California Digital
Library
Clustering :: Preprocessing
lconvert to
lowercase
lremove punctuation
ldelete words with £ 2 characters
lreplace collocations
(e.g. war_relocation_authority)
lapply stemming (‘rivers’
à ‘river’)
ldelete words starting
with a digit (e.g., dates)
ldelete words in stopword
list
ldelete infrequent words
(< 10 occurrences)