R help - Oct 2009 - repeating values in levels()

Can someone help me understand this results?
> levels(as.factor(miset1$facts_convict))
[1] "1" "1" "2" "3" "4"
"5" "6"

converting to numeric and back doesn't seem to help:
> levels(as.factor(as.numeric(miset1$facts_convict)))
[1] "1" "1" "2" "3" "4"
"5" "6"

It's messing up my ologits. ?Any way to correct this?

Donald Braman wrote:
> 
> Can someone help me understand this results?
> 
>> levels(as.factor(miset1$facts_convict))
> [1] "1" "1" "2" "3" "4"
"5" "6"
> 
> converting to numeric and back doesn't seem to help:
> 
>> levels(as.factor(as.numeric(miset1$facts_convict)))
> [1] "1" "1" "2" "3" "4"
"5" "6"
> 
> It's messing up my ologits. ?Any way to correct this?
> 
> 
If we can't reproduce this, we can't help.
Would suggest that you dig back through the
history of how the offending variable/data frame
was created to see how it could have ended up that
way (which is definitely pathological), and try
to provide us with a reproducible example.

Results of sessionInfo() ?


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Donald Braman wrote:
> Can someone help me understand this results?
> 
>> levels(as.factor(miset1$facts_convict))
> [1] "1" "1" "2" "3" "4"
"5" "6"
Don't know how you got your data that way, but I
wonder if you've done str() on your data after
whatever procedure you used to get to this stage.

Here's one way to get this pathological state:

  set.seed(2)
  x <- sample(5, 15, rep=TRUE)
  y <- factor(x, levels=c(1, 1:5))  ## repeating level "1"
  levels(y)
  [1] "1" "1" "2" "3" "4"
"5"
> 
> converting to numeric and back doesn't seem to help:
> 
>> levels(as.factor(as.numeric(miset1$facts_convict)))
> [1] "1" "1" "2" "3" "4"
"5" "6"
I suspect that miset1$facts_convict is already a factor
[str() would tell you] and that the following comment
from ?factor applies:

"In particular, as.numeric applied to a factor is meaningless ..."

If my guess is correct, you should be able to fix things with

  newy <- factor(y)
  levels(newy)
  [1] "1" "2" "3" "4" "5"


  -Peter Ehlers
> 
> It's messing up my ologits.  Any way to correct this?
> 
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