TypeError dict keys object does not support indexing

Question

def shuffle self  x  random None  int int          x  random random random - gt  shuffle list x in place  return None       Optional arg random is a 0-argument function returning a random     float in  0 0  1 0   by default  the standard random random               randbelow   self  randbelow     for i in reversed range 1  len x               pick an element in x  i 1  with which to exchange x i          j   randbelow i 1  if random is None else int random      i 1           x i   x j    x j   x i    When I run the shuffle function it raises the following error  why is that   TypeError   dict keys  object does not support indexing

User · Accepted Answer

Clearly you re passing in d keys   to your shuffle function   Probably this was written with python2 x  when d keys   returned a list    With python3 x  d keys   returns a dict keys object which behaves a lot more like a set than a list   As such  it can t be indexed   The solution is to pass list d keys     or simply list d   to shuffle

User · Answer

Convert an iterable to a list may have a cost  Instead  to get the the first item  you can use   next iter keys     Or  if you want to iterate over all items  you can use   items   iter keys  while True      try          item   next items      except StopIteration as e          pass   finish

User · Answer

In Python 2 dict keys   return a list  whereas in Python 3 it returns a generator   You could only iterate over it s values else you may have to explicitly convert it to a list i e  pass it to a list function

User · Answer

Why you need to implement shuffle when it already exists  Stay on the shoulders of giants   import random  d1    0  zero   1  one   2  two   3  three   4  four        5  five   6  six   7  seven   8  eight   9  nine    keys   list d1  random shuffle keys   d2      for key in keys  d2 key    d1 key   print d1  print d2

User · Answer

You re passing the result of somedict keys   to the function  In Python 3  dict keys doesn t return a list  but a set-like object that represents a view of the dictionary s keys and  being set-like  doesn t support indexing   To fix the problem  use list somedict keys    to collect the keys  and work with that

[python] TypeError: 'dict_keys' object does not support indexing

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