David,
I struggled with this for a while. I think the problem with the dates
I have is that they are not specific dates, they are "partial" dates.
A workaround for that that I got from someone else in the list was:
as.Date(paste(x$Date, '1'), '%B %Y %d')
to make them specific dates (the first of the month).
Cheers,
-Oscar
On Mar 10, 2009, at 7:58 PM, David Winsemius wrote:
You need to convert W$Date into a real date variable. At the moment
it is just a character variable.
> str(W)
'data.frame': 265 obs. of 23 variables:
$ Date : Factor w/ 265 levels " ","April 1987",..: 1 90
68 156 2 178 134 ...
$ AZ.Phoenix : Factor w/ 236 levels "","100.00","100.43",..:
236 1 1 1 1 1 1 1 1 1 ...
$ CA.Los.Angeles : Factor w/ 260 levels "100.00","100.02",..: 260
113 114 115 116 ...
$ CA.San.Diego : Factor w/ 261 levels "100.00","101.07",..: 261
109 110 111 112 ...
$ CA.San.Francisco: Factor w/ 256 levels "100.00","102.70",..: 256
108 109 110 111 ...
.(output trimmed)
.
.
?Date # not the variable name, the R class name
?format.Date
?strptime
Unfortunately I seem to be at one of the many limits to my knowledge:
This code behaves in the manner I expected:
> format(Sys.time(), "%a %b %d %X %Y %Z")
[1] "Tue Mar 10 22:19:28 2009 EDT"
> strptime(format(Sys.time(), "%a %b %d %X %Y %Z"), format="%a %b %d
%X %Y %Z")
[1] "2009-03-10 22:20:04"
Whereas this code does not:
> format(Sys.Date(), "%B %Y")
[1] "March 2009"
> as.Date(format(Sys.Date(), "%B %Y"), "%B %Y")
# would have assumed one was the inverse of the other, but ...
[1] NA
For some reason I cannot get the space delimited Month-YYYY combo to
convert. I can getother space delimited formats to work for input
or output:
> as.Date("03 1998", "%M %Y")
[1] "1998-03-10"
> format(Sys.Date(), "%B %Y")
[1] "March 2009"
Puzzled;
--
David Winsemius
On Mar 10, 2009, at 9:15 PM, Oscar Bonilla wrote:
Hi,
I am trying to plot the Case-Shiller index found at:
http://www2.standardandpoors.com/spf/pdf/index/CSHomePrice_History_022445.xls
The way I'm importing it into R is as follows:
library(gdata)
W <- read.xls("http://www2.standardandpoors.com/spf/pdf/index/CSHomePrice_History_022445.xls
", header=TRUE)
attach(W)
To give you and idea of what the data looks like:
> head(W)
Date AZ.Phoenix CA.Los.Angeles CA.San.Diego CA.San.Francisco
1 PHXR LXXR SDXR
SFXR
2 January 1987 59.33 54.67
46.61
3 February 1987 59.65 54.89
46.87
4 March 1987 59.99 55.16
47.32
5 April 1987 60.81 55.85
47.69
6 May 1987 61.67 56.35
48.31
CO.Denver DC.Washington FL.Miami FL.Tampa GA.Atlanta IL.Chicago
MA.Boston
1 DNXR WDXR MIXR TPXR ATXR
CHXR BOXR
2 50.20 64.11 68.50 77.33
53.55 70.04
3 49.96 64.77 68.76 77.93
54.64 70.08
4 50.15 65.71 69.23 77.76
54.80 70.00
5 50.55 66.40 69.20 77.56
54.88 70.70
6 50.63 67.27 69.46 77.85
55.43 71.51
MI.Detroit MN.Minneapolis NC.Charlotte NV.Las.Vegas NY.New.York
OH.Cleveland
1 DEXR MNXR CRXR LVXR
NYXR CEXR
2 63.39 66.36
74.42 53.53
3 63.94 67.03
75.43 53.50
4 64.17 67.34
76.25 53.68
5 64.81 67.88
77.34 53.75
6 65.18 67.90
79.16 54.71
OR.Portland TX.Dallas WA.Seattle Composite.10 Composite.20
1 POXR DAXR SEXR CSXR SPCS20R
2 41.05 62.82
3 41.28 63.39
4 41.06 63.87
5 40.96 64.57
6 41.24 65.56
Now on to the problem... if I just run
plot(CA.San.Francisco ~ Date)
I get:
<pastedGraphic.png>
Which I suspect is a problem because the Date column is not really
a Date, it is a "factor"
> class(Date)
[1] "factor"
If I run:
plot(as.numeric(CA.San.Francisco), type="l")
I get:
<pastedGraphic.png>
which is wrong, as CA.San.Francisco has no such discontinuity.
