abstract_to_text        concatenates abstract list to a single string
chunker                 Helper function to split a vector v into list
                        of chunks of chunk_size
entrez_email            Set global variables
fetch_in_chunks         Downloads abstracts and Metadata from Pubmed,
                        storing as R objects
geocode                 Helper function for geocode_address
geocode_address         Function to get coordinates from a supplied
                        address If no match is found, it recursively
                        calls itself on the address minus the first
                        line of the address
geocode_addresses       Returns a data frame of geocoded addresses with
                        longitude and latitudes Uses the Google Maps
                        geocode API
get_article_location_data
                        Extracts addresses of affiliated departments
                        from Pubmed metadata email addresses are
                        cleaned out.
get_articles_by_terms   Returns a list of articles matching the
                        termlist items in the termlist can be strings
                        or character vectors, concatenated to an "or"
                        regex e.g list(c("gprd", "diabetes")) returns
                        all articles mentioning either gprd or
                        diabetes. different items in the list
                        recursively filter the list e.g. list("gprd",
                        "diabetes") returns articles mentioning gprd
                        and diabtes
get_mesh_headings       Returns a list of MeSH headings for an article
in_abstract_p           predicate function for searching abstracts
in_mesh_abstract_p      predicate function for searching abstracts and
                        MeSH headings
in_mesh_headings_p      predicate function for searching MeSH headings
in_record_text_p        predicate function for searching in title and
                        abstract
keyword_assoc_table     Builds an association table for a character
                        vector of search terms in a corpus. This can
                        then e.g. be fed into igraph to generate an
                        adjacency graph of terms Different column names
                        can be set for the association matrix if e.g.
                        complex regex terms are used for the
                        keyword_list
mesh_assoc_table        Builds an association matrix for all MeSH terms
                        in an article corpus
mesh_heading_frequency
                        Returns a data frame of all MeSH headings in a
                        corpus, with frequencies for each
mesh_table              helper function for mesh_assoc_table
mesh_to_text            concatenates a list of MeSH headings to a
                        single string
pubmed_fetch            Download data from Pubmed
read_article_json       Redundant wrapper around fromJSON
record_counts_by_year   Gives a breakdown of records per year in a
                        corpus of Pubmed Records
term_in_text_p          predicate function for presence of a term in an
                        article text
title_to_text           concatenates a list of MeSH headings to a
                        single string
write_JSON_file         Write a list of (e.g.) Pubmed records (e.g.)
                        from rpubmed_fetch_in_chunks to json file
write_record_list       Writes article title and citation data to file
                        or stdout.  Can optionally also output
                        abstracts and output as Markdown, with
                        customisable line starts, e.g. for unordered
                        lists
