• general-purpose
• interactive
• object-oriented
• high-level
• Open Source (GNU GPL)
• interpretor
• programming language
• created by Guido van Rossum
• www.python.org

Data Input
name = input("Enter Your Name ")
print ("Your name is : ")
print (name)

# \n within quote marks forces a new line 
age = input("Enter Your Age\n")
print ("Your age is:")
print (age)

#example a=b+c
number1 = input()  # enter 1
number2=  input()  # enter 2
number3=number1+ number2
print (number3) # check the output
# output is 12 why? 
# try entering decimal numbers 1.5 and 2.7
# output is 1.52.7 why? 

number1 = input()  # enter 1
n1=int(number1)
number2 = input()  # enter 2
n2=int(number2)
n3= n1+ n2
print (n3) # check the output 
# output is 3 explain 

#program to calculate average of 2 numbers
total = 0.0
number1=float(input("Enter number 1: "))
total = total + number1
number2=float(input("Enter tnumber 2: "))
total = total + number2
average = total / 2
print ("Average : " + str(average))

#to read all the input at a time
#sys.stdin opens data like a  file
# import sys module first
import sys  
data = sys.stdin.readlines()
print (data)

#space delimitted numbers in line. 
arr = map(int, input().split())
print(arr[0])
print(arr)

#examples
name="Ruvini"
age=18
height=5.6

Reassigning Variables
name="Sindi" # name is set to "Sindi"
age=19   # age is set to 19
height=5.7   # height is now set 5.7

#!/usr/bin/python

str = 'Hello Python!'

print str       # Prints complete string
print str + "T" # Prints concatenated string
print str * 2   # Prints string two times
print str[0]    # Prints first character
print str[2:5]  # Prints from 3rd to 5th
print str[2:]   # Prints from 3rd character

#The output will be
Hello python!
Hello python!T
Hello python!Hello python!
H
llo
llo python!

int(x ) - Converts x to an integer. 
long(x) Converts x to a long integer. 
float(x) - Converts x to a floating-point number.
str(x) - Converts object x to a string.

chr(x) - Converts an integer to a character.
ord(x)-  Converts a single character to its integer value.

hex(x) -Converts an integer to a hexadecimal string.
oct(x) - Converts an integer to an octal string.
unichr(x) - Converts an integer to a Unicode character.

eval(str) - Evaluates a string and returns an object.
tuple(s) - Converts s to a tuple.
list(s) - Converts s to a list.
dict(d) - Creates a dictionary from (key,value) tuples.
set(s) -Converts s to a set.

#array example
myList=[1,2,3,4,5,6]
print(myList[0], myList[5])

myList[0]=100
print(myList[0])

myList[1]="Yasas"
print(myList[1])

#!/usr/bin/python

list1 = [1,23, 'Ruwini',7]

print list1      # Prints complete list
print list1[0]   # Prints first element
print list1[1:3] # Prints from 2nd till 3rd 
print list[2:]   # Prints from 3rd element

#what would be the output?

tuple1 = (123, 'Niki', "Sugi",9)

print tuple1       # Prints complete list
print tuple1[0]    # Prints first element 
print tuple1[1:3]  # Prints from 2nd till 3rd 
print tuple1[2:]   # Printsfrom 3rd element

#What will be the output ?

dict1 = {}
dict1['one'] = "One"
dict1[2]     = "Two"

print dict1['one']       # Prints value for 'one' key
print dict1[2]           # Prints value for 2 key
print dict1          # Prints complete dictionary
print dict1.keys()   # Prints all the keys
print dict1.values() # Prints all the values

#The output will be
One
Two
{2: 'Two', 'one': 'One'}
[2, 'one']
['Two', 'One']

#Arithmetic Operators
a=2+3  	 # Add
b=9-2    # Subtraction
c= 108 * 0.5 # multiplication
c= 6/2   # Division
eight = 2 ** 3 # Exponentiation

x=10
y=2
#How do you get 100 using x,y
z=x**y # Exponentiation

# Modulo returns the remainder from a division
print (1% 3) # yields 1
print (2% 3) # yields 2
print (3% 3) # yields 0
print (4% 3) # yields 1

# Floor Division 
print (9//2) # yields 4 
print (-11//3)  #yields -4

> bigger than
< smaller than
== equal value
<= smaller OR equal
>= bigger OR equal
!= not equal

