Think Python C2

Chapter 2: Variables, expressions and statements

Exercise 2.1

Numbers starting with a 0 are interpreted as being "octal" (or base-8). So 010 represents 8 (1 eights and 0 ones), and 011 is nine (1 eights and 1 ones). It can be sometimes be convenient to write computer-specific numbers in octal notation (such as UNIX file permissions), this is because 8 better fits the way computer memory is organized than normal decimal (base-10) notation.

Exercise 2.3

>>> width/2
8
>>> type(width/2)
<type 'int'>

>>> width/2.0
8.5
>>> type(width/2.0)
<type 'float'>

>>> 1+2*5
11
>>> type(1+2*5)
<type 'int'>

>>> delimiter*5
'.....'
>>> type(delimiter*5)
<type 'str'>

Exercise 2.4

#!/usr/bin/python

# 1. Sphere
r = 5
pi = 3.14159265
vol = (4.0/3.0)*pi*(r**3)

print vol

# 2. Books
book = 24.95*0.4
order = 60
shipping = (order - 1)*0.75+3
wholesale = book*order+shipping

print wholesale