for var in sequence:
if condtion:

A loop placed within another loop is called as nested loop structure. A while; within another while; for within another for; for within while and while within for to construc nested loops.

Syntax:
for counter_variable in sequence:
statements-block 1
[else: # optional block
statement-block 2]

Syntax:
variable = variablel if condition else variable 2

The range() is a built-in function, to generate series of values between two numeric intervals.
The syntax of range() is as follows:
range (start,stop,[step])
Where,
start - refers to the initial value
stop - refers to the final value
step - refers to increment value, this is optional part.

A program statement that causes a jump of control from one part of the program to another is called control structure or control statement.

Syntax:
if < condition >:
          statements-block 1
else:
          statements-block 2

There are three important control Structures
(i) Sequential
(ii) Alternative or Branching
(iii) Iterative or Looping

for var in sequence:
# code inside for loop
if condition:

while test expression:
#code inside while loop
if condition:

Python provides the following types of alternative or branching statements:
(i) Simple if statement
(ii) if..else statement
(iii) if..elif statement

(i) The if.. else statement provides control to check the true block as well as the false block,
(ii) Syntax :
     if <condition> :
           statemets-block 1
     else :
           statement-block 2
(iii) if..else statement thus provides possibilities and the condition  determines which BLOCK is to be executed.

for i in range (1, 6) :
for j in range (65, 65 + i)
         a = chr(j)
print a
print

Multiplication table :
num =int(input("Enter the number: "))
print("multiplication Table of", num)
for i in range(1,11):
        print (num,"x",i, "= ",num*i )
Output :
Enter the number : 6
Multiplication Table of 6
6 x 1 = 6
6 x 2 = 12
6 x 3 = 18
6 x 4 = 24
6 x 5 = 30
6 x 6 = 36
6 x 7 = 42
6 x 8 = 48
6 x 9 = 54
6 x 10 = 60.

Nested if..elif..else statement :
(i) When we need to construct a chain of if statement(s) then 'elif' clause can be used instead of 'if else'.
(ii) Syntax:
if < condition - 1>:
      statements-block 1
elif < condition - 2>:
       statements-block 2
else:
       statements-block n
(iii) In the syntax of if..elif ..else mentioned above, condition -1 is tested if it is true then statements-block 1 is executed, otherwise, the control checks condition-2, if it is true statements-block 2 is executed and even if it fails statements-block n mentioned in else part is executed.

(iv) 'elif' clause combines if..else-if ..else statements to one if..elif ... else. 'elif' can be considered to be abbreviation of 'else if'. In an 'if' statement there is no limit of 'elif' clause that can be used, but an 'else' clause if used should be placed at the end.
(v) Example: # Program to illustrate the use of nested if statement

m1 = int (input("Enter mark in first subject:"))
m2 = int (input("Enter mark in second subject:"))
avg = (m1+m2)/2
if avg > =80:
   print ("Grade : A")
elif avg > =70 and avg < 80:
   print ("Grade : B")
elif avg > =60 and avg < 70:
   print ("Grade : C")
elif avg > =50 and avg < 60:
   print ("Gradec: D")
else:
   print("Grade : E")
Output 1:
Enter mark in first subject : 34
Enter mark in second subject : 78
Grade : D
Output 2:
Enter mark in first Subject : 67
Enter mark in  second subject : 73
Grade: B