sorting - RunTimeError in merge sort function using python -

i trying write merge sort function using python 2 runtimeerror

input: unsorted list (ex:[10,9,8,7,6,5,4,3,2,1])

output: [1,2,3,4,5,6,7,8,9,10]

my code shown below:

lst = [10,9,8,7,6,5,4,3,2,1] def mergesort(array): if len(array) == 1:     return array left = [] right = [] in array:     if <= len(array)/2:         left.append(i)     else:         right.append(i) left = mergesort(left) right = mergesort(right) return merge(left,right)  def merge(left,right):     sortedlist= []     while left , right:         if left[0]>right[0]:             sortedlist.append(right[0])             right.pop(0)         else:             sortedlist.append(left[0])             left.pop(0)     while left:         sortedlist.append(left[0])         left.pop(0)     while right:         sortedlist.append(right[0])         right.pop(0)      return sortedlist   print mergesort(lst) 

the runtimeerror is: maximum recursion depth exceeded. know cause of error?

you're comparing list values list indices:

for in array: # list value     if <= len(array)/2: # len(array)/2 list index 

change if <= array[len(array)/2]: , should work.