Create a KWIC Index
KWIC creates a Keyword in Context index from PGR passport database
KWIC(x, fields, min.freq = 10)
- A data frame from which KWIC index is to be generated.
- A character vector with the names of fields(columns) of the data frame from which KWIC index is to be generated. The first field is considered as the primary key or identifier (see Details).
- Frequency of keywords are not computed if below
min.freq. Default is 10.
The function generates a Keyword in Context index from a data frame of a PGR
passport database based on the fields(columns) stated in the arguments, using
The first element of vector
fields is considered as the primary key or
identifier which uniquely identifies all rows in the data frame.
Cleaning of the data the input fields(columns) using the
DataClean function with appropriate arguments is
suggested before running this function.
A list of class
KWICcontaining the following components:
|The KWIC index in the form of a data frame.|
| A data frame of the keywords detected with
frequency greater than
|A character vector with the names of the PGR database fields from which the keywords were extracted.|
Knupffer, H. (1988). The European Barley Database of the ECP/GR: an introduction. Die Kulturpflanze, 36(1), 135-162. Knupffer, H., Frese, L., & Jongen, M. W. M. (1997). Using central crop databases: searching for duplicates and gaps. In: E. Lipman, M. W. M. Jongen, T. J. L. van Hintum, T. Gass, and L. Maggioni (Eds.), Central Crop Databases: Tools for Plant Genetic Resources Management (pp. 67-77). Rome, Italy: International Plant Genetic Resources Institute/ Wageningen, The Netherlands: Centre for Genetic Resources.
# Load PGR passport database GN <- GN1000 # Specify as a vector the database fields to be used GNfields <- c("NationalID", "CollNo", "DonorID", "OtherID1", "OtherID2") # Clean the data GN[GNfields] <- lapply(GN[GNfields], function(x) DataClean(x)) ## Not run: # # # Generate KWIC index # GNKWIC <- KWIC(GN, GNfields) # GNKWIC # # # Retrieve the KWIC index from the KWIC object # KWIC <- GNKWIC[] # # # Retrieve the keyword frequencies from the KWIC object # KeywordFreq <- GNKWIC[] # # # Show error in case of duplicates and NULL values # # in the primary key/ID field "NationalID" # GN[1001:1005,] <- GN[1:5,] # GN[1001,3] <- "" # GNKWIC <- KWIC(GN, GNfields) # ## End(Not run)