Many types in Python are immutable. The list is mutable. The list is a data type that is mutable. Answer = immutable type :- those types whose value never change  is known as immutable type. Let’s say you replaced it with just a single one. Okay, perfect. Python supports many simple and compound datatypes.. Few data types like list, dictionary are mutable and others like string datatype, tuple are immutable. Let’s say you replaced it with just a single one. Objects in Python can be Mutable or immutable. 06:58. Generic selectors ... Let’s see an example where the tuple elements are mutable and we change their properties. A single value in a list can be replaced by indexing and then doing simple. item. Again, a[1:4] should be those three. That would remove those, deleting. 02:55 In Python, everything is an object. Since lists are mutable data structures, Python is able to just add an element to an existing list instead of creating an entirely new object. A list has a variable size while a tuple has a fixed size. So, this is 3 and we could go up to the end and say that’s equal to an empty list. This is a very simple definition of a Mutable and Immutable object in Python. 02:50 06:38 The items of a list are arbitrary Python objects. So many of Python object types are immutable. First, we will learn the definition of mutable objects. that’s also called the augmented assignment operator would allow you to append a. putting them at the tail of the list here. In this lesson, you’ll explore how Python lists are both mutable and dynamic. They are mutable. Okay, if you’ve worked with strings, you might be aware that a string is an iterable. A single value in a list can be replaced by indexing and then doing simple assignment. so the code below does not work. and then you were to index a particular item—such as in this case, a[2], which is 'bacon'—but instead of just calling it out to have it returned, reassign it. Mutable means that you can change the items inside, while ordered sequence is in reference to index location. Immutable objects are faster to access and are costlier to change because it needs the creation of a copy. This website provide you previous year question paper, python program, Facts, about technology and etc. Well, it might not be the way you thought. even the order of the elements can be changed. Python compiler handles function arguments slightly different than other popular programming languages like C, C++, and Java but much like Ruby.Python function arguments behavior is confusing when a “mutable” object, like Python dict (dictionary), set or list, is involved in the function argument list.The behavior of Python function arguments or parameters is interesting and confusing for the … Why is Tuple Immutable Data Type in Python? Lists As you saw earlier, lists are mutable. ^_^Please do not send spam comment : ), You can uderstand by watching videos ----. The difference may seem simple, but the effect of both these objects is different in programming. Mutable vs Immutable Replacing an item in List vs Tuple “Yes… I use Visual Studio Code for Python debugging. And let’s say you delete a[3]. Python containers contain references to other objects. So what about appending items to a list? In this case, += [30]—it doesn’t have a problem with that because type([30]) is a list, compared to type(30) without square brackets is an integer. That’s what it would look like. Every object has its own data type and internal state (data). Thank you, Chris. So you can’t just add a simple integer to it. Now, one note: if you aren’t using a slice syntax here, and let’s say you just say a[1], which is 'a' here, if you were to replace a[1] and not a slice with a list, it’s going to insert that as a sublist, because it’s not indicating a slice here. Put an integer, 10. Please try to debug it.. you will get following result. Okay, what happens if you add it? Let’s say between 1 and 2—basically meaning this item right here, 'Hello'—you wanted it to be…. 03:18 Consider a tuple. Let’s discuss them one by one. And then in here you just put an iterable, such as a list. They are unordered collections of immutable objects. 04:23 Objects of built-in types like (list, set, dict) are mutable. If you wanted to change several contiguous elements in a list all at one time, you could do it with slice assignment. What is Python List? And then in here you just put an iterable, such as a list. So again, here, a[1:4], and then you’d reassign it to an empty list. Things like an integer or a float, or even a sequence type object like a string—they’re all immutable, meaning that you can’t change the characters within that string or change the value of that integer or that float. What do you think is going to happen? Well. So what about appending items to a list? So the list can grow or shrink depending on how you use it. you get to practice the methods that are available to lists. Python provides two set types, set and frozenset. And it will replace a slice, let’s say 1 through 4, which should be these three items here. Once a list has been created, elements can be added, deleted, shifted, and moved around at will. if you try to reassign this, the third index, the letter 'b' in the string, that’ll raise an exception, a TypeError. So now you’ve inserted four of these items in the place where it was this one, so the length now of a is actually 6. what are the differences? Once one of these objects is created, it can’t be modified, unless you reassign the object to a new value. In your first code example you are trying to mutate the string that is assigned to s, by accessing the third element (item) and changing it. We know that tuple in python is immutable. Byte arrays represent the mutable version of bytes objects. (s = 42) or s = [1, 2, 3]. The List is a mutable sequence of objects, and the list class represents the … (Note that there are no special cases needed to form lists of length 0 or 1.) Each element or value that is inside of a list is called an item. 02:42 On the other hand, some of the immutable data types are int, float, decimal, bool, string, tuple, and range. 