Calculations

doing math with Python

Arithmetical operations

We can do arithmetic with Python:

print(1 + 2) # 3.0
print(2 - 1) # 1.0
print(3 * 2) # 6.0
print(9 / 3) # 3.0

Python (version 2.7+) converts all integers to floats!

Also, division by zero can result in a ZeroDivisionError!

Calculations with variables

Predictably, we can also do mathematics with variables in Python:

speed_limit = 55
my_speed = speed_limit * 2
print(my_speed) # 110.0

Other operators

Exponents

To denote "to the power of", we use the notation **

print(3 ** 2) # 9.0 (3 squared)
print(2 ** 5) # 32.0 (2 to the power of 5)
print(9 ** 0.5) # 3.0 (square root of 9) 

Modulo

To denote "the remainder of", we use the notation % (as seen as in JavaScript)

print(17 % 4)  # 1.0
print(9 % 9)   # 0.0
print(32 % -7) # -3.0

Updates (plus-equals)

To write x = x + 1 to mean "add one to the variable x ", we can use the shorthand +=:

x = 1
print (x += 1) # aka x = x + 1 = 2.0

Predictably, we can combine -, *, /, and % with = as well:

x = 3
print (x -= 2) # 1.0
print (x *= 2) # 6.0
print (x /= 2) # 1.5