Comparing Arrays
in [Ruby]
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From: Derek Cannon on 12 Apr 2010 01:49 Hello everyone, another easy question from a beginner: How do you create a method to compare two arrays so that if they share at least 1 common element it returns true? For example: a = %w(m w f) b = %w(m w) c = %w(t r) share_elements?(a,b) #=> true share_elements?(a,c) #=> false Thanks for your time, Derek -- Posted via http://www.ruby-forum.com/.
From: Jean-Julien Fleck on 12 Apr 2010 02:17 Hello Derek, 2010/4/12 Derek Cannon <novellterminator(a)gmail.com>: > Hello everyone, another easy question from a beginner: How do you create > a method to compare two arrays so that if they share at least 1 common > element it returns true? Well, you could use exactly the have_common? method I provided to compare ranges because arrays also have a to_a method (that does nothing else than returning the array itself) def have_common?(r1,r2) arr = r1.to_a & r2.to_a !arr.empty? end a = %w(m w f) b = %w(m w) c = %w(t r) have_common?(a,b) have_common?(a,c) Cheers, -- JJ Fleck PCSI1 Lycée Kléber
From: Derek Cannon on 12 Apr 2010 02:25 Thanks Jean, this is the first thing I tried, but I accidentally used the word "and" instead of &. What's the difference between & and "and" in this case? -- Posted via http://www.ruby-forum.com/.
From: GianFranco Bozzetti on 12 Apr 2010 02:50 "Derek Cannon" <novellterminator(a)gmail.com> wrote in message news:24f32d608e99f3ef93bca701fdfe130c(a)ruby-forum.com... > Hello everyone, another easy question from a beginner: How do you create > a method to compare two arrays so that if they share at least 1 common > element it returns true? > > For example: > a = %w(m w f) > b = %w(m w) > c = %w(t r) > > share_elements?(a,b) #=> true > share_elements?(a,c) #=> false > > Thanks for your time, > Derek > -- > Posted via http://www.ruby-forum.com/. > An answer: # array_cmp.rb def share_elements?(a1,a2) not (a1 & a2).empty? end a = %w(m w f) b = %w(m w) c = %w(t r) r = share_elements?(a,b) #=> true printf("%12s/%-12s => %s\n", a.inspect.to_s, b.inspect.to_s, r.to_s) r = share_elements?(a,c) #=> false printf("%12s/%-12s => %s\n", a.inspect.to_s, c.inspect.to_s, r.to_s) exit(0) Hth gfb
From: Priyanka Pathak on 12 Apr 2010 02:50
Hi, "&" is bitwise operator. "and" is logical operator & for composition. that's main difference between "&" and "and". so, as you need to compare array element use &. -- Posted via http://www.ruby-forum.com/. |