9  Module 1 - Day 4

Topics

For today’s practice make use of notebook module1-day4.ipynb created in your enviroment. Shut down kernel for all previous notebooks by right cliking on notbeook on left hand side file browser.

9.1 Quick recap of for loop

words = "For today’s practice make use of notebook module1-day4.ipynb created in your enviroment.".split()
words
['For',
 'today’s',
 'practice',
 'make',
 'use',
 'of',
 'notebook',
 'module1-day4.ipynb',
 'created',
 'in',
 'your',
 'enviroment.']
for w in words:
    print("X" + w)
XFor
Xtoday’s
Xpractice
Xmake
Xuse
Xof
Xnotebook
Xmodule1-day4.ipynb
Xcreated
Xin
Xyour
Xenviroment.
for x in [1, 2, 3, 4, 5]:
    print(x*x)
1
4
9
16
25
stocks = [{"name":"AAPLE", "value":245},
         {"name":"AT&T", "value":300},
         {"name": "TESLA", "value": 200}]
values = []
for s in stocks:
    values.append(s['value'])
values
[245, 300, 200]
def extract_values(stockslist):
    values = []
    for s in stocks:
        values.append(s['value'])
    return values
extract_values(stocks)
[245, 300, 200]
def extract_items(stocks, itemname):
    values = []
    for s in stocks:
        values.append(s[itemname])
    return values
extract_items(stocks, "name")
['AAPLE', 'AT&T', 'TESLA']
extract_items(stocks, "value")
[245, 300, 200]
def mysum(numbers):
    s = 0
    for i in numbers:
        s = s + i
    return s
mysum([245, 300, 200])
745
  • Write a function product which finds product of all elements from a list.
    >>> product([3, 2, 4])
    24
  • Write a function factorial to find factorial of a number. Hint : Use function range(1,n) to generate numbers from 1 to n. if you put for loop on this range(1,n) it will give numbers 1 to n
  >>> factorial(5)
  120
  • Write a function findlens which finds lengths of every word from a given list of words.
    >>> findlens(["one", "two", "three"])
    [3, 3, 5]
def product(numbers):
    p = 1
    for n in numbers:
        p = p * n
    return p
def factorial(n):
    return product(range(1, n+1))
factorial(5)
120
for i in range(1, 5):
    print(i)
1
2
3
4
for i in range(10):
    print(i)
0
1
2
3
4
5
6
7
8
9
for i in range(1, 11):
    print(i)
1
2
3
4
5
6
7
8
9
10
def foo(x): # this is definition
    return x*x
foo(5)
25
factorial(5)
120
factorial(5)
120
def findlens(words):
    lenghts = []
    for w in words:
        lenghts.append(len(w))
    return lenghts
findlens(words)
[3, 7, 8, 4, 3, 2, 8, 18, 7, 2, 4, 11]
words
['For',
 'today’s',
 'practice',
 'make',
 'use',
 'of',
 'notebook',
 'module1-day4.ipynb',
 'created',
 'in',
 'your',
 'enviroment.']

9.2 conditons

  1. if some conditon is satisfied do something….
if cond:
    do something
  1. only one the if/elif/else conditions will be executed
if cond1:
    do 1
elif cond2:
    do 2
elif cond3:
    do 3
else:
    do otherwise
  1. only one of the if/else condition will be executed
if cond:
    do something
else:
    do rest
text = "this is test"
text.startswith("this")
True
x = 6
y = 10
x > y
False
x < y
True
x == y
False
x != y # not equal
True
x <= y
True
x >= y
False
(x > y) and (text.startswith("t"))
False
x > y and text.startswith("t")
False
"this" in text
True
words
['For',
 'today’s',
 'practice',
 'make',
 'use',
 'of',
 'notebook',
 'module1-day4.ipynb',
 'created',
 'in',
 'your',
 'enviroment.']
"For" in words
True
"for" in words # case sensitive
False
def mymax(x, y):
    if x> y:
        return x
    else:
        return y
mymax(45, 56)
56
if x < y:
    print("Y")
else:
    print("X")
Y

