Greetings All.
Once again, I am probably missing something fairly accessible,
but since I can't find it I'd welcome advice!
I have a dataframe derived from a text file of data in tabular
format. For one of the variables, say X, I want to select the
subsets which in which X equals a particular
Hello,
Like this?
equals - function(x, y, tol = .Machine$double.eps^0.5) abs(x - y) tol
x - rnorm(5)
y - x[2]
equals(x, y)
[1] FALSE TRUE FALSE FALSE FALSE
y - rnorm(3)
y[2] - x[2]
equals(x, y)
[1] FALSE TRUE FALSE FALSE FALSE
Warning message:
In x - y : longer object length is not a
Thanks, Rui, but that was not my (apparently implicit) question.
Apologies if my wording gave the wrong impression. I was really
asking if such a function was already available somewhere in R.
Yes, your definition of equals() is one possibility; or, with the
work-round I was using,
equals -
Hello,
The two approaches are conceptually different. With yours we get
equality given a certain number of (significant) digits, which might be
what you are looking for if the measurements are known to be made with
those digits, a frequent case.
And there's also Bert's Vectorize way, with
Yes, Rui's suggestion is what I would do, too.
However, for fun, here is a different, way less efficient, but perhaps
instructive (or amusing?) alternative using Vectorize() and all.equal()
directly:
foo - function(target,current,...)isTRUE(all.equal(target,current,...))
equals -
Hi Rui:
Good points. However, as my offering is, I think, little more than a
disguised loop -- as compared to yours' and Ted's truly vectorized
solutions --I think it is far too inefficient to useful. I offered it
merely for its aesthetic interest, which is what you noted in your
comments below.
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