Ascending and descending

def sort_asc(arr):
  for y in range(len(arr)-1,0,-1):
    for x in range(y):
      if arr[x]>arr[x+1]:
          temp = arr[x]
          arr[x] = arr[x+1]
          arr[x+1] = temp
  return arr

def sort_desc(arr):
	for desc in range(len(arr)-1,0,-1):
		for x in range(desc):
			if arr[x]<arr[x+1]:
				des = arr[x+1]
				arr[x+1] = arr[x]
				arr[x] = des
	return arr

def weird_sort(nums):
	new_array = []

	# sort the array with the sort function
	arr = sort_asc(nums)
	# divide the array into two parts
	first_halve = arr[0:int((len(arr)+1)/2)]
	second_halve = arr[int((len(arr)+1)/2):]

	# Put the first half into the rearranged array
	second_halve = sort_desc(second_halve)
	new_array = first_halve + second_halve

	return new_array


a = [89,45,56,23,84,55,67,59,12,74]

print weird_sort(a)

Camel to Snake case

def take_string(arr):
    snake=""
    for i in arr:
         if (ord(i) >= 65) and (ord(i) <= 90):
             if snake == "":
                 snake = snake + i.lower()
             else:
                 snake = snake + "_" + i.lower()
         else:
             snake = snake + i

    print snake


take_string("MyWords")

Second and Second to the last values

def sort(arr):
  for y in range(len(arr)-1,0,-1):
    for x in range(y):
      if arr[x]>arr[x+1]:
          temp = arr[x]
          arr[x] = arr[x+1]
          arr[x+1] = temp
  return arr

arr = [54,26,93,17,77,31,44,55,20]
sorted =  sort(arr)
print sorted

def pick_two(sorted_arr):
    new = []
    new = [sorted_arr[1],sorted_arr[-2]]
    return new


print pick_two(sorted)