import pandas as pd
import os
import datetime
-from nltk import wordpunct_tokenize, MWETokenizer
+import re
+from nltk import wordpunct_tokenize, MWETokenizer, sent_tokenize
+from nltk.corpus import stopwords
+from nltk.util import ngrams
+import string
+from random import random
+
+# remove urls
+# taken from https://stackoverflow.com/questions/3809401/what-is-a-good-regular-expression-to-match-a-url
+urlregex = re.compile(r"[-a-zA-Z0-9@:%._\+~#=]{1,256}\.[a-zA-Z0-9()]{1,6}\b([-a-zA-Z0-9()@:%_\+.~#?&//=]*)")
# compute term frequencies for comments in each subreddit by week
-def weekly_tf(partition):
+def weekly_tf(partition, mwe_pass = 'first'):
dataset = ds.dataset(f'/gscratch/comdata/output/reddit_comments_by_subreddit.parquet/{partition}', format='parquet')
- batches = dataset.to_batches(columns=['CreatedAt','subreddit','body'])
+
+ if not os.path.exists("/gscratch/comdata/users/nathante/reddit_comment_ngrams_10p_sample/"):
+ os.mkdir("/gscratch/comdata/users/nathante/reddit_comment_ngrams_10p_sample/")
+
+ if not os.path.exists("/gscratch/comdata/users/nathante/reddit_tfidf_test_authors.parquet_temp/"):
+ os.mkdir("/gscratch/comdata/users/nathante/reddit_tfidf_test_authors.parquet_temp/")
+
+ ngram_output = partition.replace("parquet","txt")
+
+ if os.path.exists(f"/gscratch/comdata/users/nathante/reddit_comment_ngrams_10p_sample/{ngram_output}"):
+ os.remove(f"/gscratch/comdata/users/nathante/reddit_comment_ngrams_10p_sample/{ngram_output}")
+
+ batches = dataset.to_batches(columns=['CreatedAt','subreddit','body','author'])
schema = pa.schema([pa.field('subreddit', pa.string(), nullable=False),
pa.field('term', pa.string(), nullable=False),
pa.field('tf', pa.int64(), nullable=False)]
)
+ author_schema = pa.schema([pa.field('subreddit', pa.string(), nullable=False),
+ pa.field('author', pa.string(), nullable=False),
+ pa.field('week', pa.date32(), nullable=False),
+ pa.field('tf', pa.int64(), nullable=False)]
+ )
+
dfs = (b.to_pandas() for b in batches)
def add_week(df):
subreddit_weeks = groupby(rows, lambda r: (r.subreddit, r.week))
- tokenizer = MWETokenizer()
+ mwe_tokenize = MWETokenizer().tokenize
+
+ def remove_punct(sentence):
+ new_sentence = []
+ for token in sentence:
+ new_token = ''
+ for c in token:
+ if c not in string.punctuation:
+ new_token += c
+ if len(new_token) > 0:
+ new_sentence.append(new_token)
+ return new_sentence
+
+
+ stopWords = set(stopwords.words('english'))
+
+ # we follow the approach described in datta, phelan, adar 2017
+ def my_tokenizer(text):
+ # remove stopwords, punctuation, urls, lower case
+ # lowercase
+ text = text.lower()
+
+ # remove urls
+ text = urlregex.sub("", text)
+
+ # sentence tokenize
+ sentences = sent_tokenize(text)
+
+ # wordpunct_tokenize
+ sentences = map(wordpunct_tokenize, sentences)
+
+ # remove punctuation
+
+ sentences = map(remove_punct, sentences)
+
+ # remove sentences with less than 2 words
+ sentences = filter(lambda sentence: len(sentence) > 2, sentences)
+
+ # datta et al. select relatively common phrases from the reddit corpus, but they don't really explain how. We'll try that in a second phase.
+ # they say that the extract 1-4 grams from 10% of the sentences and then find phrases that appear often relative to the original terms
+ # here we take a 10 percent sample of sentences
+ if mwe_pass == 'first':
+ sentences = list(sentences)
+ for sentence in sentences:
+ if random() <= 0.1:
+ grams = list(chain(*map(lambda i : ngrams(sentence,i),range(4))))
+ with open(f'/gscratch/comdata/users/nathante/reddit_comment_ngrams_10p_sample/{ngram_output}','a') as gram_file:
+ for ng in grams:
+ gram_file.write(' '.join(ng) + '\n')
+ for token in sentence:
+ if token not in stopWords:
+ yield token
+
+ else:
+ # remove stopWords
+ sentences = map(lambda s: filter(lambda token: token not in stopWords, s), sentences)
+ return chain(* sentences)
def tf_comments(subreddit_weeks):
for key, posts in subreddit_weeks:
subreddit, week = key
tfs = Counter([])
-
+ authors = Counter([])
for post in posts:
- tfs.update(tokenizer.tokenize(wordpunct_tokenize(post.body.lower())))
+ tokens = my_tokenizer(post.body)
+ tfs.update(tokens)
+ authors.update([post.author])
for term, tf in tfs.items():
- yield [subreddit, term, week, tf]
-
+ yield [True, subreddit, term, week, tf]
+
+ for author, tf in authors.items():
+ yield [False, subreddit, author, week, tf]
+
outrows = tf_comments(subreddit_weeks)
outchunksize = 10000
- with pq.ParquetWriter("/gscratch/comdata/users/nathante/reddit_tfidf_test.parquet_temp/{partition}",schema=schema,compression='snappy',flavor='spark') as writer:
+ with pq.ParquetWriter("/gscratch/comdata/users/nathante/reddit_tfidf_test.parquet_temp/{partition}",schema=schema,compression='snappy',flavor='spark') as writer, pq.ParquetWriter("/gscratch/comdata/users/nathante/reddit_tfidf_test_authors.parquet_temp/{partition}",schema=author_schema,compression='snappy',flavor='spark') as author_writer:
while True:
chunk = islice(outrows,outchunksize)
- pddf = pd.DataFrame(chunk, columns=schema.names)
+ pddf = pd.DataFrame(chunk, columns=["is_token"] + schema.names)
+ print(pddf)
+ author_pddf = pddf.loc[pddf.is_token == False]
+ author_pddf = author_pddf.rename({'term':'author'}, axis='columns')
+ author_pddf = author_pddf.loc[:,author_schema.names]
+
+ pddf = pddf.loc[pddf.is_token == True, schema.names]
+
print(pddf)
+ print(author_pddf)
table = pa.Table.from_pandas(pddf,schema=schema)
+ author_table = pa.Table.from_pandas(author_pddf,schema=author_schema)
if table.shape[0] == 0:
break
writer.write_table(table)
-
+ author_writer.write_table(author_table)
+
writer.close()
+ author_writer.close()
def gen_task_list():
projects / cdsc_reddit.git / blobdiff