What does abs do in Python?

Question

I don't understand how the following code works:

#CodingBat.com Warmup 7
#Given an int n, return True if it is within 10 of 100 or 200. 

def near_hundred(n):
    return ((abs(100 - n) <= 10) or (abs(200 - n) <= 10))

What does "abs()" do? And how does this work to solve the problem above?

Answer 1

Inbuilt function abs() returns the absolute value of a number. (The numerical value without regard to its sign)

abs(-1) #Returns 1
abs(1)  #Also returns 1

Answer 2

You can find out by typing abs in the interactive prompt:

>>> abs
<built-in function abs>
>>> help(abs)
abs(...)
    abs(number) -> number

    Return the absolute value of the argument.

In other words abs is a built-in function defined such that abs(x) gives the absolute value of x. This means that if x is positive it returns x, otherwise -x. Another way of saying it is that it returns the value of x without the sign.

In your example abs(100 - n) is the difference between n and 100 expressed as a positive number. You can think of it as the distance between n and 100.

Answer 3

What about this:

1. Built-in Functions

The Python interpreter has a number of functions built into it that are always available. They are listed here in alphabetical order.

abs(x)

Return the absolute value of a number. The argument may be a plain or long integer or a floating point number. If the argument is a complex number, its magnitude is returned.

[...]

http://docs.python.org/library/functions.html?highlight=abs#abs

Answer 4

this will return absolute value of a number: http://www.tutorialspoint.com/python/number_abs.htm

Answer 5

It says what it does in your code sample...

#Note: abs(num) computes the #absolute value of a number.