Why tuples python

String Methods. Start Learning Python. Explore Python Examples. Related Topics Python tuple. Python Lists Vs Tuples In this article we will learn key differences between the List and Tuples and how to use these two data structure. Syntax Differences Syntax of list and tuple is slightly different. Example 1. In python we have type function which gives the type of object created. Example 2. Share on:. Did you find this article helpful? Sorry about that. Tuples support the same sequence operations as strings.

The index operator selects an element from a tuple. But if we try to use item assignment to modify one of the elements of the tuple, we get an error:. So like strings, tuples are immutable. Once Python has created a tuple in memory, it cannot be changed. To construct the new tuple, it is convenient that we can slice parts of the old tuple and join up the bits to make the new tuple.

So if julia has a new recent film, we could change her variable to reference a new tuple that used some information from the old one:. Python has a very powerful tuple assignment feature that allows a tuple of variables on the left of an assignment to be assigned values from a tuple on the right of the assignment. We already saw this used for pairs, but it generalizes. This does the equivalent of seven assignment statements, all on one easy line.

One requirement is that the number of variables on the left must match the number of elements in the tuple. Tuples are also more memory efficient than lists, though I'm not sure when that benefit becomes apparent.

Also check out the chapters on lists and tuples in Think Python. For input parameters it's best to accept the most generic interface that does what you need. It is seldom just a tuple or list - more often it's sequence, sliceable or even iterable. Python's duck typing usually gets it for free, unless you explicitly check input types.

Don't do that unless absolutely unavoidable. For the data that you produce output parameters just return what's most convenient for you, e. One thing to keep in mind is to avoid returning a list or any other mutable that's part of your state, e.

A minor but notable advantage of a list over a tuple is that lists tend to be slightly more portable. Standard tools are less likely to support tuples. JSON, for example, does not have a tuple type.

YAML does, but its syntax is ugly compared to its list syntax, which is quite nice. In those cases, you may wish to use a tuple internally then convert to list as part of an export process. Alternately, you might want to use lists everywhere for consistency. Stack Overflow for Teams — Collaborate and share knowledge with a private group. Create a free Team What is Teams? Collectives on Stack Overflow. Learn more. List vs tuple, when to use each? Asked 12 years ago.

Active 1 year, 11 months ago. Viewed k times. Improve this question. Unfortunately this question has been wrongly marked as a duplicate. A big reason you will often see lists being used over tuples in situations with no strong reasons for either is readability. Round braces are used for many things in Python, but square brackets are used only for list-related things. Add a comment. Active Oldest Votes. You can't add elements to a tuple. Tuples have no append or extend method.

You can't remove elements from a tuple. Tuples have no remove or pop method. You can also use the in operator to check if an element exists in the tuple. Slicing can be best visualized by considering the index to be between the elements as shown below. So if we want to access a range, we need the index that will slice the portion from the tuple. This means that elements of a tuple cannot be changed once they have been assigned.

But, if the element is itself a mutable data type like a list, its nested items can be changed. This is called concatenation. As discussed above, we cannot change the elements in a tuple. It means that we cannot delete or remove items from a tuple. Deleting a tuple entirely, however, is possible using the keyword del. Methods that add items or remove items are not available with tuple. Only the following two methods are available.

Since tuples are quite similar to lists, both of them are used in similar situations. However, there are certain advantages of implementing a tuple over a list. Below listed are some of the main advantages:. Course Index Explore Programiz. Python if Statement. Python Lists.