How to split two levels several times?

Hi
this type of splitting works for my specific example. Thanks for your help.

I was not absolutely clear what I generally want. I'm looking for an option that generally permits splitting two joint levels of a table after each other. For instance for the table below I want it to be divided into combinations electrode1-electrode2,  electrode3-electrode2,  electrode4-electrode1. How should I split this?


This is the table "XXX"

electrode length

electrode1 5.7
electrode1 6.3
electrode1 6.2
electrode2 11.4
electrode2 9.7
electrode3 14.2
electrode3 14.8
electrode3 12.6
electrode2 11.4
electrode2 9.7
electrode4 17.0
electrode4 16.3
electrode4 17.8
electrode4 18.3
electrode4 16.9
electrode4 18.5
electrode1 5.7
electrode1 6.3
electrode1 6.2

Gesendet: Montag, 22. Juli 2013 um 17:53 Uhr
Von: "Rui Barradas" <ruipbarradas at sapo.pt>
An: dennis1991 at gmx.net
Cc: r-help at r-project.org
Betreff: Re: [R] How to split two levels several times?

Hello,

Sorry, I've just realized that your data frame is named 'XXX', not
'dat'. Change that and the rest should work:


idx <- cumsum(c(TRUE, diff(XXX$electrode == "electrode1") > 0))
split(XXX, idx)


Rui Barradas

Em 22-07-2013 16:47, Rui Barradas escreveu:

Hello,

Try the following.


idx <- cumsum(c(TRUE, diff(dat$electrode == "electrode1") > 0))
split(dat, idx)


Hope this helps,

Rui Barradas

Em 22-07-2013 15:09, dennis1991 at gmx.net escreveu:

Hi,

I have a small problem with the function split() and would appreciate
your help.

I have a table called ?XXX? with 2 columns and 49 rows. The 49 rows
belong to 8 different levels (electrode1, ...,electrode8). I want to
split the table always at the row where ?electrode1? starts again so
that I can export 7  individual dataframes (numbered ?dataframe1? to
?dataframe7?) which contain always electrode1 as first level (always
three rows) with the varying number of rows for electrodes2-8 below.
I tried the split function with various setups:

t <- as.factor(XXX$electrode)

dataframeX <- split(XXX, f=(levels=t))

But this doesn?t work. Could you please help. Thank you! Dennis


This is the table "XXX"

electrode    length

electrode1    5.7
electrode1    6.3
electrode1    6.2
electrode2    11.4
electrode2    9.7
electrode1    5.7
electrode1    6.3
electrode1    6.2
electrode3    14.2
electrode3    14.8
electrode3    12.6
electrode1    5.7
electrode1    6.3
electrode1    6.2
electrode4    17.0
electrode4    16.3
electrode4    17.8
electrode4    18.3
electrode4    16.9
electrode4    18.5
electrode1    ....
....        ....
electrode5    ....
....        ....
electrode1    ....
electrode6    ....
electrode1    ....
electrode7    ....
electrode1    ....
electrode8    ....