R help - Feb 2007 - exact matching of names in attr

In R 2.5.0 (r40806), one of the change is to allow partial matching of 
"name" in the attr function. However, how can I tell if I have an
exact
match or not?

For example, checking to see if an object has a "name" attribute, then
giving it one if it doesn't:

dat <- data.frame(x=1:10,y=rnorm(10))
if(is.null(attr(dat,"name")))
    attr(dat,"name") <- "Site 1"
str(dat)

(This example works in R < 2.5) Although there is no "name"
attribute to
the data.frame, it partially matches to "names", resulting in not 
setting the attribute. (Personally, I think this change in the "attr" 
function is not desirable, and much prefer exact matches to avoid 
unintentional errors).

How can I tell if this is an exact match? Is there a way to force an 
exact match?

Thanks.

+mt

if (!"name" %in% names(attributes(dat))) {
  ...
}

/Henrik

On 2/26/07, Michael Toews <mwtoews at sfu.ca>
wrote:
> In R 2.5.0 (r40806), one of the change is to allow partial matching of
> "name" in the attr function. However, how can I tell if I have an
exact
> match or not?
>
> For example, checking to see if an object has a "name" attribute,
then
> giving it one if it doesn't:
>
> dat <- data.frame(x=1:10,y=rnorm(10))
> if(is.null(attr(dat,"name")))
>     attr(dat,"name") <- "Site 1"
> str(dat)
>
> (This example works in R < 2.5) Although there is no "name"
attribute to
> the data.frame, it partially matches to "names", resulting in not
> setting the attribute. (Personally, I think this change in the
"attr"
> function is not desirable, and much prefer exact matches to avoid
> unintentional errors).
>
> How can I tell if this is an exact match? Is there a way to force an
> exact match?
>
> Thanks.
>
> +mt
>
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