00:55 The list is an ordered collection of data types. So if you wanted to insert all three of these items differently—so let’s say, again, you might remember del—and you wanted right in here to insert these three items, well, that would be a[1:1]. You can help us by Clicking on ads. In this case, it doesn’t have a problem with that because. Python List – list class. So let’s say we want to change these three. And if you want to delete multiple items, another way that you could accomplish that—let’s say you want to get rid of all the integers in here. and that would insert all three of these before the rest. Summary: Passing mutable objects as default arguments leads to unexpected outputs because Python initializes the default mutable object only once, not (as you may have expected) each time the function is called.To fix this, initialize the mutable default argument with the None keyword in the argument list and then initialize it within the function. 01:21 and then you were to index a particular item—such as in this case. And you can see it’s reassigned all three of those. In Python, only dictionaries and lists are mutable objects. Well, we were using the concatenation operator earlier. So you can’t just add a simple integer to it. Mutable sequences can be changed after they are created. Python just grows or shrinks the list as needed. Comparing list( Mutable ) with string ( immutable ) When we assign a different value to a string variable we are not modifying the string object, we are creating a new string object. s[2] = ‘f’, what about code below? It tells you straight up that the 'str' object does not support item assignment, the way a list does. Byte Arrays. Again, it’s going to take all three of these items and replace it with a single list. So here’s a, and let’s say you wanted to add 'tomato' to your list. If you assign to, let’s say with a couple of integers at the beginning, and then concatenated it to, “Can I just add on a single item?” If you were to. Every object has an identity, a type, and a value. Mutable and Immutable in Python. But the tuple consists of a sequence of names with unchangeable bindings to objects. To put it simply, mutable objects are those that allow their state (i.e data which the variable holds) to change. Here's another example using the append() method: a = list (('apple', 'banana', 'clementine')) print (id (a)) a. append ('dates') print (id (a)) … Now let’s discuss other immutable and mutable data types! List immutable and mutable types of python. Basically a zero-length slice as the index. This is why people say that Python passes neither by value or reference, but instead by “call by object reference”. Numeric objects such as integer, float and complex number objects occupy the memory and memory contents can not be changed. You have to understand that Python represents all its data as objects. In this lesson, you’ll explore how Python lists are both mutable and dynamic. list_1 = [1,2,3] tuple_1 = (1,2,3) list_1[0] = 5 tuple_1[0] = 5. Mutable datatypes means changes can be done and are reflected in same variable. Now, this is what we’re talking about the list being dynamic. 05:18 Python tuple is an immutable sequence. Well, you would say, and then you’d reassign it to an empty list. Operations on tuples can be executed faster compared to operations on lists. As we can see that the memory location or the ID of the list remained the same while the values changed. 7 = What are immutable and mutable types? So, objects of type int are immutable and objects of type list are mutable. Which will throw: TypeError: ‘str’ object does not support item assignment. Immutable are quicker to access than mutable objects. It also allows duplicate records in the data set. So now you’ve inserted four of these items in the place where it was this one. Let me simplify, make it a little bit shorter. Such objects are called immutable. Integers, floats, strings, and (as you’ll learn later in this course) tuples are all immutable. I am not sure where to locate the description of a video. There are newer data types in python that allows to change the original variable data. I have created a tutorial to setup Visual Studio Code for Python debug. This is because Python (a) only evaluates functions definitions once, (b) evaluates default arguments as part of the function definition, and (c) allocates one mutable list for every call of that function. Say you had list. Let’s put some floats in. String and dictionary objects are also immutable. Okay, if you’ve worked with strings. Some of these objects like lists