[R] delete data row

[Joshua Wiley]

Jim and David,

I certainly agree with your suggestions.  How would you implement
all.equal()?  Since it compares entire objects (and the OP's goal is
to remove any rows that equal some value), the only option I saw was
to use *apply or a loop.  zapsmall() is easier, (though it seems
potentially slow if the data frame is very large). A toy example with
some attempts I made follow:

x <- c(1, 2, 3, 5, 2, 3, 1)
y <- 2

# Using calling all.equal on each element of x
x[-which(as.logical(sapply(x, all.equal, current = y)))]
# A crude introduction of tolerance
x[-which(x <= y + .00001 & x >= y - .00001)]
# Using zapsmall
x[-which(zapsmall(x) == zapsmall(y))]

Cheers,

Josh

On Sat, Oct 16, 2010 at 12:12 PM, David Winsemius
<dwinsemius at comcast.net> wrote:
>
> IRD;
>
> There is a danger in applying logical tests of equality to floating point
> numbers. It may be safer to use all.equal or zapsmall in the construction of
> your tests.
>
>> all.equal( (2^(0.5))^2 , 2)
> [1] TRUE
>> (2^(0.5))^2 == 2
> [1] FALSE
>
>
> --
> David.
>
> On Oct 16, 2010, at 1:30 PM, Joshua Wiley wrote:
>
>> Dear IRD,
>>
>> One way is to select every row except those where y = y.j and then
>> assign that to IR.  In my example, which() returns a vector of the row
>> numbers where the condition evaluated TRUE, then I used `-` to select
>> not those rows.
>>
>> IR <- IR[-which(IR$y == y.j), ]
>>
>> HTH,
>>
>> Josh
>>
>> On Sat, Oct 16, 2010 at 5:02 AM, IRD <ird_ubru at hotmail.com> wrote:
>>>
>>>  Dear All
>>> I have data like this:
>>>>
>>>> IR
>>>
>>>     x        y
>>> [1,] 5 2.865490
>>> [2,] 3 1.454611
>>> [3,] 3 2.258772
>>> [4,] 6 1.476128
>>> [5,] 4 2.771606
>>>>
>>>> y.j
>>>
>>>      y
>>> 2.865490
>>>>
>>> and I want to delete data row in IR where y = y.j
>>> How I can do.
>>> IRD
>>>
>>> ______________________________________________
>>> R-help at r-project.org mailing list
>>> https://stat.ethz.ch/mailman/listinfo/r-help
>>> PLEASE do read the posting guide
>>> http://www.R-project.org/posting-guide.html
>>> and provide commented, minimal, self-contained, reproducible code.
>>>
>>
>>
>>
>> --
>> Joshua Wiley
>> Ph.D. Student, Health Psychology
>> University of California, Los Angeles
>> http://www.joshuawiley.com/
>>
>> ______________________________________________
>> R-help at r-project.org mailing list
>> https://stat.ethz.ch/mailman/listinfo/r-help
>> PLEASE do read the posting guide
>> http://www.R-project.org/posting-guide.html
>> and provide commented, minimal, self-contained, reproducible code.
>
>



-- 
Joshua Wiley
Ph.D. Student, Health Psychology
University of California, Los Angeles
http://www.joshuawiley.com/