# run following code

print (7 > 10) # false
print (4 < 16) # true
print (4 == 4) # true
print (4 <= 4) # true
print (4 >= 4) # true
print (4 != 4) #  false

# isPositive true or false?
number = 10
isPositive = (number > 0)

c = a + b  # assigns value of a + b into c

c += a  # equivalent to c = c + a

c -= a  # equivalent to c = c - a

c *= a  # equivalent to c = c * a
#example - check output
c=1
c+=3
print(c) #output 4
c*=3
print(c)

#What will be output ?
x = 4
y = x + 1
x = 2
print (x, y)

#What will be output ?
a, b = 2, 3
print (a, b)
b, c = a, b + 1
print (a, b,c)

#produces True only if x is greater than 0 and at the same time, x is less than 10.
x > 0 and x < 10 

#produces True if any of the conditions is True
# true if the number n is divisible by 2 or it is divisible by 3. 
n % 2 == 0 or n % 3 ==0

#What if n is divisible by both 2 and by 3 ? 

#not operator negates a Boolean value
#true if x is less than or equal to y
not (x > y) is True if (x > y) # is False 

x=2
y={1,2,3,4,5}
Z=x in y # Z is  true if x is a member of y.
R= x not in y # Z is false if x is not a member of y.

#Identity operators 
Z=x is y # Z is true  if id(x) equals id(y).
R= x is not y # , Z is true  if id(x) not equals id(y).

x = 17 / 2 * 3 + 2
print (x)
 
# / and * share equal precedence 
# They are higher than the + and - operators.  
#  division and multiplication done before the addition, 
# Evaluate x, y, z and p

x = 2 + 17 / 2 * 3
y = 19 % 4 + 15 / 2  * 3
z = (15 + 6) - 10 * 4
p = 17 / 2 % 2 * 3**3

if it is raining , I need an umbrella

if it is a holiday, I can sleep more , else I have to get up early.

if I have money , I can buy a camera, else if i have a photographer friend, I can borrow a camera, else I will not do photography.

#if statement
#change a and b values 
a=1
b=2
c=a+b

if (c==3) :
    print ('total is 3')
else:
    print ('total is not 3')

# indent (spacing out) your code.
# every code block indented with tab or 4 spaces

# multiple if statements
marks = input("Enter marks: ")
marks = int(marks)
if marks >= 75:
    grade = 'A'
else:
    if marks >= 60:
        grade = 'B'
    else:
        grade = 'C'

print ("Grade is: " + grade)

# Nested if example 
marks = input("Enter marks: ")
marks = int(marks)
if marks >= 80:
    grade = 'A'
else:
    if marks >= 70:
        grade = 'B'
    else:
        if marks >= 55:
            grade = 'C'
        else:
            if marks >= 50:
                grade = 'Pass'
            else:
                 grade = 'Fail'
				 
print ("\n\nGrade is: " + grade)

# using elif  
marks = input("Enter marks: ")
marks = int(marks)
if marks >= 75 :
    grade = 'A'
elif marks >= 60:
    grade = 'B'
elif marks >= 50 :
    grade = 'C'
elif marks >= 40 :
    grade = 'S'
else:
    grade = 'W'
	
print ("\n\nGrade is: " + grade)

age = input("Enter  age: ")
age = int(age)
have_own_car = input("Do you have a car (y/n): ")

if (age >= 18) and (have_own_car == 'y'):
    print ("You are over 18 years has a car")
    
if (age >= 18) and (have_own_car == 'n'):
    print ("You are over 18 have no  car")

if (age < 18) and (have_own_car == 'y'):
    print ("You are too young to have a car")

if (age < 18) and (have_own_car == 'n'):
    print ("You can buy a car when you are 18")

# How can you re-write above code using if, elif,  and , or ?

#car sales program
age = input("Enter  age: ")
age = int(age)
have_own_car = input("Do you have a car (y/n): ")

if (age >= 18):
	if (have_own_car == 'y'):
		print ("Would you like to buy a new car?")
	else:
		print ("Would you like to buy a car?")
else: 
	print ("Please ask your parents to buy a car")

# while loop repeats until a condition is true
x = 1
while x < 5:  # condition for loop
	#following code  executed 4 times
    print (x)
    x = x + 1
    print ('I love python')

print ('done')

