. Python Functions

# Defining a function  
def my_function():
    print("Hello from a function")
# Calling a function 
my_function()

# adding argument 
def my_func(a):
    print(a)
my_func('hello')

# multiple arguments  
def my_func(a,b):
    print(a+b)
my_func(1,2)

# return statement in a function 
def my_func(a,b):
    return a+b
var1=1
var2=2
total=my_func(var1,var2)
print(total)

# what if the number of arguemts are not fixed
def my_func(*args):
    return sum(args)
print(my_func(1,2,3))
print(my_func(1,2,3,4))
print(my_func(1,2,3,5,6))

# keyword argument - you can also send named arguments to the function
def my_func(val1,val2,val3):
    print(f"val1 is {val1}")
    print(f"val2 is {val2}")
    print(f"val3 is {val3}")
my_func(val1=1,val3=3,val2=2) # notice that i am passing val3 first and val2 at the last because this is a keyword argument

# Artibitary keyword argument
def myfunc(**keyword):
    print("my name is ",keyword['name'])
    print("my occupation is ",keyword['occ'])
myfunc(name='pranjal',occ='DS')

# Default value of a parameter
def myfunc(a,b=2):
    return a/b
myfunc(2,1)

# Passing sequence data types in function 
def myfunc(l):
    for i in l:
        print(i)
lst=[1,2,3,2,1]
myfunc(lst)    

# recursive functions - finding factoricla
def factorical(n):
    if n==0:
        return 1
    else:
        return n*factorical(n-1)
factorical(5)

add = lambda x,y:x+y
add(3,4)

# It is used to create another function
def myfunc(n):
    return lambda x:x*n
doubler=myfunc(2)
tripler=myfunc(3)
print(doubler(5))
print(tripler(5))

# write a function to check if a number is a prime number or not

# write a function to count the number of vowels in a sentence 

# write a function that returns the sum of a list

import os 

# get current working directory 
os.getcwd()

# make a directory
os.mkdir("directory_path")

# join file and folder names 
folder_path=r"C:\Users\pranjal.p.bhatt.INTKYV\Documents\python projects\Training"
file_name="Test Data.csv"
os.path.join(folder_path,file_name)

# list of all files in a folder
os.listdir(folder_path)

# remove file or directory 
# os.remove(file_full_path)
# os.rmdir(folder_path)

# check if a path exist or not
os.path.exists("file_path")

import datetime as dt

# get current time 
print(dt.datetime.now())
print(type(dt.datetime.now()))

# converting current time to string 
print(str(dt.datetime.now()))

# extract only current date 
print(dt.datetime.now().date())

# convert string to datetime type object 
time_str='2020-01-31 00:21:30'
datetime_object=dt.datetime.strptime(time_str,'%Y-%m-%d %H:%M:%S')
datetime_object

# extracting year ,month etc from datetime types object 
print(datetime_object.year)
print(datetime_object.month)
print(datetime_object.day)
print(datetime_object.hour)

# convert datetime to string format 
time_str='2020-01-31 00:21:30'
datetime_object=dt.datetime.strptime(time_str,'%Y-%m-%d %H:%M:%S')
str_object=dt.datetime.strftime(datetime_object,'%m-%d-%Y %H:%M:%S')

str_object

# difference between 2 date object 
start=dt.datetime.now()
[x**2 for x in range(10000000)]
delta=dt.datetime.now()-start
delta.total_seconds()

import random

# generate random number between a range 
random.randint(1,100)

# generate random decimal number 
random.uniform(a=100,b=1000) # random decimal number between 100 and 1000

# get random value from a list 
sample_list=[1,2,3,4,5,6,6,7,8]
print(random.choice(sample_list))