Converting String to Float in Python

Learn how to convert string representations of numbers to their corresponding float values using Python’s built-in functions. …

Learn how to convert string representations of numbers to their corresponding float values using Python’s built-in functions.

Definition of the Concept

In Python, a string is a sequence of characters enclosed within quotes. On the other hand, a float is a numeric data type used to represent decimal numbers. When you have a string that represents a number, but it’s not a numeric value itself, you need to convert it into a float so that you can perform mathematical operations on it.

Step-by-Step Explanation

Converting a string to a float in Python involves the following steps:

1. Identify the String

First, identify the string you want to convert into a float. This could be any string representation of a number, such as '123', '-45.67', or '3.14e-2'.

# Example string
number_str = '12'

2. Use the Built-in float() Function

Next, use Python’s built-in float() function to convert the string into a float value. This function takes any string that represents a number and returns its corresponding float value.

# Convert string to float using float()
number_float = float(number_str)

3. Perform Mathematical Operations (Optional)

Now that you have converted your string into a float, you can perform various mathematical operations on it, such as addition, subtraction, multiplication, division, and more.

# Example usage: Add two numbers
num1 = float('12')
num2 = float('5')

result = num1 + num2

print(result)  # Output: 17.0

Code Snippets and Explanation

Here are some additional code snippets that demonstrate how to convert string to float in Python:

Converting Multiple Strings

You can also convert multiple strings into floats using a loop or list comprehension.

# Example usage: Convert multiple strings into floats
strings = ['12', '45.67', '3.14e-2']

floats = [float(s) for s in strings]

print(floats)  # Output: [12, 45.670000000000004, 0.0314]

Handling Non-Numeric Strings

What happens when you try to convert a non-numeric string into a float? Python raises a ValueError.

# Example usage: Handle non-numeric strings
try:
    number_str = 'abc'
    float(number_str)
except ValueError as e:
    print(e)  # Output: could not convert string to float

Conclusion

Converting a string to a float in Python is a straightforward process that involves using the built-in float() function. With this guide, you should now be able to confidently convert string representations of numbers into their corresponding float values and perform various mathematical operations on them. Happy coding!