Chapter 2: Functions & Modularization (continued)¶
The Standard Library¶
math 
Module
In [1]:
import math
In [2]:
math
Out[2]:
<module 'math' from '/usr/lib64/python3.12/lib-dynload/math.cpython-312-x86_64-linux-gnu.so'>
In [3]:
id(math)
Out[3]:
140177537558144
In [4]:
type(math)
Out[4]:
module
In [6]:
math.pi
Out[6]:
3.141592653589793
In [7]:
math.e
Out[7]:
2.718281828459045
In [8]:
math.sqrt
Out[8]:
<function math.sqrt(x, /)>
In [9]:
help(math.sqrt)
Help on built-in function sqrt in module math:
sqrt(x, /)
Return the square root of x.
In [10]:
math.sqrt(2)
Out[10]:
1.4142135623730951
In [11]:
math.sqrt(2 ** 2)
Out[11]:
2.0
In [12]:
math.sqrt(sum([99, 100, 101]) / 3)
Out[12]:
10.0
random Module
In [15]:
import random
In [16]:
random
Out[16]:
<module 'random' from '/usr/lib64/python3.12/random.py'>
In [18]:
random.random
Out[18]:
<function Random.random()>
In [19]:
help(random.random)
Help on built-in function random:
random() method of random.Random instance
random() -> x in the interval [0, 1).
In [20]:
random.random()
Out[20]:
0.782609162553633
In [21]:
random.choice
Out[21]:
<bound method Random.choice of <random.Random object at 0x561db35d9a60>>
In [22]:
help(random.choice)
Help on method choice in module random:
choice(seq) method of random.Random instance
Choose a random element from a non-empty sequence.
In [23]:
numbers = [7, 11, 8, 5, 3, 12, 2, 6, 9, 10, 1, 4]
In [24]:
random.choice(numbers)
Out[24]:
4
In [25]:
random.seed(42)
In [26]:
random.random()
Out[26]:
0.6394267984578837
In [27]:
random.seed(42)
In [28]:
random.random()
Out[28]:
0.6394267984578837
Third-party Packages¶
In [29]:
!pip install numpy
Requirement already satisfied: numpy in /home/alexander/Repositories/intro-to-python/.venv/lib64/python3.12/site-packages (1.26.4)
In [30]:
import numpy as np
In [31]:
np
Out[31]:
<module 'numpy' from '/home/alexander/Repositories/intro-to-python/.venv/lib64/python3.12/site-packages/numpy/__init__.py'>
In [32]:
vec = np.array(numbers)
In [33]:
vec
Out[33]:
array([ 7, 11, 8, 5, 3, 12, 2, 6, 9, 10, 1, 4])
In [34]:
type(vec)
Out[34]:
numpy.ndarray
In [35]:
2 * vec
Out[35]:
array([14, 22, 16, 10, 6, 24, 4, 12, 18, 20, 2, 8])
In [36]:
2 * numbers # surprise, surprise
Out[36]:
[7, 11, 8, 5, 3, 12, 2, 6, 9, 10, 1, 4, 7, 11, 8, 5, 3, 12, 2, 6, 9, 10, 1, 4]
In [37]:
sum(vec)
Out[37]:
78
In [38]:
random.choice(vec)
Out[38]:
7
Local Modules and Packages¶
In [39]:
!pwd
/home/alexander/Repositories/intro-to-python/02_functions
In [40]:
import sample_module as mod
In [41]:
mod
Out[41]:
<module 'sample_module' from '/home/alexander/Repositories/intro-to-python/02_functions/sample_module.py'>
In [43]:
mod.average_evens
Out[43]:
<function sample_module.average_evens(numbers, *, scalar=1)>
In [44]:
help(mod.average_evens)
Help on function average_evens in module sample_module:
average_evens(numbers, *, scalar=1)
Calculate the average of all even numbers in a list.
Args:
numbers (list of int's/float's): numbers to be averaged;
if non-whole numbers are provided, they are rounded
scalar (float, optional): multiplies the average; defaults to 1
Returns:
scaled_average (float)
In [45]:
mod.average_evens(numbers)
Out[45]:
7.0
In [46]:
mod.average_evens(numbers, scalar=2)
Out[46]:
14.0