I am trying to write a code that takes

• m. a, a list of integers

• n. b, an integer and returns the number of pairs (m,n) with m,n in a such that |m-n|<=b.

So far, I've got this

def nearest_pairs(a, b):m= []n= intnum_pairs = 0return num_pairsdef main():# The nearest pairs are (1,2), (2,1), (2,5) and (5,2)x = nearest_pairs( [1,2,5] , 3 )print( "nearest_pairs([1, 2, 5], 3) = " , nearest_pairs([1, 2, 5], 3) )# The nearest pairs are (1,2) and (2,1)y = nearest_pairs( [1, 2, 5] , 2 )print( "nearest_pairs([1, 2, 5], 2) = " , nearest_pairs([1, 2, 5], 2) )if __name__ == '__main__':main()

The desired output should look like

>>> nearest_pairs([1,2,5],3) = 4

where 4 is the number of close pairs according to the restrictions. However, I get an error. Could anyone lead me to the right direction?

Yours doesn't make sense. No idea what you're trying with len(a, b), but it's not even allowed, since len takes only one argument. And returning something just when you found the first counting pair? Here's a fix:

def close_pairs(l, d):ctr = 0for a,b in permutations(l, 2):if (a - b) <= d and (b - a) <= d:ctr += 1return ctr

And here's how I'd do it:

def close_pairs(l, d):return sum(abs(a-b) <= d for a, b in permutations(l, 2))