Welcome to Day 19 of 100 Days of Python! 🐍

In the previous lesson, we learned about while loops and how loops can repeatedly execute code based on a condition.

Today, we are going one step further and learning how to control the execution of a loop from inside the loop itself.

Python provides two important statements for this:

• break

• continue

Although both affect loop execution, they do completely different things.

• break terminates the loop completely.

• continue skips the current iteration and moves to the next iteration.

Understanding the difference between these two statements is extremely important because they are frequently used in real-world programs.

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📚 What We Will Learn

1. What is the break statement?

2. How break works

3. break with a for loop

4. Understanding the Day 19 break example

5. What is the continue statement?

6. How continue works

7. Using continue to skip unwanted values

8. break vs continue

9. Complete Day 19 program

10. Common mistakes

11. Important concepts at a glance

12. Quick revision

13. Key takeaways

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1. What is the break Statement?

The break statement is used to immediately terminate the loop in which it appears.

When Python encounters break:

break

the current loop stops immediately.

Program execution then continues with the statement after the loop.

Basic structure

for item in iterable:
    if condition:
        break

The same concept works with while loops:

while condition:
    if another_condition:
        break

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2. How Does break Work?

Consider this simple example:

for i in range(1, 11):
    if i == 5:
        break
    print(i)

Output:

1
2
3
4

When i becomes 5, this condition becomes true:

i == 5

Python executes:

break

The loop terminates immediately.

The values 6, 7, 8, 9, and 10 are never processed.

Control flow

Start loop
    ↓
Get next value
    ↓
Check condition
    ↓
Is i == 5?
  ↙       ↘
Yes       No
 ↓         ↓
break    execute body
 ↓         ↓
Exit     next iteration
loop

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3. break Terminates Only the Current Loop

The break statement terminates the nearest enclosing loop in which it occurs.

For example:

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

print("Loop finished")

When i == 5, the loop stops.

Then Python continues with:

print("Loop finished")

So break does not terminate the entire Python program.

It terminates the loop containing it.

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4. Understanding the Day 19 break Example

The first program in main.py is:

for i in range(1, 101, 1):
    print(i, end=" ")

    if i == 50:
        break
    else:
        print("Mississippi")

print("Thank you")

Let's understand it carefully.

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5. Understanding range(1, 101, 1)

The loop uses:

range(1, 101, 1)

The syntax is:

range(start, stop, step)

Therefore:

start = 1
stop = 101
step = 1

Remember:

The stop value is exclusive.

So:

range(1, 101, 1)

produces:

1, 2, 3, ..., 99, 100

The loop could theoretically reach 100, but the break statement stops it earlier.

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6. Understanding print(i, end=" ")

The program contains:

print(i, end=" ")

Normally:

print(i)

moves to the next line after printing.

But:

print(i, end=" ")

tells Python to end the output with a space instead of a newline.

Therefore, the numbers appear on the same line:

1 2 3 4 5 ...

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7. When Does the Loop Stop?

Inside the loop:

if i == 50:
    break

When:

i = 50

the condition:

i == 50

becomes True.

Python immediately executes:

break

and exits the loop.

Therefore, the loop does not continue to:

51
52
53
...
100

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8. Important Detail: Why Isn't Mississippi Printed for 50?

The code is:

if i == 50:
    break
else:
    print("Mississippi")

For values from 1 to 49, the condition:

i == 50

is false.

Therefore, the else block executes:

1 Mississippi
2 Mississippi
3 Mississippi
...
49 Mississippi

But when:

i = 50

the condition is true.

Python executes:

break

and immediately leaves the loop.

Therefore, Mississippi is not printed for 50.

So the effective output ends with:

...
49 Mississippi
50
Thank you

The tutorial's displayed output showing:

50 Mississippi

does not match the actual code.

This is an important example of why we should always trace the actual execution of a program rather than relying only on a written output example.

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9. What Happens After break?

After:

break

Python exits the loop.

The next statement is:

print("Thank you")

Therefore:

Thank you

is printed after the loop.

The complete logical flow is:

1 → print
2 → print
3 → print
...
49 → print
50 → print → break
             ↓
        exit loop
             ↓
       print Thank you

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10. What is the continue Statement?

The continue statement does something very different from break.

continue does not terminate the loop.

Instead:

continue skips the remaining statements in the current iteration and starts the next iteration.

Basic structure:

for item in iterable:
    if condition:
        continue

    # remaining code

Think of it as:

"Skip this one and move on."

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11. break vs continue

This is the most important distinction of today's lesson.

break

STOP THE LOOP

continue

SKIP THIS ITERATION
AND CONTINUE THE LOOP

For example:

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

Output:

1
2

The entire loop stops when i == 3.

Now compare:

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

Output:

1
2
4
5

Here, only the iteration for 3 is skipped.

The loop continues afterward.

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12. Understanding the Day 19 continue Example

The second program is:

for i in [2, 3, 4, 6, 8, 0]:
    if i % 2 != 0:
        continue

    print(i)

The goal is to print only the even numbers.

Let's understand why.

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13. Understanding the Modulo Operator %

The % operator returns the remainder after division.

