Your task is to find the number couple with the greatest difference from a given array of number-couples. 

All number couples will be given as strings and all numbers in them will be positive integers.  

For instance: ['56-23','1-100']; in this case, you should identify '1-100' as the number couple with the greatest difference and return it.

In case there are more than one option, for instance ['1-3','5-7','2-3'], you should identify whichever is first, so in this case '1-3'. 

If there is no difference, like so ['11-11', '344-344'], return false.

Source: codewars | Difficulty: EASY
Tags: Fundamentals

Starter code: def diff(arr):
	

Solutions:
def diff(arr):
	r = arr and max(arr, key=lambda x: abs(eval(x)))
	return bool(arr and eval(r)) and r


def diff(arr):
	r = [abs(eval(s)) for s in arr]
	return arr[r.index(max(r))] if r and max(r) else False


def diff(arr):
	r = [abs(int(w.split('-')[0]) - int(w.split('-')[1])) for w in arr]
	return arr[r.index(max(r))] if sum(r) else False


def diff(arr):
	if not arr:
		return 0
	m = max(arr, key=lambda x: abs(eval(x)))
	return eval(m) and m


def difference(x):
	(a, b) = map(int, x.split('-'))
	return abs(a - b)

def diff(arr):
	if not arr:
		return False
	x = max(arr, key=difference)
	if difference(x) == 0:
		return False
	return x


def diff(pairs):
	max_diff = max_pair = 0
	for pair in pairs:
		(a, b) = pair.split('-')
		current = abs(int(a) - int(b))
		if current > max_diff:
			max_diff = current
			max_pair = pair
	return max_pair


def diff(arr):
	vals = [abs(eval(pair)) for pair in arr]
	return False if all((val == 0 for val in vals)) else arr[vals.index(max(vals))]
	return val


def diff(arr):
	z = {}
	for i in range(0, len(arr)):
		s = arr[i].split('-')
		d = abs(int(s[0]) - int(s[1]))
		z.update({arr[i]: d})
	w = {k: v for (k, v) in sorted(list(z.items()), reverse=True, key=lambda x: x[1])}
	if w == {} or max(w.values()) == 0:
		return False
	else:
		return max(w, key=w.get)


def diff(arr):
	diff = []
	if arr == []:
		return False
	for i in range(len(arr)):
		str = arr[i].split('-')
		diff.append(abs(int(str[1]) - int(str[0])))
	if max(diff) == 0:
		return False
	for j in range(len(arr)):
		if diff[j] == max(diff):
			return arr[j]


def diff(arr):
	if not arr:
		return False

	def cust_key(s):
		(a, b) = map(int, s.split('-'))
		return abs(a - b)
	m = max(arr, key=cust_key)
	return m if len(set(m.split('-'))) == 2 else False