and dictionaries are mutable , meaning you can change their content without changing their identity. Lists. The list a is mutable. An object’s mutability is determined by its type. If you wanted to change several contiguous elements in a list all at one time, instead of just index assignment, you could do it with slice assignment. This lesson is for members only. Some types in Python can be modified after creation, and they are called mutable. Hi DJ, Some of the mutable data types in Python are list, dictionary, set and user-defined classes. And lists are also dynamic, meaning that you can add elements to the list or remove elements from a list. And then you could just enter a list. What is an immutable object? myList = ["Apple","Orange","Grapes"] print(id(myList)) The above is a list data type which is mutable. If you’ve worked with strings before, you might remember that. Join us and get access to hundreds of tutorials and a community of expert Pythonistas. The first element in a list will always be located at index 0. Mutability is a property that allows change/update. Mutable Data Types Lists. We can also see that the updated list persists outside of our function scope. Take the last one, change that to an integer of 20. And if you want to insert multiple items, you can accomplish that too. Once a list has been created: Lists are also dynamic. Once a list has been created: Elements can be modified. All the data in a Python code is represented by objects or by relations between objects. So, lists are pretty unique. If list and dictionary are mutable variables, it’s really confusing as a tuple is immutable. we were using the concatenation operator earlier. 02:25 Now, one note: if you aren’t using a slice syntax here, and let’s say you just say, it’s going to insert that as a sublist, because it’s not indicating a slice, here. See this example: >>> a = [] >>> b = [a] >>> b [[]] >>> a.append(1) >>> b [[1]] In this b is a list that contains one item that is a reference to list a. You aren’t changing the “string” but instead giving s a wholly different string. Rebuild a as a list of those strings again. That’s changed it, changed the value within the list. BTW, loving the list and tuple video series :). Elements can be added and deleted from a list, allowing it to grow or shrink: 00:00 Might sound trivial but I am not able to get the link about sort in description of the video. In Python, strings are also immutable. Let’s put some floats in. Not only can you change out that item from your list, but you can use the del (delete) function. Next, you get to practice the methods that are available to lists. In this case, since this is an iterable, it broke it apart into individual characters. They expose most of the usual methods of... Sets. list. Let me have you try it out. So in that case, it’s going to take all three of these items and replace it with a single list item. That means you can change it without re-declaring it in a new location. So let’s say we want to change these three. How to create a tuple, iterate over a tuple, convert list to a tuple, convert string to a tuple, Python Tuple vs List. 01:07 05:53 The list is the first mutable data type you have encountered. ['spam', 'egg', 'bacon', 'tomato', 'ham', 'lobster'], ['spam', 'egg', 10, 'tomato', 'ham', 'lobster'], 'str' object does not support item assignment, ['spam', [22, 33, 44], 'b', 'c', 'd', 3.3], ['spam', 'egg', 'bacon', 'tomato', 'ham', 'lobster', 'gravy', 'kiwi'], [10, 20 'spam', 'egg', 'bacon', 'tomato', 'ham', 'lobster', 'gravy', 'kiwi'], [10, 20 'spam', 'egg', 'bacon', 'tomato', 'ham', 'lobster', 'gravy', 'kiwi', 30], ['spam', 'egg', 'bacon', 't', 'o', 'm', 'a',' t', 'o']. If you assign to a a list, let’s say with a couple of integers at the beginning, and then concatenated it to a itself, that would put the two at the beginning, prepending as opposed to appending to the list a. Well, you could do it a little differently. Example = integer, string, Boolean, tuples, e.c.t Take a list (mutable object) and a tuple (immutable object). So here’s a. Now we have two new terminologies: Mutable and Immutable in Python. But the contents of the list can change. A list is a data structure in Python that is a mutable, ordered sequence of elements. List are dynamic and can contain objects of different data types. Things like an integer or a float, or even a sequence type object like a string—, meaning that you can’t change the characters within that string or change the, Once you create that object and you assign it, it’s immutable, And we’re going to discuss another cousin of a list called the tuple and how. That would remove those, deleting them. s = ‘abcdef’. Python Mutable Type. This causes the mutable default argument to be initialized freshly … Become a Member to join the conversation. Now coming to the interesting part which is Mutable Default Object in function definitions. Integers, floats, strings, and (as you’ll learn later in this course) tuples are all immutable. and that would insert all three of these before the rest. ... Mutable List vs Immutable Tuples. Once you create it, elements can be modified. Join us and get access to hundreds of tutorials and a community of expert Pythonistas. Python handles mutable and immutable objects differently. 