> CA.San.Francisco
[1] SFXR 46.61 46.87 47.32 47.69 48.31 48.83 49.49 49.94
50.69
[11] 51.33 51.80 52.03 52.24 52.64 53.19 54.19 56.09 58.22
58.70
[21] 59.00 59.50 60.37 61.31 62.20 62.66 63.32 64.64 66.27
67.77
[31] 69.26 70.27 71.36 72.31 72.95 73.25 73.02 72.87 72.95
73.50
[41] 74.57 75.12 75.15 74.81 74.45 74.24 73.44 72.58 71.47
71.17
[51] 70.27 69.56 69.46 70.13 70.83 71.39 71.52 71.55 71.21
70.69
[61] 70.05 69.67 69.48 69.17 69.26 69.86 70.02 70.00 69.64
69.51
[71] 69.28 68.85 68.21 67.77 67.44 67.09 67.59 67.90 67.99
67.65
[81] 67.63 67.50 67.18 66.77 66.27 65.98 65.79 66.37 67.05
67.70
[91] 68.15 68.38 68.40 68.21 68.17 68.04 67.93 67.73 67.40
66.79
[101] 67.08 67.31 67.50 67.72 67.78 67.76 67.30 66.80
66.43 66.15
[111] 65.97 65.92 66.44 67.05 67.67 68.02 68.35 68.43
68.53 68.72
[121] 68.69 68.80 68.81 69.78 71.09 72.19 73.12 73.75
74.43 74.76
[131] 75.22 75.31 75.81 76.19 76.53 77.48 79.08 80.82
82.41 83.52
[141] 84.41 85.06 85.05 84.66 84.50 85.03 85.93 87.51
89.21 90.82
[151] 92.52 94.20 95.14 96.15 96.72 97.87 98.90 100.00
102.70 106.56
[161] 110.97 115.01 118.45 119.48 119.95 120.94 123.08 125.66
128.58 131.16
[171] 133.27 134.10 134.38 134.09 132.64 130.95 129.15 128.60
128.01 126.99
[181] 125.47 125.13 126.06 128.79 132.62 136.07 139.35 141.02
141.93 142.29
[191] 142.74 143.06 142.40 141.90 142.19 143.00 144.69 145.53
146.53 147.75
[201] 148.72 150.25 151.75 153.36 154.62 155.93 158.11 160.90
164.65 167.76
[211] 171.51 173.85 175.89 178.15 180.75 183.15 185.72 189.35
193.50 198.30
[221] 201.86 205.52 208.92 211.56 212.86 214.73 215.55 215.70
215.11 214.78
[231] 215.50 216.04 217.52 218.37 218.12 217.63 217.22 216.37
215.42 213.84
[241] 212.13 211.78 210.78 211.09 211.47 210.89 209.48 208.64
208.15 206.46
[251] 202.03 195.49 189.23 183.81 174.54 168.38 164.63 162.70
159.83 156.88
[261] 151.42 145.53 139.44 135.28 130.12
256 Levels: 100.00 102.70 106.56 110.97 115.01 118.45 119.48
119.95 ... SFXR
However, as.numeric(CA.San.Francisco) does have it!
> as.numeric(CA.San.Francisco)
[1] 256 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122
123 124
[19] 125 126 127 128 129 130 131 132 133 134 140 164 185 199 205
211 214 217
[37] 215 213 214 219 224 227 228 226 223 221 218 212 207 203 199
190 187 198
[55] 201 206 208 209 204 200 197 192 188 184 185 194 196 195 191
189 186 183
[73] 173 164 154 149 156 166 168 158 157 155 150 144 140 138 135
141 147 160
[91] 171 175 176 173 172 170 167 162 153 145 148 152 155 161 165
163 151 146
[109] 142 139 137 136 143 147 159 169 174 177 178 180 179 181 182
193 202 210
[127] 216 220 222 225 229 230 231 232 233 234 235 236 237 238 239
244 243 241
[145] 240 242 245 246 247 248 249 250 251 252 253 254 255 1 2
3 4 5
[163] 6 7 8 9 10 13 17 23 26 28 29 27 25 22 20
18 16 15
[181] 12 11 14 19 24 31 32 34 36 38 40 42 39 35 37
41 43 44
[199] 45 46 47 48 50 51 52 53 55 57 60 61 63 64 66
67 68 69
[217] 71 73 74 76 77 79 83 89 92 94 99 100 96 95 98
101 104 107
[235] 106 105 103 102 97 93 91 90 85 87 88 86 84 82 81
80 78 75
[253] 72 70 65 62 59 58 56 54 49 44 33 30 21
What I'd like to get, is a graph like this (the red line):
<pastedGraphic.png>
I'm really puzzled about what's going on here. Any help would be
greatly appreciated.
Thanks,
-Oscar
______________________________________________
R-help@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.
David Winsemius, MD
Heritage Laboratories
West Hartford, CT
______________________________________________
R-help@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.
