[R] nrow()

[Sandra Stankowski]

Thanks.
I made it!

Best wishes,
S.



Am 22.02.2011 17:41, schrieb Erik Iverson:
>
>
> Sandra Stankowski wrote:
>> is.na function does'nt seem to work, but maybe I'm just dealing with 
>> it in a wrong way.
>>
>> here's an example
>>
>> > m <- c(2, 3, 5, 6, 3, 7, -99, -99, 6)
>> > n <- c(1,1,1,1,1,2,2,2,2)
>>
>> so my matrix contains certain missing values
>
> Thank you for the example.
> You're constructing a data.frame, not a matrix.
> Those are two separate classes in R.
>
>> > m[m==-99] <- NA
>> > o <- data.frame(m, n)
>> > o
>>    m n
>> 1  2 1
>> 2  3 1
>> 3  5 1
>> 4  6 1
>> 5  3 1
>> 6  7 2
>> 7 NA 2
>> 8 NA 2
>> 9  6 2
>>
>> "2" stands for february
>>
>> > february <- which(o[,2]==2, arr.ind = TRUE)
>> > prec_feb <- sum(o[february,1], na.rm = TRUE)
>> > prec_feb
>> [1] 13
>>
>> And now I need to know the exact number of rows, where "m"  contains 
>> a value. to know how many days a month give any information. (to 
>> create monthly means and stuff)
>
> You might find ?complete.cases useful.
>
> Also try:
>
> sum(!is.na(o$m))
>
> ?tapply may also be useful in general: e.g.,
>
> tapply(o$m, o$n, mean, na.rm  = TRUE)
>
> None of this is tested...
>
>>
>> hope this explains, what I need to know.
>>
>> Thanks,
>> S.
>>
>>
>>
>>
>>
>> Am 22.02.2011 16:50, schrieb Erik Iverson:
>>> Sandra,
>>>
>>> Please provide a small, reproducible example of this issue.
>>> You probably want to use ?is.nan and not the inequality
>>> operator.
>>>
>>> Similar example, contrast:
>>>
>>> x <- NA
>>> is.na(x)
>>> x == NA
>>>
>>> Sandra Stankowski wrote:
>>>> Hey there,
>>>>
>>>> I tried to count the number of rows, where my data isn't NaN in a 
>>>> certain column.
>>>>
>>>> this was my guess:
>>>>
>>>> (given is a data frame with 2069 rows and 17 cols)
>>>>
>>>> NROW(data[jan,16] != NaN)
>>>>
>>>> ("jan" is defined this way: jan <- which(data[,2]==1, arr.ind= TRUE))
>>>>
>>>>
>>>> but I only get the number of columns where my data is "1" in the 
>>>> second col. R isn't removing the NaN.
>>>> na.rm isn't working here.
>>>>
>>>> I would appreciate your help.
>>>>
>>>> ______________________________________________
>>>> 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.
>>>
>>
>