nlp-pipeline 0.0.35

Pipelines and management structure for NLP analysis of a corpus of texts

nlp_pipeline

Collection of NLP tools for processing and analyzing text data.

Introduction

The fundamental input of the library is a metadata file. By default this will contain the columns ["text_id", "web_filepath", "local_raw_filepath", "local_txt_filepath", "detected_language"]. The only one that needs to be provided by the user is "web_filepath". Ergo, a list of URLs containing text documents is all that is required to use the library. If the corpus had additional columns of interest, like titles, etc., those can be passed via the metadata_addt_column_names argument when instantiating the initial nlp_processor function. More information below.

Fundamentally the library takes the list of documents and downloads, transforms, and organizes them according to a specific filestructure. These files can then be used to generate insights, such as word counts, etc.

For more detailed examples, see the nlp_pipeline_example.zip file. Note the trained BERTopic model is not stored there due to space constraints and needs to be retrained.

Example code

from nlp_pipeline.nlp_pipeline import nlp_processor

# additional columns I want to track in the metadata
metadata_addt_column_names = ["title", "year"] 

# instantiating the processor object
processor = nlp_processor(
	data_path = "path_to_store_text_documents/",
	metadata_addt_column_names = metadata_addt_column_names,
	windows_tesseract_path = "path_to_tesseract.exe", # if on Windows, otherwise leave blank and have it installed in your path
	windows_poppler_path = "path_to_poppler/bin" # if on Windows, otherwise leave blank and have it installed in your path
)

# this will generate a metadata file and create the directory structure
# you can now add additional data to the metadata file, (titles, etc.). When finished, run the following so the metadata in the processor object will reflect the local file
# in the web_filepath metadata column you can also put paths to local .txt files
processor.refresh_object_metadata()

# if you ever make changes to the local files, e.g., delete a PDF, run the following to make sure the metadata file reflects that
processor.sync_local_metadata()

# download some documents with metadata IDs 1, 2, and 3
text_ids = [1,2,3]
processor.download_text_id(text_ids)

# edit the PDFs to be a selection of pages
processor.filter_pdf_pages(page_num_column = "page_nums") # "page_nums" is then a column in the metadata file with values like "1:10,24,27:29", leave row blank to keep all pages of the PDF

# convert the PDFs or HTMLs to .txt
processor.convert_to_text(text_ids)

# transform the text (stemming, etc.)
# run help(processor.transform_text) for more information
processor.transform_text(
        text_ids = text_ids,
        path_prefix = "all_transformed", # what to prefix the files with this transformation
        perform_lower = True, # lower case the text
        perform_replace_newline_period = True, # replace periods and newline characters with |
        perform_remove_punctuation = True, # remove punctuation marks
        perform_remove_stopwords = True, # remove stopwords (the, and, etc.)
        perform_stemming = True, # stem the words (run = runs, etc.)
        stemmer = "snowball" # which stemmer to use. If in doubt, use snowball
)

# from the transformed text, generate a CSV with word counts in each document
processor.gen_word_count_csv(
        text_ids = text_ids, 
        path_prefix = "all_transformed", # prefix used previously for the transformation
        exclude_words = ["for"] # list of words to not include in the word counts
)

# from the raw, untransformed text, generate a CSV with entity counts in each document
processor.gen_entity_count_csv(
	text_ids = text_ids
)

# get sentiment of a group of texts
processor.gen_sentiment_csv(text_ids, "all_transformed")

# get n_words, sentences, and pages of texts
processor.gen_summary_stats_csv(text_ids, "all_transformed")

# bar plot of most common words in a document or group of documents
p, plot_df = processor.bar_plot_word_count(
	text_ids = text_ids, 
	path_prefix = "all_transformed", # prefix used previously for the transformation. Pass "entity" to show top entities instead of words
	n_words = 10, # top n words to show
	title = "Plot Title"
)

# word cloud of most common words in a document or group of documents
p, plot_df = processor.word_cloud(
	text_ids = text_ids, 
	path_prefix = "all_transformed", # prefix used previously for the transformation. Pass "entity" to show top entities instead of words
	n_words = 10 # top n words to show
)

# plot of word occurrences over time
p, plot_df = processor.plot_word_occurrences(
    text_ids_list = text_ids, # can be a list of lists, [[1,2,3], [4,5,6]], for counts by decade e.g.
    word = "green", 
    path_prefix = "all_transformed", # pass "entity" plot entity instead of word over time
    x_labels = [1,2,3],
    title = "Plot Title"
)

# plot average sentiment or neutral proportion in documents
p, plot_df = processor.plot_sentiment(
    text_ids_list = text_ids, 
    path_prefix = "all_transformed", 
    x_labels = [1,2,3],
    sentiment_col = "neutral_proportion",
    title = "Plot Title"
)

