootendorst2020keybert,
author = {Maarten Grootendorst},
title = {KeyBERT: Minimal keyword extraction with BERT.},
year = 2020,
publisher = {Zenodo},
version = {v0.3.0},
doi = {10.5281/zenodo.4461265},
url = {https://doi.org/10.5281/zenodo.4461265}
}
```
## References
Below, you can find several resources that were used for the creation of KeyBERT
but most importantly, these are amazing resources for creating impressive keyword extraction models:
**Papers**:
* Sharma, P., & Li, Y. (2019). [Self-Supervised Contextual Keyword and Keyphrase Retrieval with Self-Labelling.](https://www.preprints.org/manuscript/201908.0073/download/final_file)
**Github Repos**:
* https://github.com/thunlp/BERT-KPE
* https://github.com/ibatra/BERT-Keyword-Extractor
* https://github.com/pranav-ust/BERT-keyphrase-extraction
* https://github.com/swisscom/ai-research-keyphrase-extraction
**MMR**:
The selection of keywords/keyphrases was modeled after:
* https://github.com/swisscom/ai-research-keyphrase-extraction
**NOTE**: If you find a paper or github repo that has an easy-to-use implementation
of BERT-embeddings for keyword/keyphrase extraction, let me know! I'll make sure to
add a reference to this repo.
%prep
%autosetup -n keybert-0.7.0
%build
%py3_build
%install
%py3_install
install -d -m755 %{buildroot}/%{_pkgdocdir}
if [ -d doc ]; then cp -arf doc %{buildroot}/%{_pkgdocdir}; fi
if [ -d docs ]; then cp -arf docs %{buildroot}/%{_pkgdocdir}; fi
if [ -d example ]; then cp -arf example %{buildroot}/%{_pkgdocdir}; fi
if [ -d examples ]; then cp -arf examples %{buildroot}/%{_pkgdocdir}; fi
pushd %{buildroot}
if [ -d usr/lib ]; then
find usr/lib -type f -printf "/%h/%f\n" >> filelist.lst
fi
if [ -d usr/lib64 ]; then
find usr/lib64 -type f -printf "/%h/%f\n" >> filelist.lst
fi
if [ -d usr/bin ]; then
find usr/bin -type f -printf "/%h/%f\n" >> filelist.lst
fi
if [ -d usr/sbin ]; then
find usr/sbin -type f -printf "/%h/%f\n" >> filelist.lst
fi
touch doclist.lst
if [ -d usr/share/man ]; then
find usr/share/man -type f -printf "/%h/%f.gz\n" >> doclist.lst
fi
popd
mv %{buildroot}/filelist.lst .
mv %{buildroot}/doclist.lst .
%files -n python3-keybert -f filelist.lst
%dir %{python3_sitelib}/*
%files help -f doclist.lst
%{_docdir}/*
%changelog
* Tue Apr 25 2023 Python_Bot <Python_Bot@openeuler.org> - 0.7.0-1
- Package Spec generated
|