Find variable type python

How to find Variable type in Python?

In this article, we will learn how to find the type of a variable in Python no matter what is stored in that variable. The variable can have a list, some class object, string, number, tuple, or anything else.

We use the type() function to find the type of any variable in Python.

How to find Variable type in Python?

Python type() Function

This function has a very simple syntax and can be used to find the type of any variable in Python be it a collection type variable, a class object variable, or a simple string or integer. Below is the syntax,

Let’s take an example for different datatypes and see the output.

Let’s take another example,

In Python 2.x version, the output for the above code will be , but from Python 3.x onwards, there is only one datatype which is int , which is equivalent to long of python 2.x version.

For a literal sequence of characters or a string variable,

a = 'Hello World!' print(type(a))

If you want to get the name of the datatype only then you can use the __name__ attribute along with the type() function. Below we have an example for that too.

a = '3.14159' print(type(a).__name__)

The code examples till now were about basic datatypes, now let’s see a few code examples for list, tuples, etc.

my_list = [1, 2, 3, 4] my_tuple = (1, 2, 3, 4) print(type(my_list)) print(type(my_tuple)) 

Using type() function for User-defined Class Objects

Now let’s try and use the type() function for identifying the type for any object of a custom class and see if it returns the correct value.

class Studytonight: # init method def __init__(self): print("Object initialised") st = Studytonight() print(type(st))

So, we can use the type() function to find the type of all kinds of variable objects.

Conclusion

We have explored various methods to find variable types in Python. From using the type() function to leveraging the isinstance() function and the introspection capabilities of the built-in inspect module, we have covered recommended approaches for type identification. Additionally, we have discussed the importance of understanding Python’s dynamic typing system and the potential challenges it presents.

As you continue your Python programming journey, remember to leverage the techniques discussed in this article to accurately determine variable types. Understanding the data you are working with is key to writing robust, maintainable, and efficient code.

If you face any problem while executing any of the above code examples, or if have any doubts, post them in the comments. We would be more than happy to help.

Frequently Asked Questions(FAQs)

1. How can I determine the type of a variable in Python?

You can use the type() function to determine the type of a variable in Python. For example, type(my_variable) will return the type of the variable my_variable.

2. Can I check if a variable is of a specific type in Python?

Yes, you can use the isinstance() function to check if a variable is of a specific type. It takes two arguments: the variable and the type you want to check. For example, isinstance(my_variable, int) will return True if my_variable is an integer.

3. Are there any libraries in Python that assist with type identification?

Yes, Python’s built-in inspect module provides functions like inspect.ismodule(), inspect.isfunction(), and inspect.isclass(), which allow for more advanced type identification and introspection.

4. Does Python have a feature similar to static typing or type annotations?

Yes, Python 3 introduced the concept of type annotations, allowing you to hint the expected types of variables. However, type annotations are not enforced by the interpreter and serve primarily as documentation and tooling aids.

5. Can the type of a variable change during runtime in Python? A5: Yes, Python is a dynamically typed language, which means the type of a variable can change during runtime. Variables can be reassigned to values of different types, and function arguments can accept values of different types.

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Как узнать тип переменной Python

В Python есть две функции type() и isinstance() с помощью которых можно проверить к какому типу данных относится переменная.

Разница между type() и isinstance()

type() возвращает тип объекта

isinstance() возвращает boolean значение — принадлежит объект данному типу или нет

type()

Встроенная функция type() это самый простой способ выяснить тип объекта. В Python всё является объектом, объекты делятся на изменяемые и неизменяемые .

Вы можете воспользоваться type() следующим образом.

Пример использования type()

В Python четырнадцать типов данных.

Для начала рассмотрим три численных типа (Numeric Types):

• int (signed integers)
• float (вещественные числа с плавающей точкой)
• complex (комплексные числа)

Создайте три переменные разного численного типа и проверьте работу функции:

var_int = 1380 var_float = 3.14 var_complex = 2.0-3.0j print (type(var_int)) print (type(var_float)) print (type(var_complex))

Рассмотрим ещё несколько примеров

# Text Type: var_str = ‘heihei.ru’ # Boolean Type: var_bool = True # Sequence Types: var_list = [ ‘heihei.ru’ , ‘topbicycle.ru’ , ‘urn.su’ ] var_tuple = ( ‘andreyolegovich.ru’ , ‘aredel.com’ ) var_range = range(0,9) print (type(var_str)) print (type(var_bool)) print (type(var_list)) print (type(var_tuple)) print (type(var_range))

Спецификацию функции type() вы можете прочитать на сайте docs.python.org

Команда type

Есть ещё полезная команда type которая решает другую задачу.

С помощью команды type можно, например, определить куда установлен Python.

Подробнее об этом можете прочитать здесь

python3 is hashed (/usr/bin/python3)

python3 is hashed (/usr/bin/python)

isinstance()

Кроме type() в Python есть функция isinstance(), с помощью которой можно проверить не относится ли переменная к какому-то определённому типу.

Иногда это очень удобно, а если нужно — всегда можно на основе isinstance() написать свою функцию.

