[R] Querying a data frame or data.table

[David Winsemius]

On Dec 3, 2010, at 3:44 AM, Michael Bedward wrote:

> Sounds just like the subset function (?)
>
> x <- as.data.frame(matrix(sample(5, 100, rep=TRUE), ncol=10))
> subset(x, )

With data,table:
require(data.table)
 > xd <- as.data.table(x)
 > xd[ V1 > 3 & V2 < 5 , ]
      V1 V2 V3 V4 V5 V6 V7 V8 V9 V10
[1,]  4  2  4  1  2  3  1  3  2   4
[2,]  4  1  2  2  4  2  3  2  4   3
[3,]  5  1  1  5  4  5  4  1  1   3



>
> Michael
>
> On 3 December 2010 19:05, Santosh Srinivas  
> <santosh.srinivas at gmail.com> wrote:
>> Hello Group,
>>
>> Is there an easy way to query a data.frame or data.table (this is
>> fast!) for multiple conditions?
>> I don't want to use a SQL kind of statement.
>>
>> I am looking for something like a subset with multiple conditions.
>>
>> Any tips of the like the binary search methodology used for  
>> data.table
>> would also help.
>>
>> Thanks in advance.
>> S

>

David Winsemius, MD
West Hartford, CT