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What does the str_to_num function in the code snippet do?
What exception is caught if the conversion of the string to an integer fails in the str_to_num function?
What role does the try-except block play in the str_to_num function?
How does the str_to_num function deal with a string that cannot be converted to either an integer or a float?
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What is emphasized as a benefit of using conversion functions and try-except blocks in Python?
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What is the correct syntax for creating a string literal that spans multiple lines?
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How are individual characters in a string accessed in Python?
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What does the + operator do when applied to strings in Python?
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Study Notes
#!python
## Type Casting in Python
Type casting is one of the fundamental concepts in programming languages. It allows us to convert data from one type to another. In Python, we can achieve this through built-in functions like `int()`, `float()`, `str()`, etc. However, these functions work best with specific types of input. Let's explore how we can handle more complex cases using the `type()` function.
The `type()` function returns the type of its operand. Here's an example:
```python
print(type("Hello"))
Output:
<class 'str'>
In the above code, the type() function is used to print the type of the string "Hello". The output shows that it is of type str. Similarly, if you want to find out the type of any variable, you can use this function.
However, converting a value into a different data type doesn't always go smoothly. For instance, when trying to convert a non-numeric string into an integer, Python raises a ValueError exception. To avoid this, you can use the following code snippet:
try:
i = int('abc')
except ValueError:
try:
f = float('abc')
except ValueError:
s = str('abc')
This code block attempts to cast a string value to integers and floats, respectively. If either fails, it defaults to strings.
Another way to perform conversions without raising errors is by catching the exceptions using try...except blocks. This approach provides more control over how to handle potential conversion errors. Here's an example:
def str_to_num(string):
try:
num = int(string)
except ValueError:
try:
num = float(string)
except ValueError:
num = string
return num
In this code snippet, we define a function called str_to_num which takes a string parameter. Inside the function, we attempt to convert the string to an integer. If the conversion fails, we catch the ValueError exception and then try to convert the string to a float. If that also fails, we catch the ValueError exception again and treat the string as a string. Finally, we return the converted value.
In conclusion, the type() function is a powerful tool in Python for understanding and manipulating data types. It allows us to perform type casting in a controlled and efficient manner. By using try-except blocks and custom conversion functions, we can handle complex conversions and ensure that our programs run smoothly.
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Description
Learn about type casting and data type conversions in Python. Explore built-in functions like int(), float(), and str(), as well as the type() function for determining variable types. Discover how to handle conversion errors using try...except blocks and custom conversion functions.