Пример использования

Создадим пять переменных разного типа и проверим работу функции

var_int = 1380 var_str = ‘heihei.ru’ var_bool = True var_list = [ ‘heihei.ru’ , ‘topbicycle.ru’ , ‘urn.su’ ] var_tuple = ( ‘andreyolegovich.ru’ , ‘aredel.com’ ) if ( isinstance (var_int , int )): print ( f» < var_int >is int» ) else : print ( f» < var_int >is not int» ) if ( isinstance (var_str , str )): print ( f» < var_str >is str» ) else : print ( f» < var_str >is not str» ) if ( isinstance (var_bool , bool )): print ( f» < var_bool >is bool» ) else : print ( f» < var_bool >is not bool» ) if ( isinstance (var_list , list )): print ( f» < var_list >is list» ) else : print ( f» < var_list >is not list» ) if ( isinstance (var_tuple , tuple)): print ( f» < var_tuple >is tuple» ) else : print ( f» < var_tuple >is not tuple» )

1380 is int heihei.ru is str True is bool [‘heihei.ru’, ‘topbicycle.ru’, ‘urn.su’] is list (‘andreyolegovich.ru’, ‘aredel.com’) is tuple

Из isinstance() можно сделать аналог type()

Напишем свою фукнцию по определению типа typeof() на базе isinstance

def typeof(your_var): if ( isinstance (your_var, int)): return ‘int’ elif ( isinstance (your_var, bool)): return ‘bool’ elif ( isinstance (your_var, str)): return ‘str’ elif ( isinstance (your_var, list)): return ‘list’ elif ( isinstance (your_var, tuple)): return ‘tuple’ else : print(«type is unknown»)

Протестируем нашу функцию

Принадлежность к одному из нескольких типов

Если нужно проверить принадлежит ли объект не к какому-то одному, а к группе типов, эти типы можно перечислить в скобках.

Часто бывает нужно проверить является ли объект числом, то есть подойдёт как int, так и float

print ( isinstance ( 2.0 , ( int , float )))

Проверим несколько значений из списка

l3 = [ 1.5 , — 2 , «www.heihei.ru» ] for item in l3: print ( isinstance (item, ( int , float )))

Проверка списка или другого iterable

Часто бывает нужно проверить не одну переменную а целый список, множество, кортеж или какой-то другой объект.

Эту задачу можно решить с помощью isinstance() и функций:

Проверить все ли элементы списка l1 int

l1 = [ 1 , 2 , 3 ] if all ( map ( lambda p: isinstance (p, int ), l1)): print ( «all int in l1» )

Проверить несколько списков на int и float

l1 = [ 3 , — 4.0 , 5.5 , — 6.2 ] l2 = [ 1 , — 2 , «test» ] def verif_list (l): return ( all ( map ( lambda p: isinstance (p, ( int , float )), l))) if __name__ == «__main__» : print (verif_list(l1)) print (verif_list(l2))

Помимо isinstance() в Python есть функция issubclass() с помощью которой проверяется является один класс производным от другого.

В других языках

• Си: такой функции нет.
• C++: похожую задачу решает функция typeid()

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How to Check Type of Variable in Python

In this tutorial, we’ll learn about getting and testing the type of variables by using two different ways, and finally, we’ll know the difference between these two ways.

1. Checking Variable Type With Type() built-in function

what is type()

type() is a python built function that returns the type of objects

syntax

As you can see, in the above code we have many different variables,
now let’s get the type of these variables.

If you want to know all types of objects in python, you’ll find it in the final part of the article.

Example 2: checking if the type of variable is a string

let’s say that you want to test or check if a variable is a string, see the code bellow

As you can see, the code works very well, but this is not the best way to do that.
Remember!, if you want to check the type of variable, you should use isinstance() built function.

2. Checking Variable Type With isinstance() built-in function

what is isinstance()

The isinstance() is a built-in function that check the type of object and return True or False

sytnax

example 1: checking variables type

 #check if "list_var" is list print(isinstance(list_var, list)) #check if "string_var" is tuple print(isinstance(string_var, tuple)) #check if "tuple_var" is tuple print(isinstance(tuple_var, tuple)) #check if "dictionry_var" is dictionary print(isinstance(dictionry_var, dict)) 

if you want to get type of object use type() function.

if you want to check type of object use isinstance() function

4. Data Types in Python

Related Tutorials:

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Python Print Type of Variable – How to Get Var Type

Kolade Chris

If you’re a Python beginner, becoming familiar with all its various data types can be confusing at first. After all, there are a lot of them available to you in the language.

In this article, I’m going to show you how to get the type of various data structures in Python by assigning them to a variable, and then printing the type to the console with the print() function.

How to Print the Type of a Variable in Python

To get the type of a variable in Python, you can use the built-in type() function.

The basic syntax looks like this:

In Python, everything is an object. So, when you use the type() function to print the type of the value stored in a variable to the console, it returns the class type of the object.

For instance, if the type is a string and you use the type() on it, you’d get as the result.

To show you the type() function in action, I’m going to declare some variables and assign to them the various data types in Python.

name = "freeCodeCamp" score = 99.99 lessons = ["RWD", "JavaScript", "Databases", "Python"] person = < "firstName": "John", "lastName": "Doe", "age": 28 >langs = ("Python", "JavaScript", "Golang") basics =

I will then print the types to the console by wrapping print() around some strings and the type() function.

print("The variable, name is of type:", type(name)) print("The variable, score is of type:", type(score)) print("The variable, lessons is of type:", type(lessons)) print("The variable, person is of type:", type(person)) print("The variable, langs is of type:", type(langs)) print("The variable, basics is of type:", type(basics)) 

Here are the outputs:

# Outputs: # The variable, name is of type: # The variable, score is of type: # The variable, lessons is of type: # The variable, person is of type: # The variable, langs is of type: # The variable, basics is of type:

Final Thoughts

The type() function is a valuable built-in function of Python with which you can get the data type of a variable.

If you’re a beginner, you should save yourself the hassle of cramming data types by using the type() function to print the type of a variable to the console. This will save you some time.

You can also use the type() function for debugging because in Python, variables are not declared with data types. So, the type() function was built into the language for you to check for data types of variables.

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