Python-сообщество

str = "fffas"
x=0
while x !=len(str):
        if str[x] == str[x+1]:
                      True
                      break
        else:
                      False
if False:
           del str

list = ["fffds","fffdj","fffdk","fffdl","fffjj","fffjk,"fffjl"]
for str in list:
       while x !=len(str):
          if str[x] == str[x+1]:
                      True
                      break
          else:
                      False
       if False:
              str = ""
nstr = 0
l = len(list)
while nstr!= l:
          if list[nstr]=="":
                       for x in list [nstr:]:
                                 list[x] = list[x+1]
                       l = l-1
          nstr = nstr +1

>>> list_src = ['fffds', 'fffdj', 'fffdk', 'fffdl', 'fffjj','fffjk', 'fffjl',  'fgsdf']
>>> list_prs = []
>>> list_sng = []
>>> for s in list_src:
...     [list_sng, list_prs][1 in map(len, map(set, zip(list(s) + [None], [None] + list(s))))].append(s)
...
>>> list_prs
['fffds', 'fffdj', 'fffdk', 'fffdl', 'fffjj', 'fffjk', 'fffjl']
>>> list_sng
['fgsdf']

from itertools import imap, izip
(x for x in lst if 1 not in imap(len, imap(set, izip(x[1:], x[:-1]))))

def list_filter_classic(list_src):
    list_dst=[]
    for string in list_src:
        for i in xrange(len(string)-1):
            flag=False
            if string[i]==string[i+1]:
                flag=True
                break
        if flag is False:
            list_dst.append(string)
    return list_dst