Part 06 - Operators

Mathematical

Name

Syntax example

Comments

Multiplication

a * b

Division

a / b

Remainder

a % b

Often called mod or modulus

Addition

a + b

Subtraction

a - b

Exponent

a ** b

Do not confuse this with Bitwise Xor ^

Bitshift Right

a >> b

Bitshift Left

a << b

Bitwise And

a & b

Bitwise Or

a | b

Bitwise Xor

a ^ b

The mathematical operators can also be used in the syntax a <operator>= b, for example, a += b.
This is merely a shortcut for a = a <operator> b, or in our example a = a + b.

Relational and Logical

Name

Syntax Example

Comments

Less Than

a < b

Greater Than

a > b

Less Than or Equal To

a <= b

Greater Than or Equal To

a >= b

Equality

a == b

Inequality

a != b

Logical And

a and b

Only use when a and b are boolean values

Logical Or

a or b

Only use when a and b are boolean values

Logical Not

not a

Only use when a is a boolean value

Types

Name

Syntax Example

Comments

Typecast

a cast string

Typecast

a as string

Type Equality/Compatibility

a isa string

Type Retrieval

typeof(string)

Type Retrieval

a.GetType()

Primary

Name

Syntax Example

Comments

Member

A.B

Classes are described in Part 08 - Classes

Function Call

f(x)

Functions are described in Part 07 - Functions

Post Increment

i++

See Difference between Pre and Post Increment/Decrement

Post Decrement

i--

See Difference between Pre and Post Increment/Decrement

Constructor Call

o = MyClass()

Classes are described in Part 08 - Classes

Unary

Name

Syntax Example

Comments

Negative Value

-5

Pre Increment

++i

See Difference between Pre and Post Increment/Decrement

Pre Decrement

--i

See Difference between Pre and Post Increment/Decrement

Grouping

(a + b)

Difference between Pre and Post Increment/Decrement

When writing inline code, Pre Increment/Decrement (+i/-i) commit the action, then return its new value, whereas Post Increment/Decrement (i+/i-) return the current value, then commit the change.

num = 0
for i in range(5):
    print num++
print '---'
num = 0
for i in range(5):
    print ++num
0
1
2
3
4
---
1
2
3
4
5

To make your code more readable, avoid using the incrementors and decrementors.
Instead, use i += 1 and i -= 1.

Exercises

  1. Put your hands on a wall, move your left foot back about 3 feet, move the right foot back 2 feet.

Go on to Part 07 - Functions