In Python, you can get the last digit of an integer in the following ways:

## Using Modulo Operator

You can use the modulo operator (`%`

) to get the last digit of an integer in the following way:

- Convert number to absolute form;
- Get the last digit by calculating
`number % 10`

; - Add negative sign to the last digit if integer was negative.

The modulo operator in Python *won't* return the correct last digit for negative numbers because it performs floored division, and not truncated division. To get the correct result, you *must* convert the number to absolute form first (using `abs()`

), and then add the sign back.

For example:

def last_digit(num): last_digit_unsigned = abs(num) % 10 return -last_digit_unsigned if (num < 0) else last_digit_unsigned print(last_digit(0)) # 0 print(last_digit(1234)) # 4 print(last_digit(-1234)) # -4

As an alternative, you may use the following mathematical formula for calculating remainder correctly:

def last_digit(num): return num - (10 * int(num / 10)) print(last_digit(0)) # 0 print(last_digit(1234)) # 4 print(last_digit(-1234)) # -4

This performs truncated division (i.e. using the `int()`

method, the fraction part is removed/truncated from the result of the division).

This works in the following way:

# num = 1234 # last_digit = 1234 - (10 * int(1234 / 10)) # last_digit = 1234 - (10 * int(123.4)) # last_digit = 1234 - (10 * 123) # last_digit = 1234 - 1230 # last_digit = 4

## Converting to String and Retrieving Last Character

You could do the following:

- Convert the integer to a string;
- Get the last character of the string;
- Convert the string back to integer;
- Add negative sign to the last digit if integer was negative.

def last_digit(num): num_str = str(num) last_digit_unsigned = int(num_str[-1]) return -last_digit_unsigned if (num < 0) else last_digit_unsigned print(last_digit(0)) # 0 print(last_digit(1234)) # 4 print(last_digit(-1234)) # -4

When the integer is converted to a string, the sign is considered a character in the string and has *no* special meaning, which is why it is *not* added to the last digit. For this reason, the sign is added back once the last character is converted back to an integer.

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