✓ Boolean Expressions
>>> 5 == 5 True >>> 5 == 6 False> >> type(True) <type 'bool'> >>> type(False) <type 'bool'>
✓ Relational operators
x != y x > y x < y x >= y x <= y
✓ Logical Operators – There are three logical operators: and, or, and not.
n%2 == 0 or n%3 == 0 true if either of the conditions is true >>> 6 and True # Any nonzero number is interpreted as true True
✓ Conditional execution
if x < y: print 'x is less than y' elif x > y: print 'x is greater than y' else: print 'x and y are equal'
✓ Nested conditionals
if 0 < x: if x < 10: print 'x is a positive single-digit number.'
✓ Recursion – It is legal for one function to call another, and it is also legal for a function to call itself.
def countdown(n): if n <= 0: print 'Blastoff!' else: print n countdown(n-1)
✓ Keyboard Input
>>> prompt = 'What...is the airspeed velocity of an unladen swallow?\n' >>> speed = raw_input(prompt) What...is the airspeed velocity of an unladen swallow? 17 >>> int(speed) 17