View source: R/termExtraction.R
termExtraction | R Documentation |
It extracts terms from a text field (abstract, title, author's keywords, etc.) of a bibliographic data frame.
termExtraction(
M,
Field = "TI",
ngrams = 1,
stemming = FALSE,
language = "english",
remove.numbers = TRUE,
remove.terms = NULL,
keep.terms = NULL,
synonyms = NULL,
verbose = TRUE
)
M |
is a data frame obtained by the converting function | ||||||||||||
Field |
is a character object. It indicates the field tag of textual data :
The default is | ||||||||||||
ngrams |
is an integer between 1 and 3. It indicates the type of n-gram to extract from texts.
An n-gram is a contiguous sequence of n terms. The function can extract n-grams composed by 1, 2, 3 or 4 terms. Default value is | ||||||||||||
stemming |
is logical. If TRUE the Porter Stemming algorithm is applied to all extracted terms. The default is | ||||||||||||
language |
is a character. It is the language of textual contents ("english", "german","italian","french","spanish"). The default is | ||||||||||||
remove.numbers |
is logical. If TRUE all numbers are deleted from the documents before term extraction. The default is | ||||||||||||
remove.terms |
is a character vector. It contains a list of additional terms to delete from the corpus after term extraction. The default is | ||||||||||||
keep.terms |
is a character vector. It contains a list of compound words "formed by two or more terms" to keep in their original form in the term extraction process. The default is | ||||||||||||
synonyms |
is a character vector. Each element contains a list of synonyms, separated by ";", that will be merged into a single term (the first word contained in the vector element). The default is | ||||||||||||
verbose |
is logical. If TRUE the function prints the most frequent terms extracted from documents. The default is |
the bibliometric data frame with a new column containing terms about the field tag indicated in the argument Field
.
convert2df
to import and convert an WoS or SCOPUS Export file in a bibliographic data frame.
biblioAnalysis
function for bibliometric analysis
# Example 1: Term extraction from titles
data(scientometrics, package = "bibliometrixData")
# vector of compound words
keep.terms <- c("co-citation analysis","bibliographic coupling")
# term extraction
scientometrics <- termExtraction(scientometrics, Field = "TI", ngrams = 1,
remove.numbers=TRUE, remove.terms=NULL, keep.terms=keep.terms, verbose=TRUE)
# terms extracted from the first 10 titles
scientometrics$TI_TM[1:10]
#Example 2: Term extraction from abstracts
data(scientometrics)
# term extraction
scientometrics <- termExtraction(scientometrics, Field = "AB", ngrams = 2,
stemming=TRUE,language="english",
remove.numbers=TRUE, remove.terms=NULL, keep.terms=NULL, verbose=TRUE)
# terms extracted from the first abstract
scientometrics$AB_TM[1]
# Example 3: Term extraction from keywords with synonyms
data(scientometrics)
# vector of synonyms
synonyms <- c("citation; citation analysis", "h-index; index; impact factor")
# term extraction
scientometrics <- termExtraction(scientometrics, Field = "ID", ngrams = 1,
synonyms=synonyms, verbose=TRUE)
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