How to convert a string to a float in Python

How to convert a string to a float in Python.

Here is a detailed step-by-step tutorial on how to convert a string to a float in Python:

Step 1: Understand the concept

Converting a string to a float means converting a sequence of characters (string) that represents a numerical value with a decimal point into a floating-point number. This allows you to perform mathematical operations on the converted value.

Step 2: Identify the string

First, you need to identify the string that you want to convert to a float. It can be stored in a variable or directly provided as input.

Step 3: Use the float() function

Python provides a built-in function called float() that converts a string to a float. You need to pass the string as an argument to this function.

Example 1: Converting a string variable to a float

# Assign a string to a variable
string_num = "3.14"

# Convert the string to a float
float_num = float(string_num)

# Print the float value
print(float_num)

Output:

3.14

Example 2: Converting a user input string to a float

# Get user input as a string
string_input = input("Enter a floating-point number: ")

# Convert the string to a float
float_num = float(string_input)

# Print the float value
print(float_num)

Output:

Enter a floating-point number: 2.718
2.718

Step 4: Dealing with invalid conversions

It's important to handle cases where the string cannot be converted to a float. If the string contains non-numeric characters or is empty, a ValueError will be raised. You can use exception handling to gracefully handle these situations.

Example 3: Handling invalid conversions

# Get user input as a string
string_input = input("Enter a floating-point number: ")

try:
    # Convert the string to a float
    float_num = float(string_input)
    # Print the float value
    print(float_num)
except ValueError:
    print("Invalid input. Please enter a valid floating-point number.")

Output 1:

Enter a floating-point number: 3.14
3.14

Output 2:

Enter a floating-point number: abc
Invalid input. Please enter a valid floating-point number.

By following these steps, you can easily convert a string to a float in Python. Remember to handle invalid conversions using exception handling to ensure your program doesn't crash.