mgu74aMAPCOUNTS {mgu74a.db} | R Documentation

## Number of mapped keys for the maps in package mgu74a.db

### Description

mgu74aMAPCOUNTS provides the "map count" (i.e. the count of mapped keys) for each map in package mgu74a.db.

### Details

This "map count" information is precalculated and stored in the package annotation DB. This allows some quality control and is used by the `checkMAPCOUNTS` function defined in AnnotationDbi to compare and validate different methods (like `count.mappedkeys(x)` or `sum(!is.na(as.list(x)))`) for getting the "map count" of a given map.

### See Also

`mappedkeys`, `count.mappedkeys`, `checkMAPCOUNTS`

### Examples

      mgu74aMAPCOUNTS
      mapnames <- names(mgu74aMAPCOUNTS)
      mgu74aMAPCOUNTS[mapnames[1]]
      x <- get(mapnames[1])
      sum(!is.na(as.list(x)))
      count.mappedkeys(x)   # much faster!

      ## Check the "map count" of all the maps in package mgu74a.db
      checkMAPCOUNTS("mgu74a.db")

[Package mgu74a.db version 2.2.5 Index]