Module 1 - Day 5

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Quick recap

Basic data types
Collections
built in functions - max, min, sum, sorted, len, range, list
methods from string - startswith, endswith , split, join
methods lists - append, insert, remove, reverse
custom functions
conditions and loops

built in modules

import random # once this import statement is executed ....there will be a variable with name random

random

<module 'random' from '/opt/tljh/user/lib/python3.10/random.py'>

len

<function len(obj, /)>

def foo():
    pass # empty statement

foo

<function __main__.foo()>

ones = [1, 1, 1, 1]

ones.index(1)

random.random() # with generate a random number between 0 and 1

0.17037947163424505

problem

Write a function generate_randoms which will gnerate a list of n random numbers (value between 0-1)

import random

def generate_randoms(n): # n is integer

for i in range(5):
    print(i)

nums = []
nums.append(0)

random.random()

0.9902054030841536

range(5)

range(0, 5)

for i in range(5):
    print(i)

for i in range(5):
    print(i, end=",") # end the print with "," instead of \n

0,1,2,3,4,

for i in range(5):
    print(i, end=" ")

0 1 2 3 4

import random

def generate_randoms(n): # n is integer
    randnums = []

    for i in range(n):
        r = random.random()
        randnums.append(r)

    return randnums

generate_randoms(3)

[0.009110195281217481, 0.5968671809207017, 0.7455438096633993]

generate_randoms(8)

[0.5552308671158126,
 0.3699835115213501,
 0.06719071835236257,
 0.8500590744050013,
 0.3948638112419627,
 0.49646221176988414,
 0.7966689902599045,
 0.9940776054647534]

import math

import os

import math as m # this is like giving alias to the module name

m.sin(0)

0.0

import pandas as pd # this is thrid party module

---------------------------------------------------------------------------
ModuleNotFoundError                       Traceback (most recent call last)
Cell In[29], line 1
----> 1 import pandas as pd # this is thrid party module

ModuleNotFoundError: No module named 'pandas'

import numpy as np

---------------------------------------------------------------------------
ModuleNotFoundError                       Traceback (most recent call last)
Cell In[30], line 1
----> 1 import numpy as np

ModuleNotFoundError: No module named 'numpy'

os module

import os

os.getcwd() # working directory of python

'/opt/arcesium-python-2024-june'

os.path # is submodule inside os module

<module 'posixpath' from '/opt/tljh/user/lib/python3.10/posixpath.py'>

# path  absolute path, relative path
# absoulte path c:\\Program Files\\Python\bin\python.exe
# relative path - relative to current working directory
os.path.isdir(path) # this will check if given path is folder or not

#os.listdir - > list files from given directory

os.listdir(os.getcwd()) # it returns names of all files and folders from

['.ipynb_checkpoints',
 'lab.qmd',
 '1-3.ipynb',
 'index.qmd',
 'about.qmd',
 '_site',
 '.gitignore',
 'styles.css',
 '1-1.ipynb',
 '.quarto',
 'syllabus.qmd',
 '1-2.ipynb',
 'schedule.qmd',
 '1-5.ipynb',
 '_quarto.yml',
 '.git',
 'README.md',
 '1-4.ipynb']

os.listdir("/home/jupyter-pipal/")

['.config',
 '.ipynb_checkpoints',
 'training',
 'final',
 '.python_history',
 '.bash_logout',
 'users.txt',
 'hello-world.ipynb',
 'startup.py',
 '.ipython',
 '.jupyterhub-token.txt',
 '.ssh',
 '.bashrc',
 '.gitconfig',
 'sync.py',
 'setup.ipynb',
 '.cache',
 '.wget-hsts',
 '.viminfo',
 '.jupyter',
 '.lesshst',
 'setup_magic.sh',
 '.profile',
 '.bash_history',
 '.local']

os.listdir("test") # this is relative path with respect current working directory

['.ipynb_checkpoints', 'test.txt']

os.getcwd()

'/opt/arcesium-python-2024-june'

os.listdir("/opt/arcesium-python-2024-june/test") # this is absolute path

['.ipynb_checkpoints', 'test.txt']

whenever you construct path using python program make sure to use os.path module

folders = ["Program Files", "Python"]

os.path.join("Program Files", "Python") # on windows it take \\ and on linux/unix/mac it will take /

'Program Files/Python'

import time

time.sleep(2) # sleep for two seconds

def tick(n):
    for i in range(n):
        time.sleep(1)
        print("tick-", i)

    print("BOOOM....")

tick(5)

tick- 0
tick- 1
tick- 2
tick- 3
tick- 4
BOOOM....