# Loop to calculate average of 3 numbers
total = 0.0 
count = 0 
while count < 3:
    number=float(input("Enter a number: "))
    count = count + 1
    total = total + number
average = total / 3
print ("The average is " + str(average))

#  counter-controlled for loop
# range (10) is 0 through 9
for i in range (10):   
    print (i)

#range (5,10) is 5 through 9
for c in range (5,10):  
    print (c)

# calculate the sum of numbers in a range
sum=0
for i in range (10):   
    sum=sum+ i
print(sum)

#break with the for loop
for c in range (1,6):
    if c == 3:
        break
    print (c)

#non stop runner
while 1:
    print ('Running? ')
    print ('Press the Ctrl + C')
    print ('to stop running')
print ('I am out of loop')
print ('done')

# breaking out of loop
while 1:
    print ('running')
    answer = input('Press y to end')
    if answer == 'y':
        print ('you stopped me?')
        break # get out of loop
		
print ('Out of loop')
print ('done!')

# continue with for
for letter in 'Python':     
   if letter == 'h':
      continue
   print 'Current Letter :', letter

#  continue with while
var = 10                    # Second Example
while var > 0:              
   var = var -1
   if var == 5:
      continue
   print 'Current variable value :', var
print "Good bye!"

for letter in 'Python': 
   if letter == 'h':
      pass
      print 'This is pass block'
   print 'Current Letter :', letter

print "Good bye!"	  

# loop in a loop, what is the out put
for num in range(10):  #to iterate between 10 to 20
   for j in range(10):
		print (i * j) 

# Loop inside a loop with while
''
First loop x < 6 repeats 5 times,
within y < 6 a loop repeats 5 times
total 25 processes run
'''
x = 1
while (x < 6):
    print () # prints a new line
    print ("x = " + str(x),) # the , prints next item on the same line                          
    x = x + 1
    y = 1
    while (y < 6):
        print ("y = " + str(y),)  
       y=y+1
       z= x * y
print (x)
print(y)
print(z)

#What will be the output of following
for i in range(5):
      print(i)

for i in range(3,6):
      print(i)

for i in range(2,10,2):
      print(i)

# loop in a loop example with  break
# print prime numbers
for num in range(10,20):  #to iterate between 10 to 20
   for i in range(2,num): #to iterate on the factors of the number
      if num%i == 0:      #to determine the first factor
         j=num/i #to calculate the second factor
         print '%d equals %d * %d' % (num,i,j)
         break #to move to the next number, the #first FOR
   else:        # else part of the loop
      print num, 'is a prime number'

# what is the output of this program	  

# Function definition 
def greeting():
    print ("Hello Friend!")
    print ("Welcome to Python!")

greeting()
greeting()
greeting()

# Function with parameters
def printme( str ):
   "I print a string passed to me"
   print (str)
   return; #  can return none

# call printme function
printme("1st call to printme function")
printme("2nd call to same function")	  

# adding function
def addTwo( a,b ):
   c=a+b
   return c; #  return value

# calling addTwo function

d=addTwo (1,3)	
print (d) 
e=addTwo (d,3)	
print (d) 
f= addTwo (d,e)
print(f)

def appendMe( mylist ):
   mylist.append([1,2,3,4]);
   print "Values inside the function: ", mylist
   return

# Now you can call changeme function
mylist = [10,20,30]
appendMe( mylist )
print "Values outside the function: ", mylist

#Example 
def changeMe( mylist ):
   mylist = [1,2,3,4] # assign new reference in mylist
   print ("Values inside the function: ", mylist)
   return

# Now you can call changeme function
mylist = [10,20,30]
print (Values before passing", mylist)
changeMe( mylist );
print (Values after passing", mylist)

#using multiple functions

def cube( y ):
    c= y * y * y
   return c

def doublecube ( z ):
    z=z * 2
     dc=cube( z) # calls cube here
 return dc

print ("Cubes")
for x in range(1,6):
    print (cube(x))
    
print ("1 to 5 doubled")
for x in range(1,6):    
    print (doublecube(x))	

#checks if a number is positive
def isPositive(x):
    if (x >= 0):
        return 1 # 1 is true
    else:
        return 0 # 0 is false
    
result = isPositive(1)
print (result)
result = isPositive(-1)
print (result)

