How to Convert a String to an Integer in Python
In Python, converting a string to an integer is a common task, especially when dealing with user input or data parsing. The simplest and most direct way to do this is by using the built-in int()
function.
1. Using the int()
Function
The int()
function takes a string as input and converts it into an integer. Here’s an example:
number_string = "123"
number = int(number_string)
print(number) # Output: 123
This converts the string "123"
into the integer 123
.
2. Handling Invalid Input
If the string contains non-numeric characters, int()
will raise a ValueError
. To handle this, use try
and except
blocks:
try:
number = int("123abc")
except ValueError:
print("Invalid input, cannot convert to integer.")
This way, you avoid crashing your program when an invalid string is passed.
3. Converting Different Number Formats
You can also convert strings representing numbers in different formats, like binary, hexadecimal, or octal, by specifying the base as the second argument of int()
.
- Binary to Integer:
binary_string = "1010"
number = int(binary_string, 2)
print(number) # Output: 10
- Hexadecimal to Integer:
hex_string = "1A"
number = int(hex_string, 16)
print(number) # Output: 26
4. Using float()
for Decimals
If the string represents a decimal number and you want to preserve the decimal value, use float()
instead of int()
:
decimal_string = "123.45"
number = float(decimal_string)
print(number) # Output: 123.45
Note that int()
will truncate the decimal part when converting:
number = int(float(decimal_string))
print(number) # Output: 123
Conclusion
Converting a string to an integer in Python is straightforward using the int()
function. Always ensure that your input is valid or handle errors with try-except
blocks. By understanding these fundamentals, you can handle various numeric string formats in your Python applications.
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