Python basics Notes as per aktu syllabus unit-1

This is the notes for the python basics.

1. CONDITIONALSTATEMENTS
Decisionmakingisanticipationofconditionsoccurringwhileexecution
oftheprogramandspecifying actionstakenaccordingtotheconditions.
Followingisthegeneralformofatypicaldecisionmakingstructurefound
in mostoftheprogramminglanguages−
Pythonprogramminglanguage
assumes
zeroand
any non-
non-nullvaluesas
TRUE,
and
ifitiseitherzeroornull,then
itisassumedasFALSEvalue.

2. Pythonprogramminglanguageprovidesfollowing
typesofdecisionmakingstatements:
•Ifstatements:
•
Anifstatementconsistsofabooleanexpression
followedbyoneormorestatements.
•
If-elsestatements:
•
Anifstatementcanbefollowedbyanoptional else
statement,whichexecuteswhenthebooleanexpression
isFALSE.•
Nestedifelse statements:
•
Youcanuseone iforelseifstatementinside
anotheriforelseifstatement(s).
CONDITIONALSTATEMENTS

3. CONDITIONALSTATEMENTS
Ifstatements:
Syntax:
if(expression):
statement(s)
Ex:
val=5
if(val==5):
print("Iamfive")
OUTPUT:

4. CONDITIONALSTATEMENTS
Ifstatements:
EX:ProgramtocheckthegivennumberisNegative
num=float(input("Enterthenumber::"))
ifnum<0:
print("Thenumber{0} is Negative:".format(num))
OUTPUT:

5. CONDITIONALSTATEMENTS
If-elsestatements:
Syntax:
if(expression):
statement(s)
else:
statement(s)
Ex:
val=6
if(val==5):
print("Iamfive")
else:
print(“Iamnotfive”)
OUTPUT:

6. CONDITIONALSTATEMENTS
If-elsestatements:
EX: ProgramtocheckthegivennumberisPositiveorNegative
num=float(input("Enterthenumber::"))
ifnum<0:
print("Thenumber{}isNegative:".format(num))
else:
print("Thenumber{}isPositive:".format(num))
OUTPUT:

7. If-elif-elsestatements:
Syntax:
CONDITIONALSTATEMENTS
if (expression):
statement(s)
elif(exp):
statement(s)
else:
statement(s)
Ex:
val=10
ifval>10:
print("Value is greaterthan10")
elif(val<10):
print("value is less than 10")
else:
print("Valueis equalto 10")
OUTPUT:

8. CONDITIONALSTATEMENTS
If-elif-elsestatements:
EX:ProgramtocheckthegivenYearis LeaporNot
year=int(input("Entertheyear::"))
ifyear%400==0andyear%100==0:
print("Theyear{0} isLeapyear.".format(year))
elifyear%4==0andyear%100!=0:
print("Theyear{0}isLeapyear.".format(year))
else:
print("Theyear{0}is NOTLeapyear.".format(year))
OUTPUT:

9. NestedIf-elsestatements:
Syntax:
ifexpression1:
statement(s)
CONDITIONALSTATEMENTS
if expression2:
statement(s)
elifexpression3:
statement(s)
else:
statement(s)
else:
statement(s)
var=100
ifvar<200:
print(“Valueislessthan200”)
ifvar==150:
print(“Whichis150”)
elifvar==100:
print(“Whichis100”)
else:
print(“Thisisinnerelse”)
else:
print(“Thisisoutelsepart”)

10. CONDITIONALSTATEMENTS
NestedIf-elsestatements:
EX: Programtocheck thelargestnumberofgiventhreenumbers
num1=float(input("Enter the First number:: "))
num2=float(input("Enter the Second number:: "))
num3=float(input("EntertheThird number::"))
ifnum1>num2:
if(num1>num3):
print("Thenumber{} isthelargestnumber.".format(num1))
else:
print("The number {} is the largest number.".format(num3))
elif(num2>num3):
print("Thenumber{} isthelargestnumber.".format(num2))
else:
print("Thenumber{} isthelargestnumber.".format(num3))

11. Example:
1.Write a program to find small number of two numbers (if)
2.Write a Program to input age and check whether the person is eligible to vote or not.
3.Write a program to find biggest number among three numbers.

12. Python For Loops
PythonForLoops
•Aforloopisusedforiteratingoverasequence
(thatiseitheralist,atuple,adictionary,aset,ora
string).
•Thisislessliketheforkeywordinother
programminglanguages,andworksmorelikean
iteratormethodasfoundinotherobject-orientated
programminglanguages.
•Withtheforloopwecanexecuteasetof
statements,onceforeachiteminalist,tuple,set
etc.

13. Example
Print each fruit in a fruit list:
fruits = ["apple", "kiwi", "cherry"]
for x in fruits:
print(x)

14. Python While Loops

15. Looping Through a String
Even strings are iterable objects, they contain a sequence of
characters:
Example
Loop through the letters in the word "banana":for x in "banana":
print(x)

16. The pass Statement
•ifstatements cannot be empty, but if you for some reason have
an ifstatement with no content, put in the passstatement to
avoid getting an error.
•Example
a = 33
b = 200
if b > a:
pass

17. The break Statement
•With the break statement we can stop the loop even if the
while condition is true:
•Example
Exit the loop when iis 3:i= 1
while i< 6:
print(i)
if i== 3:
break
i+= 1

18. The break Statement
fruits = ["apple", "banana", "cherry"]
for x in fruits:
print(x)
if x == "banana":
break

19. The continue Statement
•With the continue statement we can stop the current iteration,
and continue with the next:
•Example
Continue to the next iteration if iis 3:i= 0
while i< 6:
i+= 1
if i== 3:
continue
print(i)

20. fruits = ["apple", "banana", "cherry"]
for x in fruits:
if x == "banana":
continue
print(x)
The continue Statement
The continue Statement

21. The range() Function
Example
Using the range() function:
for x in range(6):
print(x)

22. for x in range(2, 6):
print(x)

23. Nested Loops
•A nested loop is a loop inside a loop.
•The "inner loop" will be executed one time for each iteration
of the "outer loop":
adj = ["red", "big", "tasty"]
fruits = ["apple", "banana", "cherry"]
for x in adj:
for y in fruits:
print(x, y)