06:29 List has mutable nature i.e., list can be changed or modified after its creation according to needs whereas tuple has immutable nature i.e., tuple can’t be changed or modified after its creation. And if you want to insert multiple items, you can accomplish that too. For example, we know that we can modify the contents of a list object: >>> my_list = [1, 2, 3] >>> my_list[0] = 'a new value' >>> my_list ['a new value', 2, 3] And so you might say, “Can I just add on a single item?” If you were to += and then just add a 30 as an integer to the end of it, it’s going to be mad because it’s not an iterable. What is Mutable and Immutable? Mutable: It is a fancy way of saying that the internal state of the object is changed/mutated. Once one of these objects is created, it can’t be modified, unless you reassign the object to a new value. Well, that deleted 'tomato' right out of that list. What if you wanted some at the beginning? A mutable object can change its state or contents and immutable objects cannot. Identities remain same for mutable objects but changes for immutable objects. list_fruits = ["Apple"] tup = ("Hello", … you might be aware that a string is an iterable. Okay, perfect. them. And you can see it’s reassigned all three of those. Thanks. The list is a collection of items/data which is ordered and can be changed whenever needed. Make sense. Now, this is what we’re talking about the list being dynamic. As python is a dynamically typed language you could even reassign s to an integer, or a some other type than a string. Some of Python's mutable data types are: lists, byte arrays, sets, and dictionaries. Okay, what happens if you add it? Lists are formed by placing a comma-separated list of expressions in square brackets. A version of the concatenation operator that’s also called the augmented assignment operator would allow you to append a couple additional items onto your list. Not only can you change out that item from your list. putting them at the tail of the list here. Do another one. The list is one of the most used in Python for traversing the elements. Mutable Objects in Python. Whereas mutable objects are easy to change. Christopher Bailey So many of Python object types are immutable. Let me simplify a a little bit, make it a little bit shorter. They are mutable. I like the way you teach this Python course and I am looking for similar course formats as offrened in RealPython, in other language as C# Java SQL, with the following criteria: Hi Chris, without square brackets is an integer. BTW: The tutorial is very help. If you wanted to add it more properly, 'tomato' would have to be inside of a list as a singleton. Python provides a wide range of ways to modify lists. So if you wanted to insert all three of these items differently—. Once you create it, elements can be modified, individual values can be replaced, even the order of the elements can be changed. Data Structures : Stacks and Queues using Lists, Relational Database and SQL (Preeti Arora), Table Creation and Data Manipulation Commands. 01:52 03:32 Here you’ll put in m being your first index, and n being again going up to but not including. What if you wanted some at the beginning? And we’re going to discuss another cousin of a list called the tuple and how it’s immutable also. In this Python tutorial, we will learn what are mutable and immutable objects in Python and the differences between them. So that’s where you could use that singleton list. Basically a zero-length slice as the index. tup = ([3, 4, 5], 'myname') The tuple consists of a string and a list. That’s what it would look like. We can conclude that although both lists and tuples are data structures in Python, there are remarkable differences between the two, with the main difference being that lists are mutable while tuples are immutable. Well, you could do it a little differently. A bytearray object is a mutable array. Any object in Python whose internal state is changeable can be called a mutable. it broke it apart into individual characters. They are created by the built-in bytearray() constructor. it’s going to be mad because it’s not an iterable. Python just grows or shrinks the list as needed. So here’s. And lists are also dynamic, meaning that you can add elements to the list or remove elements from a list completely. So the list can grow or shrink depending on how you use it. And then you could just enter a list. Well, you would say from a[1:5]. But it is. 00:20 Once you create that object and you assign it, it’s immutable unless you reassign it. As you saw earlier, lists are mutable. It has to be an iterable. How to create a tuple, iterate over a tuple, convert list to a tuple, convert string to a tuple, Python Tuple vs List. Do not put a mutable object as the default value of a function parameter. As concatenation occurs at the list (mutable), no new object is created. Tuple is also immutable. Strings are immutable so we can’t change its value. Mutable objects can be changed , whereas immutable object can't be changed. it’s immutable also. This is perfectly fine as lists are mutable their states can be modified. That should clear those out, right? In this example, t is an immutable object (tuple) but its elements list_1 & list_2 are mutable objects. That’s good. s = ‘abc’ The mutable objects are the objects that are able to modify(i.e., delete, update, change etc.,)even after the creation of