R: Assigning the number of rows or columns

nrowAssign {ff} | R Documentation

## Assigning the number of rows or columns

### Description

Function `nrow<-` assigns `dim` with a new number of rows.
Function `ncol<-` assigns `dim` with a new number of columns.

### Usage

    nrow(x) <- value
    ncol(x) <- value

### Arguments

`x` | a object that has `dim` AND can be assigned ONE new dimension
`value` | the new size of the assigned dimension

### Details

Currently only asssigning new rows to `ffdf` is supported. The new ffdf rows are not initialized (usually become zero). NOTE that

### Value

The object with a modified dimension

### Author(s)

Jens Oehlschlägel

### See Also

`ffdf`, `dim.ffdf`

### Examples

      a <- as.ff(1:26)
      b <- as.ff(factor(letters)) # vmode="integer"
      c <- as.ff(factor(letters), vmode="ubyte")
      df <- ffdf(a,b,c)
      nrow(df) <- 2*26
      df
      message("NOTE that the new rows have silently the first level 'a' for UNSIGNED vmodes")
      message("NOTE that the new rows have an illegal factor level <0> for SIGNED vmodes")
      message("It is your responsibility to put meaningful content here")
      message("As an example we replace the illegal zeros by NA")
      df$b[27:52] <- NA
      df

      rm(a,b,c,df); gc()

[Package ff version 2.2-13 Index]