[R] Coercion of percentages by as.numeric

[Brandt, T. (Tobias)]

Hi

Given that things like the following work
 
 > a <- c("-.1"," 2.7 ","B")
> a
[1] "-.1"   " 2.7 " "B"    
> as.numeric(a)
[1] -0.1  2.7   NA
Warning message:
NAs introduced by coercion 
> 

I naively expected that the following would behave differently.
 
 > b <- c('10%', '-20%', '30.0%', '.40%')
> b
[1] "10%"   "-20%"  "30.0%" ".40%" 
> as.numeric(b)
[1] NA NA NA NA
Warning message:
NAs introduced by coercion 
> 

> version
         _              
platform i386-pc-mingw32
arch     i386           
os       mingw32        
system   i386, mingw32  
status                  
major    2              
minor    2.0            
year     2005           
month    10             
day      06             
svn rev  35749          
language R              
> 

Various RSiteSearches with terms like "percentage" and "coercion" yielded
nothing.
 
Does anyone know how to do this elegantly?
 
 
Thanks
 
Tobias Brandt
 
 
P.S. Apologies if this appears on the list twice but I suspect an earlier
post was blocked since it was in html format.


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