Hello Friends,

Python Operators

Arithmetic Operators

a = 10
b = 5

print(a + b)
print(a - b)
print(a * b)
print(a / b)

Comparison Operators

print(a > b)
print(a == b)

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Conditional Statements in Python

Conditional statements control the flow of execution.

Example

marks = 75

if marks >= 60:
    print("First Division")
elif marks >= 40:
    print("Second Division")
else:
    print("Fail")

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Loops in Python

For Loop

for i in range(1, 6):
    print(i)

Python for Loop

The for loop in Python is used to iterate (loop) over a sequence such as a list, tuple, string, or range of numbers. It executes a block of code repeatedly for each item in the sequence.

Syntax of for Loop

for variable in sequence:
    statements

variable – takes value of each element in the sequence
sequence – list, tuple, string, or range
statements – code executed for each iteration

Example 1: for Loop with range()

The range() function generates a sequence of numbers.

for i in range(1, 6):
    print(i)

Output:

Explanation:
The loop runs 5 times. The variable i takes values from 1 to 5.

Example 2: for Loop with List

fruits = ["apple", "banana", "mango"]

for fruit in fruits:
    print(fruit)

Output:

apple
banana
mango

Explanation:
Each element of the list is assigned to the variable fruit one by one.

Example 3: for Loop with String

name = "Python"

for char in name:
    print(char)

Output:

P
y
t
h
o
n

Explanation:
Strings are sequences of characters. The loop iterates over each character.

Example 4: for Loop with range(start, stop, step)

for i in range(0, 11, 2):
    print(i)

Output:

Explanation:
The loop starts at 0, ends at 10, and increments by 2.

Example 5: Nested for Loop

A nested for loop means one loop inside another.

for i in range(1, 4):
    for j in range(1, 4):
        print(i, j)

Output:

Example 6: for Loop with break

The break statement stops the loop immediately.

for i in range(1, 10):
    if i == 5:
        break
    print(i)

Output:

Example 7: for Loop with continue

The continue statement skips the current iteration.

for i in range(1, 6):
    if i == 3:
        continue
    print(i)

Output:

Example 8: for Loop with else

The else block executes when the loop finishes normally.

for i in range(1, 4):
    print(i)
else:
    print("Loop completed successfully")

Output:

1
2
3
Loop completed successfully

Real-Life Example

Printing student marks:

marks = [65, 72, 80, 90]

for mark in marks:
    print("Student scored:", mark)

Common Mistakes

Missing colon : after for statement
Incorrect indentation
Using wrong variable name inside loop

Summary

for loop is used to iterate over sequences
range() is commonly used with for loops
Supports break, continue, and else
Very useful in automation and data processing

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While Loop

i = 1
while i <= 5:
    print(i)
    i += 1

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What is "is" in Python? | is vs == Explained

What is `is` in Python?

In Python, is is an identity operator used to check whether two variables refer to the same object in memory. Unlike the == operator, which compares values, is compares object identity.

Definition of `is` Operator

The is operator returns True if both variables point to the same memory location, otherwise it returns False.

Syntax:

x is y

Difference Between `is` and `==`

is	==
Checks memory identity	Checks value equality
Compares object reference	Compares data/content
Used for singletons	Used for value comparison
x is y	x == y

Example 1: Using `is` with Integers

x = 10
y = 10

print(x == y)   # True
print(x is y)   # True

Python caches small integers (usually from -5 to 256). So both x and y refer to the same memory object.

Example 2: When `==` is True but `is` is False

x = 1000
y = 1000

print(x == y)   # True
print(x is y)   # False

Here, the values are equal, but Python creates separate objects in memory.

Example 3: `is` with Lists

a = [1, 2, 3]
b = [1, 2, 3]

print(a == b)   # True
print(a is b)   # False

Lists are mutable objects, so Python does not reuse memory for them.

Example 4: Using `is` with `None`

The most common and recommended use of is is checking against None.

x = None

if x is None:
    print("x is None")

❌ Bad Practice:

if x == None:
    pass

✔ Best Practice:

if x is None:
    pass

Using `id()` to Understand `is`

The id() function returns the memory address of an object.

x = 10
y = 10

print(id(x))
print(id(y))

If both IDs are same, is will return True.

When Should You Use `is`?

To compare with None
To check singleton objects
To verify object identity

When NOT to Use `is`?

For string comparison
For numeric value comparison
For list or dictionary value comparison

Interview Questions on `is` Operator

What is the difference between is and ==?
Why should we use is with None?
Does is compare values?
What does id() return?

Summary

is checks object identity, not value
== checks value equality
is compares memory references
Use is mainly with None

✅ Understanding is helps avoid logical bugs and improves Python coding best practices.

Related Topics: == vs is, id() function, Mutable vs Immutable Objects, Python Operators

Cross_Column

Sunday, 18 January 2026