Convert factors to numbers

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If you have a vector of factors it is easy to get the factor level; however, I always forget how to extract the factor value. I ran into the answer here.

> x<-factor(c(round(rnorm(10),2),"A","B",NA))
> x
 [1] 1.61  1.12  1.26  0.09  -0.13 0.16  -0.03 -0.1  0.09  -0.47 
 [11] A     B    
Levels: -0.03 0.09 -0.1 -0.13 0.16 -0.47 1.12 1.26 1.61 A B
> as.numeric(x)
 [1]  9  7  8  2  4  5  1  3  2  6 10 11 NA
> as.numeric(levels(x)[x])
 [1]  1.61  1.12  1.26  0.09 -0.13  0.16 -0.03 -0.10  0.09 -0.47    
 [11]   NA    NA   NA
Warning message:
NAs introduced by coercion 

**UPDATE**
And another method mentioned in the comments (that I like better):

> as.numeric(as.character(x))

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