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In Python,converting a string to an integer is important for performing mathematical operations, processing user input and efficiently handling data. This article will explore different ways to perform this conversion, includingerror handlingand other method to validate input string during conversion.

Using int() Function

The simplest way to convert a string to an integer in Python is by using the int() function. This function attempts to parse the entire string as a base-10 integer.

Python

s="42"num=int(s)print(num)

Output

Explanation: The int() function takes the strings and converts it into an integer.

Note:

If the string contains non-numeric characters or is empty,int() will raise aValueError.
int()function automatically handlesleading andtrailingwhitespaces, so int() function trims whitespaces and converts the core numeric part to an integer.

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Frequently Asked Questions

Converting Strings with Different Bases

Theint() function also supports other number bases, such as binary (base-2) or hexadecimal (base-16). To specify the base during conversion, we have to provide the base in the second argument of int().

Python

# Binary strings="1010"num=int(s,2)print(num)# Hexadecimal strings="A"num=int(s,16)print(num)

Output

Explanation:

Here, int(s, 2) interpretssas a binary string, returning10 in decimal.
Similarly,int(s, 16) treatss as a hexadecimal string.

Handling Invalid Input String

Using try and except

If the input string contains non-numeric characters,int()will raise aValueError. To handle this gracefully, we use atry-exceptblock.

Python

s="abc"try:num=int(s)print(num)exceptValueError:print("Invalid input: cannot convert to integer")

Output

Invalid input: cannot convert to integer

Explanation:

try attempts to convert the strings to an integer.
Ifs contains non-numeric characters, aValueError is raised and we print an error message instead.