MemoryError in data conversion

[Mok-Kong Shen]

The code attached below produces in one of the two IMHO similar cases
(excepting the sizes of the lists involved) MemoryError. Could experts
kindly tell why that's so and whether there is any work-around feasible.

Thanks in advances.

M. K. Shen

-----------------------------------------------------------------

import ast

def buildhuffmantree(slist,flist):
   item=slist[:]
   freq=flist[:]
   while len(item)>2:
     mn=min(freq)
     id=freq.index(mn)
     u=item[id]
     del item[id]
     del freq[id]
     mn1=min(freq)
     id=freq.index(mn1)
     v=item[id]
     del item[id]
     del freq[id]
     item.append([u,v])
     freq.append(mn+mn1)
   return(item)

def processing(slist,flist):
   bintree=buildhuffmantree(slist,flist)
   print(bintree)
   byarray=bytearray(str(bintree),"latin-1")
   bintree1=ast.literal_eval(byarray.decode("latin-1"))
   print(bintree1)
   print(bintree==bintree1)

slist1=[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 'eof']

flist1=[18, 16, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 1, 1, -1]

slist2=[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17,
         18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33,
         34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49,
         50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65,
         66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81,
         82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97,
         98, 99, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110,
         111, 112, 113, 114, 115, 116, 117, 118, 119, 120, 121, 122, 123,
         124, 125, 126, 127, 'eof']

flist2=[2, 2, 0, 2, 0, 0, 1, 2, 1, 0, 2, 0, 0, 1, 1, 0, 2, 0, 0, 0, 1,
         0, 0, 0, 2, 0, 0, 1, 0, 0, 0, 0, 2, 0, 0, 0, 0, 0, 1, 0, 0, 0,
         0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
         0, 1, 0, 2, 0, 0, 1, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0,
         0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0,
         0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
         0, 0, -1]

processing(slist1,flist1)  ### This works fine
print()

processing(slist2,flist2)  ### This leads to MemoryError