[1, 1, 2, 4, 5, 6]
["_site", "test", "_quarto.yml", "1-1.ipynb"....]

problem

Write a function find_notebooks from current working directory notebook is a file with extension .ipynb

hints: you will have go over all the files from current working directory os.listdir()

find_notebooks()
["1-1.ipynb", "1-2.ipynb", "1-3.ipynb", "1-4.ipynb"]

import os

def find_notebooks():
    files = os.listdir()  
    notebooks = []
    for file in files:
        if file.endswith(".ipynb"):
            notebooks.append(file)
    return notebooks

find_notebooks()

['1-3.ipynb', '1-1.ipynb', '1-2.ipynb', '1-5.ipynb', '1-4.ipynb']

if we want to modify to find notebooks from any directory

import os

def find_notebooks(folderpath):
    files = os.listdir(folderpath) 
    notebooks = []
    for file in files:
        if file.endswith(".ipynb"):
            notebooks.append(file)
    return notebooks

find_notebooks()

---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
Cell In[57], line 1
----> 1 find_notebooks()

TypeError: find_notebooks() missing 1 required positional argument: 'folderpath'

find_notebooks(os.getcwd())

['1-3.ipynb', '1-1.ipynb', '1-2.ipynb', '1-5.ipynb', '1-4.ipynb']

import os

def find_notebooks(folderpath=None):
    if folderpath is None:
        folderpath = os.getcwd()
        
    files = os.listdir(folderpath) 
    notebooks = []
    for file in files:
        if file.endswith(".ipynb"):
            notebooks.append(file)
    return notebooks

def find_notebooks(folderpath=os.getcwd()): # default value
        
    files = os.listdir(folderpath) 
    notebooks = []
    for file in files:
        if file.endswith(".ipynb"):
            notebooks.append(file)
    return notebooks

find_notebooks()

['1-3.ipynb', '1-1.ipynb', '1-2.ipynb', '1-5.ipynb', '1-4.ipynb']

find_notebooks("/opt/arcesium-python-2024-june/")

['1-3.ipynb', '1-1.ipynb', '1-2.ipynb', '1-5.ipynb', '1-4.ipynb']

Writing your own modules

Write a text file with extension .py in your favorite text editor. keep that file in current working directory

import hello

hello.say_hello("vikrant")

Hello vikrant

hello.greeting("vikrant")

Welcome vikrant

hello.greeting("vikrant")

Namaskar vikrant

hello.greeting("vikrant")

Welcome vikrant

hello.greeting("vikrant")

Welcome vikrant

hello.greeting("vikrant")

How do you do? vikrant

%%file hello1.py
import random 

def say_hello(name):
    print("Hello", name)


def greeting(name):
    greetings = ["Namaskar", "Welcome", "How do you do?", "Wannakam"]
    gr = random.choice(greetings)
    print(gr, name)

Writing hello1.py

import hello1 # you give only filename without extension..don't give .py

hello1.greeting("Arcesium")

Welcome Arcesium

%%file test.txt
some test text 
for testing out %%file

Writing test.txt

%%file test.py

def foo():
    pass

Overwriting test.py

import test # once imported python will never look at the changed file

%%file test.py

def foobar():
    pass

Overwriting test.py

import test

test.foo()

---------------------------------------------------------------------------
AttributeError                            Traceback (most recent call last)
Cell In[91], line 1
----> 1 test.foo()

AttributeError: module 'test' has no attribute 'foo'

%%file testing.py

def foo():
    print("foo")

Writing testing.py

import testing

testing.foo()

foo

%%file testing.py

def foobar():
    print("foobar")

Overwriting testing.py

import testing # import happens only once

testing.foo()

foo

testing.foobar()

---------------------------------------------------------------------------
AttributeError                            Traceback (most recent call last)
Cell In[106], line 1
----> 1 testing.foobar()

AttributeError: module 'testing' has no attribute 'foobar'

Writing python scripts/programs

%%file args.py
import sys

sys.argv # this is a list of strings
print(sys.argv)

Writing args.py

%%file add.py
import sys

thisfilename = sys.argv[0]
a = int(sys.argv[1])
b = int(sys.argv[2])
s = a + b # sum is computed 
print(s)

Writing add.py

!python add.py 42 50

!python add.py 56 57

%%file welcome.py
import sys

name = sys.argv[1]
print("Welcome", name)

Writing welcome.py

%%file welcome.py
import sys

def welcome(name):
    print("Welcome", name)

name = sys.argv[1]
welcome(name)

!python welcome.py vikrant

Welcome vikrant

You will have to call the program with python from command line
all the inputs to your program goes from command line arguments
all the command line arguments are text by default
first argument is always your program name

problem

Write a program mysum.py to sum multiple integers from commnad line

from jupyter prompt it will run like this

!python mysum.py 1 2 3 4 5 6 7 8 9 10
55

import sys

sys.argv # these are the arguments with which this jupuyter program started

['/opt/tljh/user/lib/python3.10/site-packages/ipykernel_launcher.py',
 '-f',
 '/home/jupyter-pipal/.local/share/jupyter/runtime/kernel-b0c672a5-6c8d-4cdb-ba1d-3e63a06186fe.json']

nums = list(range(10))

nums

[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]

nums[1:] # drop first item

[1, 2, 3, 4, 5, 6, 7, 8, 9]

# sys.argv[1:] # these will be number given by user from command line for our mysum.py program

%%file mysum.py
import sys # modules are imported at top

def to_ints(text_args):
    nums = []
    for t in text_args:
        nums.append(int(t))

    return nums
    
text_nums = sys.argv[1:]
nums = to_ints(text_nums)
print(sum(nums))

Writing mysum.py

!python mysum.py 1 2 3 4 5 6 7 8 9 10

%load_problem square

Problem: Square

Write a function square to compute the square of a number.

>>> square(4)
16

You can verify your solution using:

%verify_problem square

# your code here

def square(x):
    return x*x

square(5)

%verify_problem square

Found 2 checks
✓ verify square(2)
✓ verify square(4)
🎉 Congratulations! You have successfully solved problem square!!