In this article, we will guide you through how to parse a string to a float or integer using Python.

What is Parsing?

Parsing is the process of converting a string representation of a value to its corresponding data type. In Python, we have two primary data types: float and integer. When we receive input from a user or read data from a file, it’s often in the form of a string. To perform any mathematical operation on this input, we need to convert it to a numerical data type. This is where parsing comes in handy.

How to Parse a String to a Float

In Python, we can parse a string to a float using the float() function. The float() function takes a single parameter, which is the string we want to convert to a float. Here’s an example:

				
					string_num = "3.14"
float_num = float(string_num)

In this example, we have a string representation of a float, “3.14”, which we convert to a float using the float() function. The resulting float is assigned to the variable float_num.

It’s essential to note that if the string cannot be converted to a float, a ValueError exception will be raised. For example, trying to convert the string “hello” to a float will raise a ValueError.

How to Parse a String to an Integer

In Python, we can parse a string to an integer using the int() function. The int() function takes a single parameter, which is the string we want to convert to an integer. Here’s an example:

				
					string_num = "42"
int_num = int(string_num)

In this example, we have a string representation of an integer, “42”, which we convert to an integer using the int() function. The resulting integer is assigned to the variable int_num.

Similar to parsing a string to a float, if the string cannot be converted to an integer, a ValueError exception will be raised. For example, trying to convert the string “hello” to an integer will raise a ValueError.

Parsing a String with a Decimal Point to an Integer

What if you have a string representation of a number that has a decimal point, but you want to convert it to an integer? In this case, you would need to remove the decimal point first before parsing the string to an integer. Here’s an example:

				
					string_num = "3.14"
int_num = int(string_num.replace(".", ""))

In this example, we first replace the decimal point with an empty string using the replace() method. The resulting string, “314”, is then parsed to an integer using the int() function.

Handling Errors When Parsing Strings

As mentioned earlier, trying to parse a string that cannot be converted to a numerical data type will raise a ValueError exception. To handle this error, we can use a try-except block. Here’s an example:

				
					string_num = "hello"
try:
    float_num = float(string_num)
    int_num = int(string_num)
except ValueError:
    print("The string cannot be converted to a float or integer.")

In this example, we first replace the decimal point with an empty string using the replace() method. The resulting string, “314”, is then parsed to an integer using the int() function.


Thanks for reading. Happy coding!