query
Query an Object for Information
The function query can be used to search an object
for a keyword.
The data.set and importer methods perform such a search
through the annotations and value labels of
the items in the data set.
- Keywords
- manip
Usage
query(x,pattern,…)
# S4 method for data.set
query(x,pattern,…)
# S4 method for importer
query(x,pattern,…)# S4 method for item
query(x,pattern,…)
# (Called by the methods above.)
Arguments
- x
an object
- pattern
a character string that gives the pattern to be searched for
- …
optional arguments such as
fuzzylogical, TRUE by default; use fuzzy search via
agrepor regexp search viagrepextendedlogical, defaults to FALSE; passed to
grepperllogical, defaults to TRUE; passed to
grepfixedlogical, defaults to TRUE; passed to
grepignore.caseinsertionsnumerical value, defaults to 0.999999999; passed to
agrepdeletionsnumerical value, defaults to 0; passed to
agrepsubstitutionsnumerical value, defaults to 0; passed to
agrep
Value
If both the annotation and the value labels of an item match the pattern
the query method for 'item' objects returns a list containing the annotation
and the value labels, otherwise if only the annotation or the value labels
match the pattern, either the annotation or the value labels are returned,
otherwise if neither matches the pattern, query returns NULL.
The methods of query for 'data.set' and 'importer' objects return
a list of all non-NULL query results of all items contained by these
objects, or NULL.
Examples
# NOT RUN {
nes1948.por <- unzip(system.file("anes/NES1948.ZIP",package="memisc"),
"NES1948.POR",exdir=tempfile())
nes1948 <- spss.portable.file(nes1948.por)
query(nes1948,"TRUMAN")
# }