minimal distance between elements on list

import numpy as np

# --- version 1 ---

def np_min_distance(data, val1, val2):
    pos1 = np.where(data == val1)
    pos2 = np.where(data == val2)

    dist = 0

    for x in pos1[0]:
        for y in pos2[0]:
            d = abs(x-y)
            if dist == 0 or d < dist:
                dist = d

    return dist


data = np.array([1, 5, 3, 7, 2, 8, 3, 4, 5, 9, 9, 3, 1, 3, 2, 9])

print( '4, 7 -> 4', np_min_distance(data, 4, 7) == 4 )
print('---')

print( '9, 3 -> 1', np_min_distance(data, 9, 3) == 1 )
print('---')

data = np.array([4, 4, 4, 4, 7, 7, 7, 7, 4, 4])

print( '4, 7 -> 1', np_min_distance(data, 4, 7) == 1 )
print('---')


print('------------------------------------------------')

# --- version 2 ---

def min_distance(data, val1, val2):
    pos1 = None
    pos2 = None
    dist = 0 # or some big value
    previous = None

    for pos, item in enumerate(data):

        if item == val1:
            pos1 = pos
            if pos1 and pos2 and previous != val1: # if `pos1` and `post2` is not `None` then `previous` can't be `None` so I don't have to check if `previous is not None`
                d = abs(pos1 - pos2)
                print('pos:', pos1, pos2, '->', d)
                if dist == 0 or d < dist:
                    dist = d
                #if dist == 1:
                #    return 1
            previous = val1

        elif item == val2:
            pos2 = pos
            if pos1 and pos2 and previous != val2:
                d = abs(pos1 - pos2)
                print('pos:', pos1, pos2, '->', d)
                if dist == 0 or d < dist:
                    dist = d
                #if dist == 1:
                #    return 1
            previous = val2

    #print('result:', dist)

    return dist # zero means no found


data = [1, 5, 3, 7, 2, 8, 3, 4, 5, 9, 9, 3, 1, 3, 2, 9]

print( '4, 7 -> 4', min_distance(data, 4, 7) == 4 )
print('---')

print( '9, 3 -> 1', min_distance(data, 9, 3) == 1 )
print('---')

data = [4, 4, 4, 4, 7, 7, 7, 7, 4, 4]

print( '4, 7 -> 1', min_distance(data, 4, 7) == 1 )
print('---')

print( '9, 3 -> 0', min_distance(data, 9, 3) == 0 )
print('---')