Do this in a single pass?

while(i < bArray.length)
  if(aArray.include?(bArray[i]) == false) then
    return false
  end
  i+=1
end

I've written the above but I find it to be ugly and bloated. There must be a clean cut开发者_StackOverflow社区 way to do this in a single statement.. but how?

This should be equivalent:

while i < bArray.length
  return false unless aArray.include?(bArray[i])

  i += 1
end

Here's a one-liner that I think should be equivalent:

bArray.all? { |item| aArray.include?(item) }

It looks like you're trying to find out if aArray contains all the elements of bArray.

aArray = %w[a b c d]
bArray = %w[a b c z]

(bArray - aArray).empty? # => false

I looked at the original code closer and it's got a logic bomb ticking:

def cmp_array(aArray, bArray)
  i = 0
  while (i < bArray.length)
    if (aArray.include?(bArray[i]) == false) then
      return false
    end
    i += 1
  end
end

def cmp_array2(a, b)
  (b - a).empty?
end

cmp_array( %w[ a b c ], %w[ a b c   ]) # => nil
cmp_array( %w[ a b c ], %w[ c b a   ]) # => nil
cmp_array( %w[ a b c ], %w[ a b     ]) # => nil
cmp_array( %w[ a b c ], %w[ a b c d ]) # => false
cmp_array( %w[ a b   ], %w[ a b c   ]) # => false

cmp_array2( %w[ a b c ], %w[ a b c   ]) # => true
cmp_array2( %w[ a b c ], %w[ c b a   ]) # => true
cmp_array2( %w[ a b c ], %w[ a b     ]) # => true
cmp_array2( %w[ a b c ], %w[ a b c d ]) # => false
cmp_array2( %w[ a b   ], %w[ a b c   ]) # => false

I had to add the i = 0 initializer otherwise Ruby complained about the uninitialized variable.

Notice that cmp_array returns either nil or false, forcing an additional test for nil? or false? to do something useful.

if (cmp_array( %w[ a b c ], %w[ a b c   ]).nil?) ...

or:

if (cmp_array( %w[ a b c ], %w[ a b c d ]).false?) ...

compared to:

if (cmp_array2( %w[ a b c ], %w[ a b c   ])) ...

which consistently returns true/false.

bArray.all?(&aArray.method(:include?))