Cast types in python

Understanding Python Type Casting: A Comprehensive Guide

Python is a high-level programming language that has become popular for its simplicity, readability, and versatility. One of the features of Python is type casting, which is the process of converting one data type into another. This guide aims to provide a comprehensive understanding of type casting in Python.

What is Type Casting?

Type casting, also known as type conversion, is a process in which data of one type is converted into another type. In Python, this can be achieved using functions such as int() , float() , and str() . For example, converting a floating-point number to an integer using int() or converting a string to a float using float() .

Why is Type Casting Important in Python?

Type casting is important in Python because different data types have different properties and functions associated with them. For example, integers can be used for mathematical operations, whereas strings can be used for text manipulation. By converting data from one type to another, we can perform operations that are specific to that data type.

Types of Type Casting in Python

In Python, there are two types of type casting: implicit type casting and explicit type casting.

Implicit Type Casting

Implicit type casting, also known as automatic type conversion, occurs when Python automatically converts one data type into another. This happens when a value of one type is assigned to a variable of another type.

For example, if we assign a floating-point number to an integer variable, Python will implicitly cast the floating-point number to an integer:

In this example, the floating-point number 10.5 is implicitly cast to an integer 10 when it is assigned to the integer variable y .

Explicit Type Casting

Explicit type casting, also known as manual type conversion, occurs when a programmer explicitly casts a value from one type to another using type casting functions.

For example, if we want to convert an integer to a floating-point number, we can use the float() function:

In this example, the integer 10 is explicitly cast to a floating-point number 10.0 using the float() function.

Type Casting in Python: Examples

Here are some examples of type casting in Python:

# Converting an integer to a floating-point number x = 10 y = float(x) print(y) # Converting a floating-point number to an integer x = 10.5 y = int(x) print(y) # Converting a string to an integer x = "10" y = int(x) print(y) # Converting a string to a floating-point number x = "10.5" y = float(x) print(y) # Converting an integer to a string x = 10 y = str(x) print(y) # Converting a floating-point number to a string x = 10.5 y = str(x) print(y)

Type Casting in Python: Common Issues

There are several common issues that arise when type casting in Python. Here are a few of the most common ones:

TypeError

A TypeError occurs when a type casting function is called with an argument that is not of the correct type. For example, if we try to convert a string that cannot be converted to an integer to an integer using the int() function, a TypeError will be raised:

TypeError: invalid literal for int() with base 10: 'hello'

In this example, the string «hello» cannot be converted to an integer, so a TypeError is raised.

ValueError

A ValueError occurs when a type casting function is called with an argument that is not a valid value for that type. For example, if we try to convert a string that cannot be converted to a floating-point number to a floating-point number using the float() function, a ValueError will be raised:

x = "hello" y = float(x) print(y)

ValueError: could not convert string to float: 'hello'

In this example, the string «hello» cannot be converted to a floating-point number, so a ValueError is raised.

Loss of Precision

When converting a floating-point number to an integer, there may be a loss of precision. This is because the decimal part of the floating-point number will be truncated, and only the integer part will be kept. For example:

In this example, the decimal part of the floating-point number 10.5 is lost when it is converted to an integer 10 .

Conclusion

In this guide, we have covered the basics of type casting in Python. We have discussed what type casting is, why it is important, and the different types of type casting. We have also seen several examples of type casting in action and some of the common issues that can arise when type casting. By understanding type casting, you will be able to write more efficient and versatile code in Python.

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What is Type Casting in Python?

Before learning about type casting in python, we should be familiar with the data types and data structures in python.

Data types in python are the classification or categorization of the data items (like numbers, integers, strings, etc). Data Types represent the kind of value and also tell what operations can be performed on a particular data (the data can be of any form). We have five built-in (general) data types in python namely — numeric, sequence type, boolean, set, and dictionary.

So, the conversion of one data type into the other data type is known as type casting in python or type conversion in python. Python supports a wide variety of functions or methods like: int() , float() , str() , ord() , hex() , oct() , tuple() , set() , list() , dict(), etc. for the type casting in python.

There are two varieties of typecasting in python namely — Explicit Conversion(Explicit type casting in python), and Implicit Conversion(Implicit type casting in python). The conversion of one data type into another, done via user intervention or manually as per the requirement, is known as explicit type conversion. On the other hand, in Implicit type conversion, Python automatically converts one data type to another data type without any user’s need; quite unique feature of Python language.

Why to Use Type-Casting in Python?

Let us take a real world example to understand the need of type casting in Python. Suppose a person is travelling to America from India and that person wants to buy something from a store in America. But that person only has cash in INR(Indian Rupees). So, the person goes to get their money converted from INR to USD (American Dollar) from a local bank in America. This analogy is simialr to what type casting in python is.

