[Rd] Use logical expresion on ff object

Krystian Radlak radler12 at op.pl
Thu Aug 18 11:09:59 CEST 2011


I want to do operation with ff vector from packages ff like simple operation
in R like this. (I have read data from file)
Example 
a=1:10
b=a[a>5]

how to do this operation with ff packages:
Example :
a=ff(1, length=15*10^7)

I know that I could get logical vector like this:

k=bit(15*10^7) # from bit packages
a=ff(-1,15*10^7)
system.time(
		for (i in chunk(a)){ k[i]<- a[i]<1}
)

Any suggestions?

Best,
Krystian



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