problems

  • Write a function find_words_of_len to find words of given length from given list.
    >>> find_words_of_len(words, 3)
    ['one', 'two', 'six']
ones = [1, 1, 1, 1]
x = ones.append(1)
print(x)
None
y
10
print(x)
None
x
print(x)
None
def foo():
    return None
foo()
primes[] # this means primes already exists and I am about to access items from it
primes = []  # i am defining a new variable 
def find_words_of_len(words, length):
    desired_words = []
    for w in words:
        if len(w) == length:
            #return w  this return here will stop the for loop the moment first word is found!
            desired_words.append(w) # 
            #return desired_words # this will return a list with first word in a list  
        #return desired_words desired_words # this will return a list with first word in a list
    return desired_words # look at the indentation!
find_words_of_len(words, 4)
['make', 'your']
words
['For',
 'today’s',
 'practice',
 'make',
 'use',
 'of',
 'notebook',
 'module1-day4.ipynb',
 'created',
 'in',
 'your',
 'enviroment.']
def find_words_of_len(words,x):
    p=[]
    for w in words:
        if len(w)==x:
            p.append(w)
    return p
find_words_of_len(words, 4)
['make', 'your']
sqrs_even = []
for i in range(20):
    if i%2==0:
        sqrs_even.append(i)
sqrs_even
[0, 2, 4, 6, 8, 10, 12, 14, 16, 18]
def squares_even(numbers):
    sqrs_even = []
    for i in numbers:
        if i%2==0:
            sqrs_even.append(i)
    return sqrs_even
squares_even(range(20))
[0, 2, 4, 6, 8, 10, 12, 14, 16, 18]

Write a function unique which will remove duplicates from a list.

    >>> unique([1, 1, 2, 3, 1, 2, 3, 2, 4])
    [1, 2, 3, 4]
def unique(items):
    unique_box = []
    for item in items:
        if item not in unique_box:
            unique_box.append(item)
    return unique_box
unique([1, 2, 3, 1, 1, 12, 2, 3, 4, 7, 4, 7, 7])
[1, 2, 3, 12, 4, 7]
def unique(items):
    unique_box = []
    for item in items:
        if item in unique_box:
            continue # continue statement allows to go back to for loop next iteration
        else:
            unique_box.append(item)
    return unique_box

9.3 modules

math
---------------------------------------------------------------------------
NameError                                 Traceback (most recent call last)
Cell In[82], line 1
----> 1 math

NameError: name 'math' is not defined
import math
math
<module 'math' from '/opt/tljh/user/lib/python3.12/lib-dynload/math.cpython-312-x86_64-linux-gnu.so'>
math.sin(math.pi)
1.2246467991473532e-16
math.exp(10)
22026.465794806718
import random
random.random() # generate a random number betweeb 0 to 1
0.18358511958951218
random.choice(words) # this choosed a random item from a list
'of'
random.choice(words)
'module1-day4.ipynb'
words
['For',
 'today’s',
 'practice',
 'make',
 'use',
 'of',
 'notebook',
 'module1-day4.ipynb',
 'created',
 'in',
 'your',
 'enviroment.']
random.choice([1, 34,4 , 6, 2, 6])
6
import math as m # you can give alias to the imported module
m.pi
3.141592653589793
math.pi
3.141592653589793
import os
os.listdir() # this will give list of all files in current working directory
['index.qmd',
 '.ipynb_checkpoints',
 'module1-day4.ipynb',
 'module1-day1.ipynb',
 'module1-day3.ipynb',
 'module1-day2.ipynb']
os.getcwd()
'/opt/arcesium-finop-25/website/live-notes'
"/home/jupyter-anmol/"
os.listdir("/home/jupyter-vikrant/training/") # if you pass a folder name here .. 
# it will give files and folders in that folder
['README.md',
 'pipalhub-magic',
 'files',
 'setup-anand.md',
 'etc',
 'users.txt',
 'vendor',
 'problems',
 'quarto-1.8.26-linux-amd64.deb',
 'final',
 'website',
 'requirements.txt',
 '.git',
 '.gitmodules',
 'scripts',
 '.gitignore',
 'instructions.md']
files = os.listdir(os.getcwd())
for f in files:
    print(f, os.path.isfile(f))
index.qmd True
.ipynb_checkpoints False
module1-day4.ipynb True
module1-day1.ipynb True
module1-day3.ipynb True
module1-day2.ipynb True
for f in files:
    print(f, os.path.isfile(f))
index.qmd True
.ipynb_checkpoints False
module1-day4.ipynb True
module1-day1.ipynb True
module1-day3.ipynb True
module1-day2.ipynb True
os.getcwd()
'/opt/arcesium-finop-25/website/live-notes'
files = os.listdir('/opt/arcesium-finop-25/website/live-notes')
for f in files:
    if os.path.isfile(f):
        print("f", f)
    else:
        print("d", f)
f index.qmd
d test
d test1
d .ipynb_checkpoints
f module1-day4.ipynb
f module1-day1.ipynb
f module1-day3.ipynb
f module1-day2.ipynb
os.path.getsize("module1-day1.ipynb") # size in bytes
75255
os.listdir("c:\\")
---------------------------------------------------------------------------
FileNotFoundError                         Traceback (most recent call last)
Cell In[114], line 1
----> 1 os.listdir("c:\\")

