An IndexError is nothing to worry about. It\u2019s an error that is raised when you try to access an index that is outside of the size of a list. How do you solve this issue? Where can it be raised?
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In this article, we\u2019re going to answer those questions. We will discuss what IndexErrors are and how you can solve the \u201clist assignment index out of range\u201d error. We\u2019ll walk through an example to help you see exactly what causes this error.
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Without further ado, let\u2019s begin!<\/p>\n\n\n\n
When you receive an error message, the first thing you should do is read it. An error message can tell you a lot about the nature of an error.
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Our error message is: IndexError tells us that there is a problem with how we are accessing an index<\/a>. An index is a value inside an iterable object, such as a list<\/a> or a string. The message \u201clist assignment index out of range\u201d tells us that we are trying to assign an item to an index that does not exist. In order to use indexing on a list, you need to initialize the list. If you try to assign an item into a list at an index position that does not exist, this error will be raised.<\/p>\n\n\n\n The list assignment error is commonly raised in for<\/a> and while loops<\/a>. We\u2019re going to write a program that adds all the cakes containing the word \u201cStrawberry\u201d into a new array. Let\u2019s start by declaring two variables:<\/p>\n\n\n\n The first variable<\/a> stores our list of cakes. The second variable is an empty list that will store all of the strawberry cakes. Next, we\u2019re going to write a loop that checks if each value in \u201ccakes\u201d contains the word \u201cStrawberry\u201d. If a value contains \u201cStrawberry\u201d, it should be added to our new array. Otherwise, nothing will happen. Once our for loop has executed, the \u201cstrawberry\u201d array should be printed to the console. Let\u2019s run our code and see what happens:<\/p>\n\n\n\n As we expected, an error has been raised. Now we get to solve it!<\/p>\n\n\n\n Our error message tells us the line of code at which our program fails: The problem with this code is that we are trying to assign a value inside our \u201cstrawberry\u201d list to a position that does not exist. When we create our strawberry array, it has no values. This means that it has no index numbers. The following values do not exist: We are trying to assign values to these positions in our for loop. Because these positions contain no values, an error is returned. We can solve this problem in two ways.<\/p>\n\n\n\n First, we can add an item to the \u201cstrawberry\u201d array using append()<\/a>: The Our code works!<\/p>\n\n\n\nindexerror: list assignment index out of range.<\/code>
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<\/p>\n\n\n\nAn Example Scenario<\/h2>\n\n\n\n
<\/p>\n\n\n\ncakes = ["Strawberry Tart", "Chocolate Muffin", "Strawberry Cheesecake"]\nstrawberry = []<\/pre><\/div>\n\n\n\n
<\/p>\n\n\n\nfor c in range(0, len(cakes)):\n\tif "Strawberry" in cakes[c]:\n\t\tstrawberry[c] = cakes[c]\n\nprint(strawberry)<\/pre><\/div>\n\n\n\n
Traceback (most recent call last):\n File "main.py", line 6, in <module>\n\tstrawberry[c] = cakes[c]\nIndexError: list assignment index out of range<\/pre><\/div>\n\n\n\n
The Solution<\/h2>\n\n\n\n
<\/p>\n\n\n\nstrawberry[c] = cakes[c]<\/pre><\/div>\n\n\n\n
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<\/p>\n\n\n\nstrawberry[0]\nstrawberry[1]\n\u2026<\/pre><\/div>\n\n\n\n
<\/p>\n\n\n\nSolution with append()<\/h3>\n\n\n\n
<\/p>\n\n\n\ncakes = ["Strawberry Tart", "Chocolate Muffin", "Strawberry Cheesecake"]\nstrawberry = []\n\nfor c in range(0, len(cakes)):\n\tif "Strawberry" in cakes[c]:\n\t\tstrawberry.append(cakes[c])\n\nprint(strawberry)<\/pre><\/div>\n\n\n\n
append()<\/code> method adds an item to an array and creates an index position for that item. Let\u2019s run our code: [\u2018Strawberry Tart\u2019, \u2018Strawberry Cheesecake\u2019].
<\/p>\n\n\n\nSolution with Initializing an Array<\/h3>\n\n\n\n