# plot various summary stats in documents
p, plot_df = processor.plot_summary_stats(
    text_ids_list = text_ids, 
    path_prefix = "all_transformed", 
    x_labels = [1,2,3],
    summary_stats_col = "n_words", # one of: n_words, n_unique_words, n_sentences, n_pages, avg_word_length, avg_word_incidence, num_chars_numeric, num_chars_alpha, numeric_proportion
    title = "Plot Title"
)

# get data on search terms in the documents
processor.gen_search_terms(
	group_name = "all_documents",
	text_ids = text_ids,
	search_terms_df = pd.DataFrame({"theme": ["theme1", "theme1"], "permutation": ["word1", "word2"]}),
	path_prefix = "all_transformed",
	character_buffer = 100
)

# get data on search terms with multiple groups of documents in one file
processor.gen_aggregated_search_terms(
	group_names = ["2001", "2002"],
	text_ids = [[1,2], [3,4]],
	search_terms_df = search_terms_df,
	path_prefix = "all_transformed",
	character_buffer = 100
)

# get a list of top n co-occurring word counts from a previous gen_search_terms run
processor.gen_co_occurring_terms(
	group_name = "all_documents", # must be the same as a previous gen_search_terms run
	co_occurrence_terms_df = pd.DataFrame({"theme": ["theme1", "theme1"], "permutation": ["word1", ""]}), # for the second one, it will search the whole corpus of "theme1" permutations for co-occurring words
	n_words = 50
)

# get counts of words that occur within the context of a previous gen_search_terms run
processor.gen_second_level_search_terms(
	group_name = "all_documents", # must be the same as a previous gen_search_terms run 
	second_level_search_terms_df = pd.DataFrame({"theme": ["theme1", "theme1"], "permutation": ["word1", ""], "second_level_search_term": ["newword1", "newword2"})
)

# get sentence-by-sentence sentiment report for a string or text_id
sentiment_report = processor.gen_sentiment_report(text_id = 1) # to generate for a text_id
sentiment_report = processor.gen_sentiment_report(stringx = "a new string.") # to generate for a new string

# similarity heat map plot between documents
p, plot_df, xaxis_labels = processor.plot_text_similarity(text_ids, label_column = "text_id")

# similarity of documents cluster plot
plot_df = processor.gen_cluster_df(text_id_dict) # dictionary of groups and text_ids within the group
p = processor.plot_cluster(plot_df, color_column = "group")

# train a BERTopic model on a set of documents
processor.train_bertopic_model(
	text_ids = [1,2,3], # which text ids to include in the model
	model_name = "test_model", # will save the model under this directory in the data_path/bertopic_models/ path
	notes = "notes", # notes on this model
	split_by_n_words = None # leave None to split longer documents by page, or put an integer to split them by that number of words
)

# load a trained BERTopic model
model = processor.load_bertopic_model(model_name)

# save various visualizations from BERTopic models to data_path/bertopic_models/model_name/
# any visualizations from: https://maartengr.github.io/BERTopic/getting_started/visualization/visualization.html, e.g.:
processor.visualize_bertopic_model(
	model_name = "test_model",
	method_name = "visualize_topics", # method name from BERTopics various options
	plot_name = "plot_name"
)

# other options for method_name:
[
	"visualize_topics",
	"visualize_documents",
	"visualize_hierarchy",
	"visualize_barchart",
	"visualize_heatmap",
	"visualize_topics_over_time",
	"visualize_topics_presence" # this is a unique function which shows a heat map of the relative presence of different topics in each document
]

# you can also pass arguments for these methods, e.g.:
processor.visualize_bertopic_model(
	model_name = "test_model",
	method_name = "visualize_topics", # method name from BERTopics various options
	plot_name = "plot_name",
	top_n_topics = 10 # this is an argument for the visualize_topics function
)

# visualize_topics_over_time also requires you to pass a list of timestamps (datetime.datetime type) corresponding to the dates of the original documents the model was trained on
processor.visualize_bertopic_model(
	model_name = "test_model",
	method_name = "visualize_topics_over_time", # method name from BERTopics various options
	plot_name = "plot_name",
	timestamps = timestamps # a list of timestamps
)

# visualize presence of topics in documents
processor.visualize_bertopic_model(
	model_name = "test_model",
	method_name = "visualize_topics_presence",
	plot_name = "plot_name",
	presence_text_ids = [0, 1, 2], # only produce the plot for these text ids
	presence_topic_ids = [5, 6, 7] # only produce the plot for these topic ids
)

Different language support

• removing of stopwords
  • most big languages, full list with from nltk.corpus import stopwords; print(stopwords.fileids())
• stemming
  • for Snowball stemmer, many big languages, but less than stopwords support. Full list here. Only English for Lancaster stemmer.
• word counts
  • all languages
• entity counts
  • most big languages, full list here
• sentiment analysis
  • only English
• summary statistics (number of words, pages, numeric proportion, etc.)
  • all languages
• search term sentiment and context
  • only English for sentiment, all languages for context
• text similarity/clustering
  • all languages
• topic modelling
  • most big languages, full list here