R help - Apr 2009 - factor issue

Hi,

I have a column which I have to convert from factors to numeric. I am using
the command as.numeric(variable) to do this. But when I convert the numeric
value becomes different from factor . for example.
> class(B)
[1] "factor"
> B
 [1] 180  <NA> 183  175  163  155  <NA> 188  191  160  170  165  152
170
165
[16] 163  160  163  165  <NA>
> as.numeric(B)
 [1] 46 NA 47 42 30 26 NA 49 50 29 37 32 24 37 32 30 29 30 32 NA
Is there a different way to convert factor to respective number ?


also when i try to unclass it i get following output
> unclass(B)
 [1] 46 NA 47 42 30 26 NA 49 50 29 37 32 24 37 32 30 29 30 32 NA
attr(,"levels")
 [1] "102" "104" "107" "109"
"110" "112" "114" "117" "119"
"122" "124" "125"
[13] "127" "129" "130" "132"
"135" "137" "140" "142" "145"
"147" "150" "152"
[25] "153" "155" "157" "159"
"160" "163" "164" "165" "166"
"167" "168" "169"
[37] "170" "171" "172" "173"
"174" "175" "177" "178" "179"
"180" "183" "185"
[49] "188" "191" "193" "196"
"198" "201" "203" "211" "46" 
"48"  "51"  "56"
[61] "58"  "60"  "61"  "63" 
"64"  "65"  "66"  "69"  "71" 
"74"  "76"  "79"
[73] "81"  "84"  "86"  "89" 
"91"  "94"  "97"  "99"  "U"

Any help will be appreciated.

Thanks a lot.
Regards,
Nataraju
GM

-- 
"No relationship is Static .. You either Step up or Step down"

	[[alternative HTML version deleted]]

check the following:

http://cran.r-project.org/doc/FAQ/R-FAQ.html#How-do-I-convert-factors-to-numeric_003f


Best,
Dimitris


Nattu wrote:
> Hi,
> 
> I have a column which I have to convert from factors to numeric. I am using
> the command as.numeric(variable) to do this. But when I convert the numeric
> value becomes different from factor . for example.
> 
>> class(B)
> [1] "factor"
>> B
>  [1] 180  <NA> 183  175  163  155  <NA> 188  191  160  170  165
152  170
> 165
> [16] 163  160  163  165  <NA>
>> as.numeric(B)
>  [1] 46 NA 47 42 30 26 NA 49 50 29 37 32 24 37 32 30 29 30 32 NA
> Is there a different way to convert factor to respective number ?
> 
> 
> also when i try to unclass it i get following output
> 
>> unclass(B)
>  [1] 46 NA 47 42 30 26 NA 49 50 29 37 32 24 37 32 30 29 30 32 NA
> attr(,"levels")
>  [1] "102" "104" "107" "109"
"110" "112" "114" "117" "119"
"122" "124" "125"
> [13] "127" "129" "130" "132"
"135" "137" "140" "142" "145"
"147" "150" "152"
> [25] "153" "155" "157" "159"
"160" "163" "164" "165" "166"
"167" "168" "169"
> [37] "170" "171" "172" "173"
"174" "175" "177" "178" "179"
"180" "183" "185"
> [49] "188" "191" "193" "196"
"198" "201" "203" "211" "46" 
"48"  "51"  "56"
> [61] "58"  "60"  "61"  "63" 
"64"  "65"  "66"  "69"  "71" 
"74"  "76"  "79"
> [73] "81"  "84"  "86"  "89" 
"91"  "94"  "97"  "99"  "U"
> 
> Any help will be appreciated.
> 
> Thanks a lot.
> Regards,
> Nataraju
> GM
> 
-- 
Dimitris Rizopoulos
Assistant Professor
Department of Biostatistics
Erasmus University Medical Center

Address: PO Box 2040, 3000 CA Rotterdam, the Netherlands
Tel: +31/(0)10/7043478
Fax: +31/(0)10/7043014