[R] how to complete this task on data management

[Petr Pikal]

Hi

I am not sure what you really want. If you try to preserve first part 
of your objects just exclude them from operation e.g.

data[-(1:5),] will exclude first five rows from your dataframe.

However it is unclear what you want to do next. Instead of three 
items you want only add one different?

data.frame(x=c(data[(1:5),],6))

or another vector

data.frame(x=c(data[(1:5),],some.other.data))

Following probably too complicated construction tells you which is 
the position of the second value lower then some threshold (in this 
case 3.5) in a vector.

which(diff(cumsum(diff(data<3.5)==1)<2)!=0)+2

HTH
Petr



On 23 Aug 2006 at 11:23, zhijie zhang wrote:

Date sent:      	Wed, 23 Aug 2006 11:23:03 +0800
From:           	"zhijie zhang" <epistat at gmail.com>
To:             	R-help at stat.math.ethz.ch
Subject:        	[R] how to complete this task on data management

> Dear friends,
>  When i clean my dataset , i met a difficulty
>  suppose my data set is :
> *> data<-data.frame(x=c(1:5,1,2,3))
> > data
>   x
> 1 1
> 2 2
> 3 3
> 4 4
> 5 5*
> 6 1
> 7 2
> 8 3
> Now i need to add the data which are less than 3.5 at the bottom, not
> including the top data, so the results should be :
>   x
> 1 1
> 2 2
> 3 3
> 4 4
> 5 5
> *6 6*
> I tried to use " data[data$x>3.5,]" to do it , but it also delete the
> first several numbers,* How to finish it ?* Thanks very much. -- Kind
> Regards, Zhi Jie,Zhang
> 
>  [[alternative HTML version deleted]]
> 
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Petr Pikal
petr.pikal at precheza.cz