Dear list,
 
I have a data frame with one column (group) and want to add a second column (sub) with a serial number that says to which subgroup a cell belongs. A subgroup contains the consecutive rows of the same group. The number of a subgroup is based on its position in the table. The first subgroup of A's and B's should have nr A1 and B1, the second nr A2 and B2, etc.. I hope the example below makes things more clear.
This is what my data look like:
 
x <- read.table(textConnection("group
A
A
A
B    
B
A
A
B 
B
B
A
A"),header=TRUE)
closeAllConnections()
 
   group
1      A
2      A
3      A
4      B
5      B
6      A
7      A
8      B
9      B
10     B
11     A
12     A
 
This is what it should become:
 
   group sub
1      A A1
2      A A1
3      A A1
4      B B1
5      B B1
6      A A2
7      A A2
8      B B2
9      B B2
10     B B2
11     A A3
12     A A3
 
 

 

Maarten Stevens

Senior onderzoeker - Aquatisch Beheer / Senior scientist - Aquatic Management 

 

INBO – Instituut voor Natuur- en Bosonderzoek / Research Institute for Nature and Forest

Afdeling Beheer en Duurzaam Gebruik / Dept. Management and Sustainable Use

Kliniekstraat 25 ź B-1070 Brussels, BELGIUM

E-mail: maarten.stevens@inbo.be <mailto:maarten.stevens@inbo.be> 

Phone: +32.2.558.19.18 ź Gsm / Cell: +32.492.72.28.97 ź Fax: +32.2.558.18.05 ź www.inbo.be <http://www.inbo.be/> 

 

 

 

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