{"id":773,"date":"2020-10-26T03:33:30","date_gmt":"2020-10-26T03:33:30","guid":{"rendered":"https:\/\/www.pythontutorial.net\/?page_id=773"},"modified":"2025-03-27T13:22:35","modified_gmt":"2025-03-27T13:22:35","slug":"dynamic-typing-in-python","status":"publish","type":"page","link":"https:\/\/www.pythontutorial.net\/advanced-python\/dynamic-typing-in-python\/","title":{"rendered":"Dynamic Typing in Python"},"content":{"rendered":"\n

Summary<\/strong>: in this tutorial, you’ll learn about dynamic typing in Python and how it works.<\/p>\n\n\n\n

Introduction to dynamic typing in Python #<\/a><\/h2>\n\n\n\n

In some programming languages such as Java or C#, when declaring a variable<\/a>, you need to specify a data type for it.<\/p>\n\n\n\n

For example, in Java, you can declare a variable<\/a> with the type String<\/code> and initializes its value as follows:<\/p>\n\n\n

String<\/span> message = \"Hello\"<\/span>;<\/code><\/span>Code language:<\/span> JavaScript<\/span> (<\/span>javascript<\/span>)<\/span><\/small><\/pre>\n\n\n
Behind the scenes, Java creates a new String<\/code> object whose value is \"Hello\"<\/code>. It also creates a variable called message<\/code> with type String<\/code> and references the message<\/code> variable to the String<\/code> object.<\/p>\n\n\n\n
In statically typed languages, the data types are associated with variables.<\/p>\n\n\n\n
Later, if you assign an integer to the message<\/code> variable, it’s not going to work. The reason is that the message<\/code> variable is already associated with the String type, not the integer type.<\/p>\n\n\n\n
Unlike statically typed languages, Python is a dynamically typed language. When declaring a variable in Python, you don’t specify a type for it:<\/p>\n\n\n
message = 'Hello'<\/span><\/code><\/span>Code language:<\/span> JavaScript<\/span> (<\/span>javascript<\/span>)<\/span><\/small><\/pre>\n\n\n
In Python, the message<\/code> variable is just a reference to an object which is a string. There is no type associated with the message<\/code> variable.<\/p>\n\n\n
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\"\"<\/figure>\n<\/div>\n\n\n
If you assign a number to the message<\/code> variable, it’s perfectly fine:<\/p>\n\n\n
message = 100<\/code><\/span><\/pre>\n\n\n
In this case, Python creates a new integer object, and the message<\/code> references to the new integer object:<\/p>\n\n\n
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\"\"<\/figure>\n<\/div>\n\n\n
To determine the type of object that a variable currently references, you use the type()<\/code> function.<\/p>\n\n\n\n
The following example defines a variable named message<\/code> and assigned it a string 'Hello'<\/code>:<\/p>\n\n\n
message = 'Hello'<\/span>\nprint<\/span>(type(message))<\/code><\/span>Code language:<\/span> PHP<\/span> (<\/span>php<\/span>)<\/span><\/small><\/pre>\n\n\n
Output:<\/p>\n\n\n
<class<\/span> 'str<\/span>'><\/span><\/code><\/span>Code language:<\/span> HTML, XML<\/span> (<\/span>xml<\/span>)<\/span><\/small><\/pre>\n\n\n
When you assign a number to the message<\/code> variable, type of the object that the message<\/code> variable references by also changes:<\/p>\n\n\n
message = 100<\/span>\nprint<\/span>(type(message))<\/code><\/span>Code language:<\/span> PHP<\/span> (<\/span>php<\/span>)<\/span><\/small><\/pre>\n\n\n
Output:<\/p>\n\n\n
<class<\/span> 'int<\/span>'><\/span><\/code><\/span>Code language:<\/span> HTML, XML<\/span> (<\/span>xml<\/span>)<\/span><\/small><\/pre>\n\n\n
Summary #<\/a><\/h2>\n\n\n\n
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  • Python is a dynamically typed language.<\/li>\n\n\n\n
  • In Python, variables don’t associate with any particular types.<\/li>\n\n\n\n
  • Use the type()<\/code> function to get the type of the objects that variables reference.<\/li>\n<\/ul>\n
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Try it<\/a><\/p>\n\n\n\n
Try it<\/a><\/p>\n\n\n\n