2.0 Python: Numbers

There are three numeric types in Python:

1. int
2. float
3. complex

Varriables of numeric types are created when you assign a value to them:

x = 1       # int
y = 2.8     # float
z = 1j      # complex

To verify the type of any object in Python, use the type() function:

print(type(x))
print(type(y))
print(type(z))

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2.1 Int

Int or integer is a whole number, positive or negative, without decimals of unlimited length.

2.1.1 Example

Integers:

x = 1
y = 35656222554887711
z = -3255522

print(type(x))
print(type(y))
print(type(z))

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2.2 Float

Float, or "floating point number" is a number, positive or negative, containing one or more decimals.

2.2.1 Example

Floats:

x = 1.10
y = 1.0
z = -35.59

print(type(x))
print(type(y))
print(type(z))

Float can also be scientific numbers with an "e" to indicate the power of 10.

Floats:

x = 35e3
y = 12E4
z = -87.7e100

print(type(x))
print(type(y))
print(type(z))

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2.3 Complex

Complex numbers are written with a "j" as the imaginary part:

2.3.1 Example

Complex:

x = 3+5j
y = 5j
z = -5j

print(type(x))
print(type(y))
print(type(z))

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2.4 Type Conversion

You can convert from one type to another with the int(), float(), and complex() methods:

2.4.1 Example

Convert from one type to another:

x = 1    # int
y = 2.8  # float
z = 1j   # complex

#convert from int to float:
a = float(x)

#convert from float to int:
b = int(y)

#convert from int to complex:
c = complex(x)

print(a)
print(b)
print(c)

print(type(a))
print(type(b))
print(type(c))

note

You cannot convert complex numbers into another number type.

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2.5 Random Number

Python does not have a random() function to make a random number, but Python has a built-in module called random that can be used to make random numbers:

2.5.1 Example

Import the random module, and display a random number from 1 to 9:

import random

print(random.randrange(1,10))