If we have a specified value or an object and we want to convert it into a string object, we use the str() method in python. Similarly, we use the float() method to convert a specified value or an object into a floating-point number or a floating object, and the int() method to convert an object into an integer value or an integer object.

So, to convert one data type into another data type, we use the typecasting in python.

There are two varieties of typecasting in python namely —

1. Explicit Conversion(Explicit type casting in python), and
2. Implicit Conversion(Implicit type casting in python).

Refer to the diagram shown below to understand the hierarchy of typecasting in python.

The conversion of one data type into another data type, done via developer or programmer intervention or manually as per the requirement, is known as explicit type conversion. It can be achieved with the help of Python’s built-in type conversion functions such as int() , float() , hex() , oct() , str() , etc .

Explicit type conversion is also known as Explicit Type Casting in Python or simply Type Casting in Python.

Let us now talk about implicit type casting in python. As we know that all data types in Python do not have the same level i.e. ordering of data types is not the same in Python. Data types have a certain ordering in which Python handles them. Some of the data types have higher-order, and some have lower order. While performing any operations on variables with different data types in Python, one of the variable’s data types will be changed to the higher data type. According to the level, one data type is converted into other by the Python interpreter itself (automatically). This is called, implicit type casting in python. Python converts a smaller data type to a higher data type to prevent data loss.

Examples of Type Casting

Let us now take a few examples to understand how various methods of typecasting in python work.

Addition of String and Integer Using Explicit Conversion

We can add a string and an integer in python. If we convert a string into an integer, we can add both integers to get the desired output. Let us see the example to understand how we can add a string and an integer in python using explicit conversion.

Syntax for conversion of string into integer:

Type Casting Int to Float

We can use the built-in float() method in python to convert an integer or string into a floating-point number. The float() method only accepts one parameter that is the value, which needs to be converted into a floating-point.

The syntax of float() method is very simple:

Let us take an example to understand the working of the float() method better. As we know a salary is a floating point number as it salary is added with a lot of allowances. So, we should convert the salary into floating-point number and then perform required operations.

Type Casting Float to Int

We can use the built-in int() method in python to convert a specified value or an object into an integer value or an integer object. The int() method accepts two parameters that are the value, which needs to be converted into an integer, and one base valve, which defines the number base. The base parameter is optional. The default value specified is 10 . The base-10 value simply resembles the number having base address 10 i.e. decimal numbers.

We can specify the base type of the number other than 10 such as

• 8 for octal number (to convert octal number into an equivalent decimal number).
• 16 for hexadecimal number (to convert a hexadecimal number into an equivalent decimal number).
• 2 for binary number (to convert the binary number into an equivalent decimal number).

The syntax of int() method is very simple:

Let us take an example to understand the working of the int() method better.

Type Casting Int to String

We can use the str() function in python to convert a specified value or an object into a string object.

The syntax of the str() method in python is very simple:

The str in python takes three parameters in which one of them is required and the other two are optional. The object is any object or value(s) that is to be converted into a string object. The encoding parameters stores the encoding of the provided object. The error stores the specified action that needs to be performed if the conversion or decoding fails.

Let us briefly discuss the parameters of str() function in python:

• Object: The object parameter is a required parameter. The object is any object or value(s) that is to be converted into a string object. If we do not provide any object in the parameter, the str in python returns an empty string.
• Encoding: The encoding parameters stores the encoding of the provided object. If we do not provide any encoding parameter, the default value i.e. UTF-8 is provided.
• Errors: The error stores the specified action that needs to be performed if the conversion or decoding fails. We can simply say that error is the response when decoding fails.

Let us take an example to understand the working of the float() method better.

Type Casting String to Int

As we have seen earlier, we can use the int() method in python to convert a string into an integer.

The value parameter is required but the base parameter is optional.

Let us take an example to see how a string is converted into an integer value in python.

Conclusion

• The conversion of one data type into the other data type is known as type casting in python or type conversion in python.
• Python supports a wide variety of functions or methods like: int() , float() , str() , ord(), hex() , oct() , tuple() , set() , list() , dict() , etc. for the type casting in python.
• There are two varieties of typecasting in python namely — Explicit Conversion (Explicit type casting in python), and Implicit Conversion (Implicit type casting in python).
• The conversion of one data type into another, done via user intervention or manually as per the requirement, is known as explicit type conversion .
• According to the level of data types, one data type is converted into other by the Python interpreter itself (automatically). This is called, implicit type casting in python.

Learn more :

Refer to the articles below to learn more about different topics that come under the typecasting in python:

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