> which(x < 5 & x > 2) [1] 3 4
From the help page for Logical Operators:
?"!"
'&' and '&&' indicate logical AND and '|' and '||' indicate
logical OR. The shorter form performs elementwise comparisons in
much the same way as arithmetic operators. The longer form
evaluates left to right examining only the first element of each
vector. Evaluation proceeds only until the result is determined.
The longer form is appropriate for programming control-flow and
typically preferred in 'if' clauses.Y. C. Tao wrote:
Why the last "which" in the following example doesn't work? Is there a simple way to identify the indices of array elements that meet multiple criteria?
Thanks.
YC Tao
x<-1:10 which(x<5)
[1] 1 2 3 4
which(x>2)
[1] 3 4 5 6 7 8 9 10
which(x<5 && x>2)
numeric(0)
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