R help - Jan 2013 - How to delete repeated values in MCMC sampling and get index of unique values?

Dear list,
How do you delete repeated samples?  In MCMC, when your candidate value has
been reject, so you remain on the same point, so you keep that value.

Say I have this toy example,
> c(1,6,6,6,3,5,4,4,2,3,5)
The 6 and 4 are repeated, I only want the index of the non-repeated values.

I thought of using which() and unique(), but that does not give you the
index of the unique values.

Thanks in advance.

Mike

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On 13-01-17 4:50 PM, C W wrote:
> Dear list,
> How do you delete repeated samples?  In MCMC, when your candidate value has
> been reject, so you remain on the same point, so you keep that value.
>
> Say I have this toy example,
>
>> c(1,6,6,6,3,5,4,4,2,3,5)
>
> The 6 and 4 are repeated, I only want the index of the non-repeated values.
>
> I thought of using which() and unique(), but that does not give you the
> index of the unique values.
You could use x[!duplicated(x)] or rle(x)$values, depending on your 
definition of "repeated".  I hope you're aware that you can't
use either
for things like quantiles and moments of the limiting distribution.

 > x <- c(1,6,6,6,3,5,4,4,2,3,5)
 > x[!duplicated(x)]
[1] 1 6 3 5 4 2
 > rle(x)$values
[1] 1 6 3 5 4 2 3 5

Duncan Murdoch

On Jan 17, 2013, at 1:50 PM, C W wrote:
> Dear list,
> How do you delete repeated samples?  In MCMC, when your candidate value has
> been reject, so you remain on the same point, so you keep that value.
> 
> Say I have this toy example,
> 
>> c(1,6,6,6,3,5,4,4,2,3,5)
> c(1,6,6,6,3,5,4,4,2,3,5)[!duplicated(c(1,6,6,6,3,5,4,4,2,3,5))]
[1] 1 6 3 5 4 2
> x <- c(1,6,6,6,3,5,4,4,2,3,5)
> x[!duplicated(x)]
[1] 1 6 3 5 4 2
> !duplicated(x)
 [1]  TRUE  TRUE FALSE FALSE  TRUE  TRUE  TRUE FALSE  TRUE FALSE
FALSE
> which(!duplicated(x))
[1] 1 2 5 6 7 9

> 
> The 6 and 4 are repeated, I only want the index of the non-repeated values.
> 
> I thought of using which() and unique(), but that does not give you the
> index of the unique values.
> 
> Thanks in advance.
> 
> Mike
> 
> 	[[alternative HTML version deleted]]
> 
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