OPERATOR-Object {RGMQL} | R Documentation |
This class constructor is used to create instances of OPERATOR object, to be used in GMQL functions that require operator on value.
META(value, type = NULL) NIL(type) SQRT(value)
value |
string identifying name of metadata attribute |
type |
string identifying the type of the attribute value; it must be: INTEGER, DOUBLE or STRING. For NIL() function, only INTEGER and DOUBLE are allowed |
META: It prepares input parameter to be passed to library function meta, performing all the type conversions needed
SQRT: It prepares input parameter to be passed to library function sqrt, performing all the type conversions needed
NIL: It prepares input parameter to be passed to library function null, performing all the type conversions needed
Operator object
## This statement initializes and runs the GMQL server for local execution ## and creation of results on disk. Then, with system.file() it defines ## the path to the folder "DATASET" in the subdirectory "example" ## of the package "RGMQL" and opens such folder as a GMQL dataset ## named "exp" init_gmql() test_path <- system.file("example", "DATASET", package = "RGMQL") exp = read_gmql(test_path) ## This statement allows to select, in all input samples, all those regions ## for which the region attribute score has a value which is greater ## than the metadata attribute value "avg_score" in their sample. data = filter(exp, r_predicate = score > META("avg_score")) ## This statement defines new numeric region attributes with "null" value. ## The syntax for creating a new attribute with null value is ## attribute_name = NULL(TYPE), where type may be INTEGER or DOUBLE. out = select(exp, regions_update = list(signal = NIL("INTEGER"), pvalue = NIL("DOUBLE"))) ## This statement allows to build an output dataset named 'out' such that ## all the samples from the input dataset 'exp' are conserved, ## as well as their region attributes (and their values) ## and their metadata attributes (and their values). ## The new metadata attribute 'concSq' is added to all output samples ## with value correspondent to the mathematical squared root ## of the pre-existing metadata attribute 'concentration'. out = select(exp, metadata_update = list(concSq = SQRT("concentration")))