keywords = [token.text for token in doc if token.is_alpha and not token.is_stop]

This line is extracting keywords from a text document (doc) using a list comprehension. Here’s how it works:

• for token in doc: Iterates over each token (word or punctuation) in the document doc.
• token.is_alpha: This condition checks if the token is made up of alphabetic characters (i.e., no numbers or punctuation). This helps to filter out tokens that are not words.
• not token.is_stop: This condition checks if the token is not a “stop word.” Stop words are common words like “the”, “is”, “in”, etc., that are usually ignored in text analysis because they don’t carry significant meaning.

So, this line collects all words in the document that are alphabetic and not stop words. These are typically the key terms or important words in the text.