More expressions (class slides)

CSc 110 More expressions

Review of previous expressions

Evaluate the expressions below:

4 * 4 / 2 % 2
( 2 + 3 ) / ( 2 - 1.5)
3**3 // 7
5**2 + 25**0.5

Review of previous expressions

Evaluate the expressions below:

4 * 4 / 2 % 2

0.0

( 2 + 3 ) / ( 2 - 1.5)

10.0

3**3 // 7

3

5**2 + 25**0.5

30.0

Comparisons

• What will be the result of the following expressions:

8 == 7
8 < 7
8 > 7

• What are the other two comparison operators?

Comparisons

Expressions with comparisons operators are evaluated to True or False

• == equal
• != different
• >= greater or equal
• > greater
• <= less or equal
• < less

Write a function

1. Its name is odd and it takes one integer argument n
2. It returns True if n is odd, False if n is even

print( odd(10) ) # False
print( odd(5) ) # True
print( odd(0) ) # False

Attendence

Submit your odd function as attendance on Gradescope.

Name your file odd.py

Write a function – solution

def odd(n):
  return n % 2 == 1

def main():
  print( odd(10) ) # False
  print( odd(5) ) # True
  print( odd(0) ) # False
  
main()

False
True
False

Comparisons

Expressions with comparisons operators are evaluated to True or False

• == equal
• != different
• >= greater or equal
• > greater
• <= less or equal
• < less

Evaluate the expressions

3**2 < 25**0.5
9 % 3 == 8 % 2
10 // 3 > 9 // 3
14 % 2 != 15 % 2

Evaluate the expressions

3**2 < 25**0.5

False

9 % 3 == 8 % 2

True

10 // 3 > 9 // 3

False

14 % 2 != 15 % 2

True

not

Expression	Result
not True	False
not False	True

and

Expression	Result
True and True	True
False and True	False
True and False	False
False and False	False

or

Expression	Result
True or True	True
False or True	True
True or False	True
False or False	False

and, or, not

• What will be the result of the following expressions:

not True

True and True
True or True

False and True
False or True

False and False
False or False

and, or, not

• What will be the result of the following expressions:

not True

False

True and True

True

True or True

True

False and True

False

False or True

True

False and False

False

False or False

False

Evaluation order

• (expressions...)

• ** : Exponentiation

• *, /, //, % : Multiplication, Division, Floor Division and Remainder

• +, - : Addition and subtraction

• <, <=, >, >=, !=, == : Comparisons

• not x : Boolean NOT

• and : Boolean AND

• or : Boolean OR

Evaluate the expressions

not 2**3 == 8 and 4 % 2 == 0
25*0.5 > 5**2 or 4 <= 2**2
4 % 2 == 0 or 4 // 0 == 0
4 % 2 != 1
not 0
not 1

Evaluate the expressions

not 2**3 == 8 and 4 % 2 == 0

False

25*0.5 > 5**2 or 4 <= 2**2

True

4 % 2 == 0 or 4 // 0 == 0

True

4 % 2 != 1

True

not 0

True

not 1

False