For example:

4 % 2

gives:

0

because 4 divides evenly by 2.

But:

3 % 2

gives:

1

because 3 divided by 2 leaves a remainder of 1.

Therefore:

Even number

number % 2 == 0

Odd number

number % 2 != 0

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14. Understanding if i % 2 != 0

The code says:

if i % 2 != 0:
    continue

This means:

If the number is odd, skip the rest of this iteration.

Let's trace the list:

[2, 3, 4, 6, 8, 0]

i = 2

2 % 2 = 0

Therefore:

0 != 0 → False

continue does not execute.

So:

print(i)

runs.

Output:

2

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i = 3

3 % 2 = 1

Therefore:

1 != 0 → True

Python executes:

continue

So print(i) is skipped.

Nothing is printed for 3.

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i = 4

4 % 2 = 0

The condition is false.

Therefore:

4

is printed.

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Remaining values

The same logic applies:

6 → even → print
8 → even → print
0 → even → print

Therefore the final output is:

2
4
6
8
0

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15. Visualizing continue

The flow looks like this:

Get next value
      ↓
Check condition
      ↓
Is number odd?
   ↙        ↘
 Yes        No
  ↓          ↓
continue   print number
  ↓          ↓
Next       Next
iteration  iteration

The important part is that continue jumps directly to the next iteration.

It does not exit the loop.

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16. Complete Day 19 Program

Here is the complete main.py:

for i in range(1, 101, 1):
    print(i, end=" ")

    if i == 50:
        break
    else:
        print("Mississippi")

print("Thank you")


for i in [2, 3, 4, 6, 8, 0]:
    if i % 2 != 0:
        continue

    print(i)

This program demonstrates both major loop-control statements:

break     → terminate the loop
continue  → skip current iteration

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17. Real-World Use Cases

break and continue are not just tutorial concepts. They are useful in real programs.

Using break

You might use break when:

• Searching for an item and stopping once it is found

• Processing user input until a special value is entered

• Waiting for a valid stopping condition

• Exiting a menu loop

• Stopping a search once the required result is found

Example:

numbers = [10, 20, 30, 40, 50]

for number in numbers:
    if number == 30:
        print("Found!")
        break

Once 30 is found, there is no reason to keep searching.

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Using continue

You might use continue when:

• Skipping invalid input

• Ignoring unwanted values

• Processing only specific types of data

• Skipping empty records

• Filtering values during iteration

Example:

numbers = [1, 2, 3, 4, 5]

for number in numbers:
    if number % 2 != 0:
        continue

    print(number)

This processes only even numbers.

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18. Common Mistakes

Mistake 1: Thinking continue stops the loop

This is incorrect.

continue

does not terminate the loop.

It only skips the current iteration.

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Mistake 2: Thinking break skips one iteration

This is also incorrect.

break

terminates the loop completely.

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Mistake 3: Putting important code after continue

Consider:

for i in range(5):
    if i == 2:
        continue

    print("Value:", i)

When i == 2, Python never reaches:

print("Value:", i)

because continue immediately moves to the next iteration.

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19. break vs continue – Quick Comparison

Statement	What it does	Loop continues?
break	Terminates the current loop	❌ No
continue	Skips the current iteration	✅ Yes
break	Moves execution outside the loop	❌ No
continue	Moves to the next iteration	✅ Yes

Easy memory trick

Remember:

break = Break out of the loop

continue = Continue to the next iteration

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20. Important Concepts at a Glance

Concept	Meaning
break	Immediately exits the current loop
continue	Skips the current iteration
range()	Generates a sequence of numbers
%	Returns the remainder of division
i % 2 == 0	Checks whether i is even
i % 2 != 0	Checks whether i is odd
end=" "	Prints a space instead of a newline
for loop	Iterates over an iterable
Current iteration	The iteration currently being executed

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21. Quick Revision

break

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

    print(i)

Stops the entire loop at 5.

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continue

for i in range(10):
    if i == 5:
        continue

    print(i)

Skips 5 but continues with 6, 7, 8, and 9.

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Even-number filtering

for i in numbers:
    if i % 2 != 0:
        continue

    print(i)

Only even numbers are processed.

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22. Key Takeaways

• break is used to terminate a loop immediately.

• continue is used to skip the current iteration.

• break moves execution outside the loop.

• continue moves execution to the next iteration.

• A break can be used with both for and while loops.

• A continue can also be used with both for and while loops.

• The % operator is useful for identifying even and odd numbers.

• i % 2 == 0 identifies an even number.

• i % 2 != 0 identifies an odd number.

• In today's first example, Mississippi is printed for 1–49, but not for 50, because break executes before the else block.

• break and continue give us fine-grained control over loop execution.

Today we learned two powerful loop-control statements:

break     → Stop the loop
continue  → Skip this iteration

These may look simple, but they become extremely useful when building programs that need to search, filter, validate, skip, or terminate repeated operations intelligently.

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📂 Day 19 Resources

https://github.com/SriteshSuranjan/100-Days-of-Python/tree/main/19-Day19-break-and-continue

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