the object. Similarly, the objects with a static state or ones that can’t be changed are immutable. Well, it might not be the way you thought. Mutable type: - those type whose value can be change is known as mutable type. List; Dictionary; Set Mutable and immutable objects are treated differently in python. Other objects like integers, floats, strings and tuples are objects that can not be changed. So that’s where you could use that singleton list. By this we can say that a list is a “mutable” object or a changeable object. ... Byte Arrays. List elements can be accessed by index number. Which means that Python allocated more memory space to the location to consider the additional values. Python List vs. Tuples. You could practice it a little bit here. Immutability on the other hand doesn’t allow change. Lists and Tuples in Python Mutable Sequence Types . completely. In your second code example you are reassigning the object s to a new value, which is possible. 00:33 So, lists are pretty unique. In this article we will learn key differences between the List and Tuples and how to use these two data structure. And if you want to delete multiple items, another way that you could accomplish, that—let’s say you want to get rid of all the integers in here. Now the second question. 01:37 05:00 Example = integer , string , Boolean, tuples , e.c.t. 02:05 strings are immutable. It has to be an iterable. That’s changed it, changed the value within the list. That’s good. That should clear those out, right? Take the last one, change that to an integer of, If you’ve worked with strings before, you might remember that, if you try to reassign this, the third index, the letter. Immutable types are perfectly safe. s = ‘mybacon’ Many types in Python are immutable. Do another one. The list is a data type that is mutable. This is Path walla website which help you to make your way of life. list_1 = [10, 20] list_2 = [40, 50] t = (list_1, list_2) print(t) >>> ([10, 20], [40, 50]) list_1.append(30) list_2.append(60) print(t) >>> ([10, … Answer = immutable type :- those types whose value never change is known as immutable type. For this video, I’m going to show you how lists are mutable and dynamic. It is used along with tuples, dictionaries, and sets. What do you think is going to happen? You could practice it a little bit here. 03:41 For this video, I’m going to show you how lists are mutable and dynamic. Here you’ll put in. Be the way you thought do it with just a single value in new. Tuple is immutable a string is an ordered collection of items/data which ordered. Mutable version of bytes objects types are: lists are also dynamic, meaning that you can change value... Of these before the rest and the differences between them as concatenation occurs at the tail of the can... The creation of a list has a variable size while a tuple has a variable size a. Discuss another cousin of a list all at one time, you to. And dynamic example, t is an ordered collection of data types about. Dictionaries, and ( as you ’ ll explore how Python lists are both mutable and immutable is list mutable in python! Vs tuple “ Yes… I use Visual Studio Code for Python debug [ 3, 4 which. Faster to access and are costlier to change these three items here names! S changed it, it doesn ’ t change its value not sure where locate. It ’ s going to be inside of a string and a completely... Multiple items, you could use that singleton list now let ’ s going to?. Individual characters one of these items and replace it with just a single value in list! Tuple ) but its elements list_1 & list_2 are mutable and dynamic so you... T change its value understand that Python passes neither by value or reference, but the of! To operations on tuples can be called a mutable object can change the inside! Data set tup = ( 1,2,3 ) list_1 [ 0 ] = ‘ mybacon ’ discuss! Not be the way you thought the interesting part which is ordered and can changed... Program, Facts, about technology and etc create it, elements can be replaced indexing. To take all three of these items differently— of ways to modify lists we have two new terminologies: and... Would insert all three of those strings again our function scope set types, set and user-defined classes video. Say 1 through 4, 5 ], and then you ’ d it., a type, and let ’ s see an example where the consists. New terminologies: mutable and immutable objects are faster to access and are costlier to change three! Me simplify, make it a little bit shorter multiple items, you could that. Typed language you could do it with a single value in a list can grow or shrink on! Along with tuples, e.c.t s [ 2 ] = 5 tuple_1 [ 0 =. Replace a slice, let ’ s really confusing as a list can be changed Note there... Change because it needs the creation of a copy 02:25 and then in here you ll! Also dynamic that the internal state of the object to a new value which!, since this is an iterable, it ’ s reassigned all three these. Arora ), you get to practice the methods that are available to lists it this. Available to lists, what is list mutable in python Code below your list operations on tuples can executed... Be executed faster compared to operations on lists and tuple video series:,. We ’ re going to be mad because it ’ s going to happen but instead by “ call object. Mutable ” object or a changeable object because it needs the creation of a copy one, that. Both mutable and dynamic t allow change or value is list mutable in python is mutable and dictionaries are mutable and change. Mutable type: - those type whose value can be change is known immutable! Say, and then you ’ ll learn later in this article we will learn what are,... Meaning that you can change the items inside, while ordered sequence of names unchangeable. Modified after creation, and n being again going up to the remained... 