How Do I Change Data Type?


Angela Bailey

Changing the data type of a variable is a common task in programming. It allows you to convert data from one type to another, which can be useful in various scenarios. In this tutorial, we will explore different methods to change the data type.

Method 1: Using Type Casting

Type casting is a technique that allows you to explicitly convert one data type to another. It involves specifying the desired data type before the variable you want to convert. Here’s an example:

num = 10
float_num = float(num)
print(float_num) # Output: 10.0

In the above code snippet, we have converted an integer (`num`) to a floating-point number (`float_num`). The `float()` function performs the conversion.

Important points to remember:

– Type casting may lead to loss of precision or truncation of data.
– Not all conversions are possible. For example, converting a string containing letters into an integer will result in an error.

Method 2: Using Built-in Conversion Functions

Some programming languages provide built-in functions that allow you to directly change the data type without using type casting explicitly. These functions are designed specifically for certain conversions and can handle edge cases more effectively.

Here’s an example using Python’s built-in conversion functions:

str_num = “100”
int_num = int(str_num)
print(int_num) # Output: 100

In the code above, we used the `int()` function to convert a string (`str_num`) into an integer (`int_num`).

Method 3: Parsing and Formatting

Parsing and formatting refer to extracting specific parts of a string or rearranging its structure according to a defined format. This technique is commonly used when dealing with strings that represent dates or numbers in different formats.

Let’s consider an example in JavaScript:

var dateStr = “2022-01-01”;
var parsedDate = new Date(dateStr);
console.log(parsedDate); // Output: Sat Jan 01 2022 00:00:00 GMT+0530 (India Standard Time)

In the code above, we used the `Date` object constructor to parse a date string (`dateStr`) into a JavaScript `Date` object (`parsedDate`). This allows us to use various methods and properties available for handling dates.

Method 4: Custom Conversion Functions

If none of the built-in conversion methods work for your specific requirements, you can create custom conversion functions. These functions can contain complex logic to convert the data type.

Here’s an example in Python:

def str_to_bool(str_val):
if str_val.lower() == “true”:
return True
return False

bool_val = str_to_bool(“True”)
print(bool_val) # Output: True

In the code snippet, we created a custom function `str_to_bool()` that converts a string (`str_val`) to a boolean value. The function checks if the string is equal to “true” (case-insensitive) and returns `True` or `False` accordingly.

  • Type casting is useful when you need a quick and simple conversion.
  • Built-in conversion functions are more specialized and handle edge cases effectively.
  • Parsing and formatting are useful when dealing with strings that represent dates or numbers in different formats.
  • Custom conversion functions allow you to create conversions tailored to your specific needs.


Changing the data type of variables is an essential skill for programmers. It allows you to manipulate and process data effectively.

In this tutorial, we explored various methods to change the data type, including type casting, built-in conversion functions, parsing and formatting, and custom conversion functions. Each method has its own advantages and use cases. Understanding these techniques will help you write more efficient and flexible code in your programming journey.

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