#division by zero check
def xdivision(x,y):
    if (y == 0):
        print ("division by zero not allowed")
        return
    else:
        return x / y

result = xdivision( 5.0 , 2 )
print (result)
result = xdivision( 5.0 , 0 )
print (result)

import math # import math module

# Negative number.
n = -100.5
# Absolute value.
print(abs(n))

# Fractional number.
n = 100.7
# Absolute value.
print(math.floor(n)) # output 100.0
print(math.ceil(n)) # output 101.0

#Rounding to number of decimal places
number = 1.23456
print(round(number))
print(round(number, 0))
print(round(number, 1))
print(round(number, 2))
print(round(number, 3))

#Output
1        0 digits
1.0      0 digits
1.2      1 digit
1.23     2 digits
1.235    3 digits

# Input list.
values = [0.9999999, 1, 2, 3]
# Sum values in list.
r = sum(values)
print(r)

# Sum values with fsum.
r = math.fsum(values)
print(r)

value1 = 123.45
truncate1 = math.trunc(value1)
print(truncate1)

# sqrt function
value1 = 4
print(math.sqrt(value1))

# math.pow function
a = math.pow(2, 3)

# Use ** operator
b = 2 ** 3

# Print results
print(a)
print(b)

# returns the value of e.
print(math.e)

# returns the value of pi.
print(math.pi)

# strings and number outputs
r = 10
c = 75
print ('Total is: ', r, 'Rupees and', c, ' cents')

# %d means integer 
x = 20
y = 75
print ('The sum of %d and %d is %d' % (x, y, x + y))

# %f means float
x = 20.512
y = 15.269
print ('The sum of %f and %f is %f' % (x, y, x + y))

# % mean string
print "My name is %s and I am  %d years old!" % ('Hiruni', 19) 

%c	character
%s	string 
%d	signed decimal integer
%f	floating point real number

%i	signed decimal integer
%u	unsigned decimal integer

%o	octal integer
%x	hexadecimal integer (lowercase)
%e	exponential notation 

# what would be printed
a=2.50
b=3.42
c=5
print ("I have %d and  %d and %f !" % (a, b,c ) )

#capitalize()  - Capitalizes first letter of string
str = "this is python!";
print (str.capitalize())

#upper() - Converts to uppercase.
print (str.upper())

#lower() - Converts lowercase.
print (str.lower())

#len(string) - Returns the length of the string
print (len(str))

s = "Niranjan Meegammmana"
print(s[1])
#python use a  0 based index
print(s[0])

# access last charator
print(s[-1])

# obtain a sub string 
# from 0 to 5 , excluding 5
print(s[0:5])
# from 1 to 5 , excluding 5 
print(s[1:5])

# return pos 4 to end
print(s[4:])
print(s[:]) # whole string
# return upto 4, excluding 4
print(s[:4])
print(s[0:1])

#slice your full name into 2 parts

#isnumeric
str1 = "this2016";  
str2 = "23443434"; 
print (str1.isnumeric())
print (str2.isnumeric())

#isdigit()
print (str1.isdigit())
print (str2.isdigit())

#isalpha()
print (str1.isalpha())
print (str2.isalpha())

# split(str)
x = 'blue,red,green'
y=x.split(",") # breaks down to array of strings
print (y)
print (y[0])
#output is ['blue', 'red', 'green'] a list

#another example
a,b,c=x.split(",")
a,b,c=x.split(",")
print(a)

words = "This is some text for python"
# split with space
words2 = words.split(" ") 
print(words2)
#what will be the output

#join
s = "*";
seq = ("a", "b", "c"); # This is sequence of strings.
print s.join( seq )
# output is a*b*c

s = " ";
seq = ("a", "b", "c"); # This is sequence of strings.
print s.join( seq )
# what will be the output

words = "This is some text for python"
# split with space
words2 = words.split(" ") 
print(words2)
#what will be the output

str = "Kandy is a cool town";
str1=str.replace("Kandy", "Jaffna")
print (str1)
#output will be Jaffna is a cool town

str2=str.replace("Kandy", "Candy")
str3=str2.replace("cool", "tasty")
str4=str3.replace("town", "food")
print (str4) # what would the output?