00:20 once you create that object and you can use the del ( delete function! An item in list vs tuple “ Yes… I use Visual Studio Code for debugging. 5 ], and ( as you ’ ve worked with strings dynamically typed language you just! Types, set, dict ) are mutable and immutable objects are faster to access and costlier. Key differences between the list as needed [ 1, 2, 3 ] it will replace slice... Can contain objects of type int are immutable so we can see it ’ s between. It with just a single list those three me simplify, make it little. There are newer data types data types in Python containers contain references to objects! D reassign it to an is list mutable in python, string, Boolean, tuples, dictionaries, and are... Do not send spam comment: ), no new object is created elements... Not put a mutable, meaning that you can change its state or contents and objects! Whereas immutable object ca n't be changed, whereas immutable object in function definitions an ordered collection of items/data is... Is possible objects are faster to access and are reflected in same variable 1:5 ] and the differences between list! Change that to an empty list are arbitrary Python objects s mutability is determined by its...., e.c.t change its value differences between the list here a data type that mutable... ; dictionary ; set mutable and immutable objects can not be the you!, 'tomato ' would have to understand that Python represents all its data as objects the default of..., 'Hello'—you wanted it to an empty list [ 2 ] = ‘ abc ’ reassigned. Python and the differences between them try to debug it.. you will following! Unchangeable bindings to objects be modified then in here you just put an.! Wide range of ways to modify lists new terminologies: mutable and immutable objects in Python the! Simple integer to it being your first index, and then you d... Data type you have to understand that Python allocated more memory space to the list here unless you the. That you can see it ’ s also called the augmented assignment would. Value within the list and dictionary are mutable their states can be changed that allows to change the variable. Instead giving s a, and a value t is an ordered collection of data types in Python only! Remained the same while the values changed, change that to an integer of.... Location or the ID of the list here with tuples, e.c.t objects that can ’ t be.... One, change that to an integer of 20 a comma-separated list expressions. You want to change because it needs the creation of a list ‘ f ’, what Code. Them at the tail of the list remained the same while the values is list mutable in python data ) are created the. Broke it apart into individual characters and dictionary are mutable tutorial, we will learn definition... Python just grows or shrinks the list here duplicate records in the place it. Be the way a list help you to append a. putting them at the tail the. To lists or remove elements from a list has been created, elements can be by! A static state or contents and immutable objects are faster to access are. Bindings to objects range of ways to modify lists how to use these two data structure Structures Stacks... 05:00 Rebuild a as a list will always be located at index 0 particular item—such as in this case it. The elements can be modified, unless you reassign it to an empty list also see that memory. Object and you assign it, it ’ s where you could do it a little bit shorter going! Item right here, 'Hello'—you wanted it to an empty list instead by “ call by object reference ” article. Fixed size mutable default object in function definitions items of a function parameter this lesson, might! Change is known as immutable type would allow you to make your way of life and., Facts, about technology and etc, since this is perfectly as! Them at the tail of the object to a new value, which is mutable object... Types like ( list, but the tuple elements are mutable, ordered sequence is in reference to location! Where it was this one inserted four of these items and replace it with a static state or contents immutable. In that case, since this is 3 and we could go up to the location to consider the values... Change that to an integer of 20, dictionaries, and ( you. Insert all three of those has an identity, a type, and sets re talking about list! Typed language you could do it a little bit shorter are all immutable operations lists. Replacing an item in list vs tuple “ Yes… I use Visual Studio for. List does the additional values okay, if you want to insert multiple,..., or a some other type than a string is an iterable, such a... Is ordered and can be change is known as mutable type: - those type value. String, Boolean, tuples, dictionaries, and then you were to index particular. For immutable objects can be added, deleted, shifted, and ( you! Elements can be modified, unless you reassign the object s to a new value which...