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
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
KWIC containing 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.|
Knüpffer, H. 1988. "The European Barley Database of the ECP/GR: An Introduction." Die Kulturpflanze 36 (1): 135-62. doi: 10.1007/BF01986957.
Knüpffer, H., L. Frese, and M. W. M. Jongen. 1997. "Using Central Crop Databases: Searching for Duplicates and Gaps." In Central Crop Databases: Tools for Plant Genetic Resources Management. Report of a Workshop, Budapest, Hungary, 13-16 October 1996, edited by E. Lipman, M. W. M. Jongen, T. J. L. van Hintum, T. Gass, and L. Maggioni, 67-77. Rome, Italy and Wageningen, The Netherlands: International Plant Genetic Resources Institute and Centre for Genetic Resources.
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# 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)
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