[R] dates are shown as X15.Feb.03

[Duncan Murdoch]

On 9/27/2005 12:13 PM, Chris Buddenhagen wrote:
> Dear Duncan Murdoch
> 
> Thanks for responding. I will provide more complete info with future
> questions. The data for a small pilot study are below. 
> 
> The values for each month are the percentage cover of an invasive plant here
> in the Galapagos (TT=treatment) type = immediately herbicide applied or
> applied to regrowth later. I called the data glyphosate.txt.
> 
> 
> The code is
> 
> glyp<-read.delim("C:\\Chris\\active projects\\Aristolochia\\glyphosate.txt",
> header=T)
> list(names(glyp))
> 
> This is the output that mystified me:
> 
> [1] "TT"         "type"       "CUADRANTES" "X15dec02"   "X15jan03"  
>  [6] "X15feb03"   "X15apr03"   "X15jun03"   "X15aug03"   "X15oct03"

It looks as though you have column headings like "15dec02".  That's not 
a legal R variable name, so it prepends the X to make it into one.  That 
way you can do things like glyp$X15dec02 to extract that column. 
glyp$15dec02 would give a syntax error.


> 
> While I have an expert on hand I have another question, how do I produce a
> graph of time against percentage cover with error bars. I wanted to only
> present months on the x axis. I start by reorganizing the data using this:

Various functions implement error bars, but I haven't used them in a 
long  time, so I'll leave this question for someone else to answer.

Duncan Murdoch

> 
> glyp2<-reshape(glyp, direction="long", idvar=c("TT", "type",
> "CUADRANTES"),varying=list(names(glyp)[4:10]),v.names="cover") but couldn't
> get month names to appear in the column time.
> 
> 
> 
> TT	type	CUADRANTES	"15dec02"	"15jan03"	"15feb03"
> "15apr03"	"15jun03"	"15aug03"	"15oct03"
> T1	immediate	1	63	59	60	55	4.5	1
> 2
> T1	immediate	2	75	75	75	75	6.5	1
> 2
> T1	immediate	22	72	70	70	65	35	2
> 3.5
> T1	immediate	26	90	80	80	75	17.5	2
> 4
> T1	immediate	33	75	80	85	85	40	1
> 2
> T2	immediate	18	85	80	80	22.5	2.5	2
> 5
> T2	immediate	21	90	85	85	60	16.5	0
> 1
> T2	immediate	23	85	80	80	75	17.5	1
> 2
> T2	immediate	28	90	85	85	27.5	27.5	0
> 1
> T2	immediate	31	90	85	85	9	12.5	1
> 2
> T3	immediate	3	50	58	60	65	35	1
> 2
> T3	immediate	10	63	60	60	15	2.5	0
> 10
> T3	immediate	12	90	85	85	17.5	15	0
> 5
> T3	immediate	16	85	82	80	78	9	1
> 1.5
> T3	immediate	34	75	80	85	85	35	1.5
> 2.5
> T4	wait	4	75	75	75	7.5	2.5	0	0
> T4	wait	11	63	60	60	12.5	2.5	1	2
> T4	wait	24	90	85	80	3.5	5.5	1	2
> T4	wait	29	85	80	80	1.5	4.5	1	2
> T4	wait	32	85	80	80	3.5	4.5	2	3.5
> T5	wait	6	50	50	50	1	1	0.5	2
> T5	wait	14	80	75	75	15	5.5	1	2
> T5	wait	15	90	80	80	1	5.5	1	3
> T5	wait	20	85	80	80	22.5	8.5	0	0
> T5	wait	25	85	80	80	22.5	8.5	1	1.5
> T6	wait	8	75	75	75	1.5	4.5	0	1.5
> T6	wait	9	90	85	85	1.5	3.5	1	2
> T6	wait	13	80	75	75	1	3.5	1	1.5
> T6	wait	19	90	85	80	1	2.5	1	2
> T6	wait	27	85	80	75	1	3.5	1	2
> Tc	control	5	50	45	45	40	23	20	25
> Tc	control	7	50	53	54	55	55	50	55
> Tc	control	17	90	80	70	22.5	9	15	20
> Tc	control	30	75	75	70	75	45	60	70
> Tc	control	35	90	85	80	85	65	60	70
> 
> Chris Buddenhagen, Botany Department, Charles Darwin Research Station, Santa
> Cruz,Galapagos. Mail: Charles Darwin Foundation, Casilla 17-01-3891 Avenida
> 6 de Diciembre N36-109 y Pasaje California Quito, ECUADOR
>  
> 
> 
> 
> 
> 
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