From: 7stud -- <dolgun@...>
Date: 2007-10-03T21:50:26+09:00
Subject: Re: Searching through a sorted array

Axel Etzold wrote:
> 
> # some example
> len=10**8
> a=(1..len).to_a
> b=5*len/2
> cond='lower_index>10'
> r=a.find_lower_index(cond)
> cond='upper_index<100'
> s=a.find_upper_index(cond)
> p r,s
> p a[r]
> p a[s]

When I use this code:

a = [2, 4, 6, 8]
cond='lower_index>0'
r=a.find_lower_index(cond)
cond='upper_index<2'
s=a.find_upper_index(cond)
p r,s
p a[r]
p a[s]

I get this output:

3
1
8
4

The output appears to be backwards, since the lower index would be 1 and 
the upper index would be 3.  And it's a little bit puzzling why a search 
would be needed to find an index in an array that is greater than 0.  I 
can tell you the answer without searching: it's 1.  The same goes for 
the upper index: if the cond = "upper index < 2", then the upper index 
is 1.
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