FileNotFoundError: [Errno 2] No such file or directory: 'c:\\'
os.path.sep
'/'
os.path.join("c:", "Program Files")
'c:/Program Files'
os.getcwd() # path to current working directory
'/opt/arcesium-finop-25/website/live-notes'
os.listdir() # list files 
['index.qmd',
 'txt1.txt',
 'test',
 'test1',
 '.ipynb_checkpoints',
 'module1-day4.ipynb',
 'module1-day1.ipynb',
 'module1-day3.ipynb',
 'module1-day2.ipynb',
 'hello.txt']
os.path.getsize("hello.txt")
0
os.path.getsize("untitled.txt")
---------------------------------------------------------------------------
FileNotFoundError                         Traceback (most recent call last)
Cell In[121], line 1
----> 1 os.path.getsize("untitled.txt")

File <frozen genericpath>:62, in getsize(filename)

FileNotFoundError: [Errno 2] No such file or directory: 'untitled.txt'
os.path.getsize(os.path.join("test","untitled.txt"))
86
relative_path = os.path.join("test","untitled.txt")
relative_path
'test/untitled.txt'
os.path.abspath(relative_path)
'/opt/arcesium-finop-25/website/live-notes/test/untitled.txt'

problem - Write a function findpyfiles from given folder

  findpyfiles("test")
  ['untitled.py', "untitled1.py", "untitled2.py", "untitled3.py", "untitled4.py"]
  • How will you find biggest file from given list of files? hint: remember max with key argument?
  • Write a function greeting which greets randomly in variaus ways::
    >>> greeting("Vikrant")
    "Hello Vikrant"
    >>> greeting("Vikrant")
    "Namaste Vikrant"
    >>> greeting("Vikrant")
    "Good day Vikrant"
    >>> greeting("Vikrant")
    "Guten morgen Vikrant"
foldername = "test"
hello
---------------------------------------------------------------------------
NameError                                 Traceback (most recent call last)
Cell In[128], line 1
----> 1 hello

NameError: name 'hello' is not defined
"hello"
'hello'
def is_pyfile(filename):
    return filename.endswith(".py")
is_pyfile("hello.py")
True
is_pyfile("hello.txt")
False
os.path.isfile("hello.txt")
True
os.path.isfile("untitled.txt")
False
os.path.isfile(os.path.join("test", "untitled.txt"))
True
os.path.join("test", "untitled.txt")
'test/untitled.txt'
os.listdir("test")
['untitled1.py',
 '.ipynb_checkpoints',
 'untitled2.txt',
 'untitled3.txt',
 'untitled2.py',
 'untitled3.py',
 'untitled.py',
 'untitled1.txt',
 'untitled4.py',
 'untitled.txt']
os.listdir("test")
['untitled1.py',
 '.ipynb_checkpoints',
 'untitled2.txt',
 'untitled3.txt',
 'untitled2.py',
 'untitled3.py',
 'untitled.py',
 'untitled1.txt',
 'untitled4.py',
 'untitled.txt']
import random

def greetings(name):
    greets = ["Hello", "Namaskar", "Good day", "Have a nice day"]
    greeting_for_now = random.choice(greets)
    print(greeting_for_now, name)
greetings("vikrant")
Namaskar vikrant
def findpyfiles(folder):
    files = os.listdir(folder)
    pyfiles = []
    for f in files:
        if f.endswith(".py"):
            pyfiles.append(f)
    return pyfiles
findpyfiles("test")
['untitled1.py', 'untitled2.py', 'untitled3.py', 'untitled.py', 'untitled4.py']
findpyfiles(os.getcwd())
['untitled.py']
words
['For',
 'today’s',
 'practice',
 'make',
 'use',
 'of',
 'notebook',
 'module1-day4.ipynb',
 'created',
 'in',
 'your',
 'enviroment.']
max(words, key=len)
'module1-day4.ipynb'
os.path.getsize("module1-day1.ipynb")
75255
files = os.listdir(os.getcwd())
files
['index.qmd',
 'txt1.txt',
 'test',
 'test1',
 '.ipynb_checkpoints',
 'module1-day4.ipynb',
 'module1-day1.ipynb',
 'module1-day3.ipynb',
 'module1-day2.ipynb',
 'hello.txt',
 'untitled.py']
max(files, key=os.path.getsize)
'module1-day2.ipynb'
for f in files:
    print(f, os.path.getsize(f))
index.qmd 185
txt1.txt 0
test 4096
test1 4096
.ipynb_checkpoints 4096
module1-day4.ipynb 55041
module1-day1.ipynb 75255
module1-day3.ipynb 63223
module1-day2.ipynb 79656
hello.txt 0
untitled.py 0
def find_biggest_file(folder):
    files = os.listdir(folder)
    filespaths = []
    for f in files:
        path = os.path.join(folder, f)
        filespaths.append(path)
    return max(filespaths, key=os.path.getsize)
        
