How to create a tuple of an empty tuple in Python?

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How can I create a tuple consisting of just an empty tuple, i.e. (())? I have tried tuple(tuple()), tuple(tuple(tuple())), tuple([]) and tuple(tuple([])) which all gave me ().

The reason that I use such a thing is as follows: Assume you have n bags with m items. To represent a list of items in a bag, I use a tuple of length n where each element of that tuple is a representative for a bag. A bag might be empty, which is labeled by (). Now, at some initial point, I have just one bag with empty items!

The empty tuple is () (or the more-verbose and slower tuple()), and a tuple with just one item (such as the integer 1), called a singleton (see here and here) is (1,). Therefore, the tuple containing only the empty tuple is

((),)

Here are some results showing that works:

>>> a=((),)
>>> type(a)
<type 'tuple'>
>>> len(a)
1
>>> a[0]
()
>>> type(a[0])
<type 'tuple'>
>>> len(a[0])
0

How to create an empty tuple in Python?, The empty tuple is () (or the more-verbose and slower tuple() ), and a tuple with just one item (such as the integer 1 ), called a singleton (see  How to create an empty tuple in Python? Python Server Side Programming Programming. You can create empty tuple object by giving no elements in parentheses in assignment statement. Empty tuple object is also created by tuple () built-in function without any arguments. >>> T1 = () >>> T1 () >>> T1 = tuple() >>> T1 ()

I'm not surprised this (()) didn't work, since the outer parentheses get interpreted as that - parentheses. So (()) == (), just like (2) == 2. This should work, however:

((),)

How to create a tuple of an empty tuple in Python?, empty tuples. Empty tuple acts as a singleton, that is, there is always only one tuple with a length of zero. When creating an empty tuple Python  Tuples are an ordered sequences of items .An empty tuple in python can be created in two ways: There are two ways to initialize an empty tuple. You can initialize an empty tuple by having with no values in them. emptyTuple = You can also initialize an empty tuple in python by using the tuple function. emptyTuple = tuple()

tuple() is the only genuine empty tuple, but (), and ((),) create a tuple of length 1 that contains a tuple of length 0 - but not a tuple of length zero itself.

If you want an answer to "how do I create an empty (or zero length) tuple.... I found this post with the search "how to create an empty tuple", then realised this was not the same question, but could be mistaken for that question (as the search does), so I though I would provide the answer to :

How do you simply create an empty tuple?

the original question could mislead you, as the original answers are almost good enough as an empty tuple, but do fail one test.

(), will create an 'empty' tuple as suggested in previous answers with ((),) which will also work, as will ((( ((( (),))) ))) in fact you can use any number of outer brackets you choose, they just work as brackets. However, python, when printing a tuple, does add one set of outer brackets.

empty brackets is a non-standard representation of 'no value' and adding the trailing comma makes a tuple from 'no value'. But it is a tuple with a 'no value' entry, not an empty tuple.

Note: This is not a zero length tuple, as the other examples have also shown. The outer tuple is a tuple with one value, just that value has itself, is the empty tuple. So this creates an empty tuple inside another tuple, and the other tuple is not empty. For a true empty tuple by itself, use tuple() although the (), behaves some what similar, it is not quite correct.

>>>  a = (),
>>> type(a)
<class 'tuple'>
>>> len(a)
1
>>> a
((),)
>>> len(a[0])  # the inside tuple is empty, just not the outside one
0

Similarly, for a tuple of length 1 but with a value (of zero in the case of b, and "" for the example with c)

>>> b = 0,
>>> type(b)
<class 'tuple'>
>>> len(b)
1
>>>b
(0,)
# now with an empty string
>>> c = "",
>>> type(c)
<class 'tuple'>
>>> len(c)
1
>>>c
('',)
>>> len (c[0])  # same len of c[0] as with 'empty' tuple
0

So the outer brackets are included for displaying a tuple, but not actually part of the tuple, nor needed for creating the tuple.

However all these brackets methods are not a real empty at the outer level, which is something that also has use cases.

>>> a = ((),)  # extra brackets just to show same as other answers
>>> len(a)
1
>>> if a:
   print("not empty")
not empty
>>> e = tuple()
>>> len(e)
0
>>> type(e)
<class 'tuple'>
>>> if e:
   print("not empty")

>>> # note...did not print...so e acts as false as an empty tuple should

So if you really need a genuine empty tuple, use tuple(), but if near enough is all you need, you can use (), or ((),)

Python Tuples and Tuple Methods - Michael Galarnyk, Python Tuples: Insert, modify, remove, slice, sort, search element(s) and more of a #create an empty tuple >>> tuplex = () >>> print (tuplex)  Varun August 5, 2018 Python Tuple: Different ways to create a tuple and Iterate over it 2018-08-05T09:41:09+05:30 Python, Tuple No Comment In this article we will discuss what is tuple, how its different from list, different ways to create a tuple and iterate over it.

Tuples in Python, Create an empty tuple : Tuple Declaration « Tuple « Python. In this post, we will see what is the tuple, how its different from the list, how we can create them and iterate to use them. What is tuple In python, a tuple is seal packet of data container which could store different elements, as said they are seal package we can’t change them or their elements after creation.

Optimization tricks in Python: lists and tuples, In Python, a tuple is similar to List except that the objects in tuple are immutable which means we cannot change the To create a tuple in Python, place all the elements in a () parenthesis, separated by commas. empty tuple my_data = ()  Tuple is a sequence in Python, a collection of Python objects. Tuples are immutable, you cannot update tuple or any of its elements.

Python Tuples, A tuple is created by placing all the items (elements) inside types of tuples # Empty tuple my_tuple = () print(my_tuple) # Tuple  Do not use this if the tuple may already be known to some other part of the code. The tuple will always grow or shrink at the end. Think of this as destroying the old tuple and creating a new one, only more efficiently. Returns 0 on success. Client code should never assume that the resulting value of *p will be the same as before calling this

Comments
  • Empty tuple literal is (), not (,)
  • @DeepSpace That's right. This tuple is then used to create a new tuple and I store all the tuples somewhere for logging.
  • A tuple with 5 tuples inside it is ((),)*5.
  • @jeffery_the_wind This does not create the one I want, but thanks for offering lists. It helped me in the following working code tuple([tuple()]). Also, the following answers are just tuple based which much desirable.
  • Aside from the comma confusion, the key insight here is that the tuple() constructor is a converter, not a container. That is, you have to give it some kind of container (technically an iterator). That's why tuple(1) is a TypeError. So while tuple() is indeed an empty tuple, tuple(tuple()) is just that converted to another empty tuple.
  • This is the correct answer to the actual question, but caution, this does not show how to create a simple empty tuple. If you came looking just an empty tuple, not 'a tuple that contains an empty tuple' then use caution!
  • @innov8: My answer opens with "The empty tuple is ()". It does indeed "show how to create a simple empty tuple." It then goes on to also show how to "create a tuple consisting of just an empty tuple."
  • @rory_daulton your answer is a perfect answer to the question. My point is that you can land on this page for another question 'how to create an empty tuple' - which is different question. Of course you did not focus on a question which was not asked!
  • part of this seems to be valid only for python 2, in python 3 a = (); len(a) returns 0
  • yes, you must use a=(),;len(a) as without the trailing comma, you will not get the desired result. You get a tuple, not a tuple within a tuple