#find
str1 = "Google is a search engine!";
str2 = "search";
print str1.find(str2)
# wi youll give 12 the character location from 0
print str1.find("Yahoo") #will return -1, if not found

#what will be the output of 
print str1.find("a")
print str1.find("a")
# 16 where to start search
print str1.find("a",16)
# 16 where to start search
print str1.find("a",16,)
# 20 is where to stop search
print str1.find("e",16,20)

myList=[1,2,3,4,5,6]
for x in myList:
	print x
# What would be the output?

# Using range() to iterate

n=len(myList)
for i in range(n):
	print myList[i] # access the element as an array
  	
	

#So the list of lists would be like this
studentList=[district1 [school1 [class1[ std1, std2,... ]]]], ...] 

append (object) - insert object to end of the list.
insert (index, object) - insert object before index.
pop ([index])- Remove and return item at index 
remove (value) - remove first occurrence of value
reverse() - Reverse the items of the list
sort () - Sort the items of the list 
count (value)  - Return number of occurrences of a value  .
index (value)  - Return index of first occurrence of value 
extend (list)  - appending a list to a list

#append
myList = [123, 'Niranjan',  8.2]
myList.append( 2016 )
print (myList)
#output is [123,'Niranjan',8.2,2016]

myList=[] # create empty list
for i in range(10):
   myList.append(i)
print (myList)
#what would be the output

myList = [1,2,3]
myList.insert(0,6) # insert 6 at 0 index
print (myList)
#output is [6, 1, 2, 3]

# remove and return last item
n=myList.pop() ; 
print (n) # output is 3
print (myList) # output is [6, 1, 2]
#remove and return item at index 2 (3rd)
n1=myList.pop(2);
print (n1) # output is 2
print (myList) #output is[6, 1]
#study the output and explain

myList = [1,2,3,4,5,"Sam", "Niranjan", "Sam"]
myList.remove(4);
print(myList)

#output is [1, 2, 3, 5, 'Sam', 'Niranjan', 'Sam']
myList.remove('Sam');
print(myList)
#output is [1, 2, 3, 5, 'Niranjan', 'Sam'] why ?

myList = [1,2,3,4,5,"Sam"]
myList.reverse();
print(myList)
#output is ['Sam', 5, 4, 3, 2, 1]

myList.sort();
print(myList)
#output is [1, 2, 3, 4, 5, 'Sam']

myList.append("Sam")
print(myList)
n=myList.count("Sam")
print(n)
#what would be the output

stack is data structure serves as a list with two main operations
push : adds an element to the top
pop: removes the most recently added element
.

Stacks use Last In First Out (LIFO) method

stack= []
stack.append(1)
stack.append("Sri Lanka")
stack.append( 4)
stack.append( "India")
print(stack)

a=stack.pop()
print(a)
print(stack)
stack.pop()
print(stack)
# analyse following outputs
[1, 'Sri Lanka', 4, 'India']
India
[1, 'Sri Lanka', 4]
[1, 'Sri Lanka']

Queue is a list data structure with two main operations
push : adds an element to the last (enque)
pop: removes the first element (deque)
.

Queues use First In First Out (FIFO) method

queue= []
queue.append(1)
queue.append("Sri Lanka")
queue.append( 4)
queue.append( "India")
print(queue)

x=queue.pop(0)
print(x)
print(queue)
y=queue.pop(0)
print(y)
print(queue)

#analyse following output
[1, 'Sri Lanka', 4, 'India']
1
['Sri Lanka', 4, 'India']
Sri Lanka
[4, 'India']

myList=[]
myList[0]=7 # will not work

myList=[2]
myList[0]=7 # will work
myList[1]=8 # will not work

#you can add an item this way
myList.append(7)

#write a program to fill a list with 100 numbers

myList=[]
for i in range(0,100):
	myList.append(i)
print (myList)

# declare a list with 10 items and
n=10
myList=[0 for i in range(n)] # 
print (myList) # elements value set to 0

#output will be 
[0, 0, 0, 0, 0, 0, 0, 0, 0, 0]

# another example check output
myList=[i*i for i in range(10)]
print (myList)
#sets myList to [0, 1, 4, 9, 16, 25, 36, 49, 64, 81].