os.path.getsize("untitled.txt")
---------------------------------------------------------------------------
FileNotFoundError                         Traceback (most recent call last)
Cell In[155], line 1
----> 1 os.path.getsize("untitled.txt")

File <frozen genericpath>:62, in getsize(filename)

FileNotFoundError: [Errno 2] No such file or directory: 'untitled.txt'
find_biggest_file("test")
'test/.ipynb_checkpoints'
find_biggest_file("test")
'test/untitled.txt'
os.path.getsize("test") # it can estimate only file size not folder size
4096
import datetime
date = datetime.datetime(2025, 11, 20)
date
datetime.datetime(2025, 11, 20, 0, 0)
date1 = datetime.datetime(2025, 11, 25)
date1 > date
True
date2 = datetime.datetime(2025, 11, 15)
date2
datetime.datetime(2025, 11, 15, 0, 0)
date
datetime.datetime(2025, 11, 20, 0, 0)
date2
datetime.datetime(2025, 11, 15, 0, 0)
date
datetime.datetime(2025, 11, 20, 0, 0)
date2 < date
True
threedays = datetime.timedelta(days=3)
date + threedays
datetime.datetime(2025, 11, 23, 0, 0)

problem - Write a function trange which generates n dates from start date. if start is not given , today is taken as start date.

    >>> trange(5, datetime.datetime(2019, 1, 1))
    [datetime.datetime(2019, 1, 1, 0, 0),
     datetime.datetime(2019, 1, 2, 0, 0),
     datetime.datetime(2019, 1, 3, 0, 0),
     datetime.datetime(2019, 1, 4, 0, 0),
     datetime.datetime(2019, 1, 5, 0, 0)]
datetime.datetime.now() # this will give current date time
datetime.datetime(2025, 12, 15, 7, 56, 57, 352400)
def cylinder_volume(radius, height):
    return math.pi*radius**2*height


    
    
cylinder_volume(1.0, 5)
15.707963267948966
cylinder_volume(5, 1) # by mistake I passed arguments in wrong order
78.53981633974483
cylinder_volume(radius=1, height=5) # named arguments
15.707963267948966
cylinder_volume(height=5, radius=1)
15.707963267948966
cylinder_volume(1, height=5)
15.707963267948966
cylinder_volume(radius=1, 5)
  Cell In[209], line 1
    cylinder_volume(radius=1, 5)
                               ^
SyntaxError: positional argument follows keyword argument

def cylinder_volume(radius, height=1.0): # default argument value
    return math.pi*radius**2*height
cylinder_volume(1) # this will take radius as 1 and helght 1 
3.141592653589793
cylinder_volume(1, 5)
15.707963267948966
cylinder_volume(radius=1, height=5) 
15.707963267948966
def trange(n, startdate=None):
    if startdate is None:
        startdate = datetime.datetime.now()
    dates = []
    for i in range(n):
        delta = datetime.timedelta(days=i)
        dates.append(startdate + delta)
    return dates
trange(5)
[datetime.datetime(2025, 12, 15, 8, 6, 53, 208864),
 datetime.datetime(2025, 12, 16, 8, 6, 53, 208864),
 datetime.datetime(2025, 12, 17, 8, 6, 53, 208864),
 datetime.datetime(2025, 12, 18, 8, 6, 53, 208864),
 datetime.datetime(2025, 12, 19, 8, 6, 53, 208864)]
trange(5, date)
[datetime.datetime(2025, 11, 20, 0, 0),
 datetime.datetime(2025, 11, 21, 0, 0),
 datetime.datetime(2025, 11, 22, 0, 0),
 datetime.datetime(2025, 11, 23, 0, 0),
 datetime.datetime(2025, 11, 24, 0, 0)]