Rolf Turner wrote:
>
> On 22/04/2009, at 8:34 AM, Crosby, Jacy R wrote:
>
>> How can I delete both rows and columns that do not meet a particular
>> cut off value.
>> Example:
>>> d <- rbind(c(0, 1, 6, 4),
>> + c(2, 5, 7, 5),
>> + c(3, 6, 1, 6),
>> + c(4, 4, 4, 4))
>>> f <- as.matrix(d)
>>> f
>> [,1] [,2] [,3] [,4]
>> [1,] 0 1 6 4
>> [2,] 2 5 7 5
>> [3,] 3 6 1 6
>> [4,] 4 4 4 4
>>
>> I would like to delete all rows and columns that do not contain at
>> least one element with a value less than 1.
>
> Apparently you actually want ``less than or equal to 1''.
>
>> So I'd end up with:
>>
>>> f
>> [,1] [,2] [,3]
>> [1,] 0 1 6
>> [3,] 3 6 1
>>
>> Note: 1 is an arbitrary cut-off value.
>
> d[apply(d,1,function(x){any(x<=1)}),apply(d,2,function(x){any(x<=1)})]
... or gain a bit on performance by doing the threshold comparison on
the whole matrix just once at once:
dd = d <= 1
d[apply(d, 1, any), apply(d, 2, any)]
vQ
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