Add/remove custom stop words with spacy

What is the best way to add/remove stop words with spacy? I am using token.is_stop function and would like to make some custom changes to the set. I was looking at the documentation but could not find anything regarding of stop words. Thanks!

Using Spacy 2.0.11, you can update its stopwords set using one of the following:

To add a single stopword:

import spacy    
nlp = spacy.load("en")
nlp.Defaults.stop_words.add("my_new_stopword")

To add several stopwords at once:

import spacy    
nlp = spacy.load("en")
nlp.Defaults.stop_words |= {"my_new_stopword1","my_new_stopword2",}

To remove a single stopword:

import spacy    
nlp = spacy.load("en")
nlp.Defaults.stop_words.remove("whatever")

To remove several stopwords at once:

import spacy    
nlp = spacy.load("en")
nlp.Defaults.stop_words -= {"whatever", "whenever"}

Note: To see the current set of stopwords, use:

print(nlp.Defaults.stop_words)

Update : It was noted in the comments that this fix only affects the current execution. To update the model, you can use the methods nlp.to_disk("/path") and nlp.from_disk("/path") (further described at https://spacy.io/usage/saving-loading).

You can edit them before processing your text like this (see this post):

>>> import spacy
>>> nlp = spacy.load("en")
>>> nlp.vocab["the"].is_stop = False
>>> nlp.vocab["definitelynotastopword"].is_stop = True
>>> sentence = nlp("the word is definitelynotastopword")
>>> sentence[0].is_stop
False
>>> sentence[3].is_stop
True

Note: This seems to work <=v1.8. For newer versions, see other answers.

For version 2.0 I used this:

from spacy.lang.en.stop_words import STOP_WORDS

print(STOP_WORDS) # <- set of Spacy's default stop words

STOP_WORDS.add("your_additional_stop_word_here")

for word in STOP_WORDS:
    lexeme = nlp.vocab[word]
    lexeme.is_stop = True

This loads all stop words into a set.

You can amend your stop words to STOP_WORDS or use your own list in the first place.

For 2.0 use the following:

for word in nlp.Defaults.stop_words:
    lex = nlp.vocab[word]
    lex.is_stop = True

This collects the stop words too :)

spacy_stopwords = spacy.lang.en.stop_words.STOP_WORDS

In latest version following would remove the word out of the list:

spacy_stopwords = spacy.lang.en.stop_words.STOP_WORDS
spacy_stopwords.remove('not')

For version 2.3.0 If you want to replace the entire list instead of adding or removing a few stop words, you can do this:

custom_stop_words = set(['the','and','a'])

# First override the stop words set for the language
cls = spacy.util.get_lang_class('en')
cls.Defaults.stop_words = custom_stop_words

# Now load your model
nlp = spacy.load('en_core_web_md')

The trick is to assign the stop word set for the language before loading the model. It also ensures that any upper/lower case variation of the stop words are considered stop words.