extract_keywords: Function to extract rows from a lookup table based on...
In rEHR: Manipulating and Analysing Electronic Health Record Data

Description Usage Arguments Details Value Examples

This function can be used to build draft clinical code lists based on a clinical or product lookup table and a set of keywords.

1	extract_keywords(lookup, keywords, keyword_field = "desc")

`lookup`	a dataframe containing a lookup table
`keywords`	character vector containing the keyword terms to search for
`keyword_field`	character identifying the field in the lookup table to be searched for keywords

See www.clinicalcodes.org for clinical code lists that have been used in previous studies

All keywords are collapsed together in an OR statement

a data frame subsetted by keyword

## Not run: 
keywords <- c('oral ulceration', 'mouth ulceration', 'aphthous ulceration', 
'oral aphthous ulceration','oral ulcer[s]?', 'mouth ulcer[s]?', 'aphthous ulcer[s]?', 
'aphthous stomatitis', "stomatitis", "aphthae", 'oral aphthous stomatitis', 
'oral aphthous ulcers', 'recurrent oral ulcers', 'recurrent mouth ulcers', 
'recurrent oral aphthous ulcers', 'recurrent aphthous ulcers', 'recurrent aphthous stomatitis', 
'recurrent oral aphthous stomatitis')
a <- extract_keywords(medical, keywords)

## End(Not run)