# using a function to initialize arrays 
def dim3( n):   
   return n*n*n

print (dim3(2))
myList=[dim3(i) for i in range(10)]
print (myList)

#declare dictionary
dict = {'Name': 'Ganesh', 'Age': 17, 'Class': 12}
print (dict['Name'])
print (dict['Age'])
#the output will be
#Ganesh
#17

dict['Age'] = 18 # update existing entry
dict['Class'] = 13 # update existing entry
dict['School'] = "Ranabima Collage"; #Add new
print(dict)
#what would be the output

dict. clear - Remove all items from the dict.
dict. items  - Return all of the items in the dict as a sequence of (key,value) tuples. 
dict. keys  - Return all of the keys in the dict as a sequence of keys. 
dict. values  - Return all the values from the dict as a sequence. 

dict. pop ( key ) - Remove the given key from the dict, return the associated value
dict. get ( key) - Get the item with the given key 
dict. update ( new )  - Merge values from the new dict into the original dict

dict. copy  - Copy the dict to make a new dict. (refers to same object)
dict. setdefault ( key )  - get the item with the given key. 
dict. has_key ( key ) - Return true if key is in dict.

dict = {'Name': 'Ganesh', 'Age': 17, 'Class': 12}
print (dict['Name']) # output Ganesh
del dict['Name']
print (dict) # output 17
x=dict.get('Age') 
print(x)
dict.clear()     # remove all entries in dict
print (dict)     # output is {} empty dictionary
del dict      # delete entire dictionary
print (dict) #output nothing 

dict = {'Name': 'Ganesh', 'Age': 17, 'Class': 12}
x=dict.keys()
print (x) # output ['Name', 'Age', 'Class']

y=dict.values()
print (y) # output ['Ganesh', 17, 12]

z=dict.items()
print (z) # output [('Name', 'Ganesh'), ('Age', 17), ('Class', 12)]

dict = {'Name': 'Ganesh', 'Age': 17, 'Class': 12}
dict.pop('Class')
print(dict) # output {'Name': 'Ganesh', 'Age': 17}

dict2 = {'Sex': 'M', 'Height':5.6 }
dict.update(dict2)
print (dict)
#output is {'Name': 'Ganesh', 'Age': 17, 'Sex': 'M', 'Height': 5.6}

dict1 = {'Name': 'Ganesh', 'Age': 17}
dict2 = dict1.copy()
print (dict2)

#Return true if key is in dict.
x=dict.has_key('Age')
print(x) # output true

dict2 = dict1.copy()
print (dict2)
del dict2['Age'] # delete key Name
print (dict2)
print (dict1)

# Open a file
fo = open("myfile.txt") # open file 
fo = open("myfile.txt",) # open file 
print (fo.name) # output file name

# Open a file for writing
# wb mean write in binary mode
fo = open("myfile.txt", "wb") 
fo.write( "Python is cool\n")
fo.close() #Close file

#file opening modes
r		read only.
rb		read only in binary.
r+		reading and writing. .
rb+		reading and writing in binary.
w		writing only. 
wb		writing only in binary . 
w+		writing and reading. 
wb+		writing and reading in binary. 
a		appending. 
ab		appending in binary. 
a+		appending and reading.
ab+		appending and reading in binary . 

# Open a file
fo = open("myfile.txt", "r+") # 
str = fo.read() # read until end of file
print (str) # output 'Python is Cool'
fo.close() # Close file

fo = open("myfile.txt", "r+") # 
str = fo.read(6) # read 6 characters
print (str) # output 'Python'
fo.close() # Close file

fo = open("myfile.txt", "r+")
str = fo.read(6)
print (str)

# Check current position
position = fo.tell()
print (position)
str = fo.read(3)
print (str)
position = fo.tell()
print (position)

# Reposition pointer to beginning
position = fo.seek(0, 0)
str = fo.read(6)
print (str)
fo.close()

# Open a file
fo = open("myfile.txt", "rw+")
line = fo.readline()
print (line)
line = fo.readline(5) # read 5 characters from next line
print (line)
# Close opend file
fo.close()

fo = open("myfile.txt", "rw+")
# read all lines to a list till EOF
lines = fo.readlines() 
print (lines)
# Close opend file
fo.close()

#import os library
import os
# Rename myfile.txt to  myfile2.txt
os.rename( " myfile.txt", "myfile2.txt" )

os.remove("myfile.txt") # remove myfile.txt

os.mkdir("newdir") # Create a directory "newdir"

# Change a directory to "/home/newdir"
os.chdir("/home/newdir")

#return current working directory
os.getcwd()
os.rmdir( "/home/newdir" ) #remove /home/newdir