Control_Statements_in_Python.pptx

Indentation in Python
• In Python, indentation is used to declare a block. If two
statements are at the same indentation level, then they are
the part of the same block.
• For the ease of programming and to achieve simplicity, python
doesn't allow the use of curly braces or parentheses for the
block level code.
• Indentation is the most used part of the python programming
language.
• Generally, a tab space or four spaces are given to indent the
statements in python.

Conditional Statements in Python

Conditional Statements in Python
• Conditional Statements performs different computations or
actions depending on conditions.
• In python, the following are conditional statements
o if
o if –else
o if – elif –else
If statement:
• The if statement is used to test a specific condition. If the
condition is true, a block of code (if-block) will be executed.
Syntax:
if condition:
statement1
statement2

Conditional Statements in Python Cont..
Example: ifdemo.py
a = 33
b = 200
if b > a:
print ("b is greater than a")
print ("done…")
Remember:
input () function is used to get input from user.
Example:
a=input (“Enter a value”)
Output:
python ifdemo.py
b is greater than a
done…

If-else statement:
• The if-else statement provides an else block combined with the if
statement which is executed in the false case of the condition.
Syntax:
if condition:
#block of statements
else:
#another block of statements (else-block)
Example: ifelsedemo.py
age = int(input("Enter your age : "))
if age>=18:
print("You are eligible to vote !!")
else:
print("Sorry! you have to wait !!"))
Output:
python ifelsedemo.py
Enter your age: 19
You are eligible to vote!!

If-elif-else statement:
• The elif statement enables us to check multiple conditions and
execute the specific block of statements depending upon the true
condition among them.
Syntax:
if condition1:
# block of statements
elif condition2:
elif condition3:
else:

Example: maxnum.py
a=int(input("Enter a value : "))
b=int(input("Enter b value : "))
c=int(input("Enter c value : "))
if (a>b) and (a>c):
print("Maximum value is :",a)
elif (b>a) and (b>c):
print("Maximum value is :",b)
else:
print("Maximum value is :",c)
Output:
python maxnum.py
Enter a value: 10
Enter b value: 14
Enter c value: 9
Maximum value is: 14

Loop Statements in Python
• Sometimes we may need to alter the flow of the program. If the
execution of a specific code may need to be repeated several
numbers of times then we can go for loop statements.
• In python, the following are loop statements
o while loop
o for loop
while loop:
• With the while loop we can execute a set of statements as long
as a condition is true. The while loop is mostly used in the case
where the number of iterations is not known in advance.
Syntax:
while expression:
Statement(s)

Loop Statements in Python Cont..
Using else with while loop
• Python enables us to use the while loop with the else block
also. The else block is executed when the condition given in
the while statement becomes false.
Example: whiledemo.py
i=1;
while i<=3:
print(i);
i=i+1;
Output:
python whiledemo.py
1
2
3
Example: wedemo.py
i=1;
while i<=3:
print(i);
i=i+1;
else:
print("while loop terminated")
Output:
python wedemo.py
1
2
3
while loop terminated

for loop:
• The for loop in Python is used to iterate the statements or a
part of the program several times. It is frequently used to
traverse the data structures like list, tuple, or dictionary.
Syntax:
for iterating_var in sequence:
statement(s)
Example: fordemo.py
i=1
n=int(input("Enter n value : "))
for i in range(i,n+1):
print(i,end = ' ')
Output:
python fordemo.py
Enter n value: 5
1 2 3 4 5

Using else with for loop
• Python allows us to use the else statement with the for loop
which can be executed only when all the iterations are
exhausted.
• Here, we must notice that if the loop contains any of the
break statement then the else statement will not be executed.
Example: fedemo.py
for i in range(1,5):
print(i,end=' ')
else:
print("for loop completely exhausted");
Output:
python fedemo.py
1 2 3 4
for loop completely exhausted

Jump Statements in Python
• Jump statements in python are used to alter the flow of a loop
like you want to skip a part of a loop or terminate a loop.
• In python, the following are jump statements
o break
o continue
break:
• The break is a keyword in python which is used to bring the
program control out of the loop.
• The break statement breaks the loops one by one, i.e., in the
case of nested loops, it breaks the inner loop first and then
proceeds to outer loops.
• The break is commonly used in the cases where we need to
break the loop for a given condition.
Syntax: break

Jump Statements in Python Cont..
continue:
• The continue statement in python is used to bring the program
control to the beginning of the loop.
• The continue statement skips the remaining lines of code inside
the loop and start with the next iteration.
• It is mainly used for a particular condition inside the loop so
that we can skip some specific code for a particular condition.
Syntax: continue
Example: breakdemo.py
i = 1
while i < 6:
print(i)
if i == 3:
break
i += 1
Output:
python breakdemo.py
1
2
3

Jump Statements in Python Cont..
Example: continuedemo.py
str =input("Enter any String : ")
for i in str:
if i == 'h':
continue;
print(i,end=" ");
Output:
python continuedemo.py
Enter any String : python
p y t o n

Control_Statements_in_Python.pptx

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Control_Statements_in_Python.pptx