Python Tutorial (14) Control flow statements

Python Control flow statements 

What is control flow in python with Example

 Control flow in Python refers to the order in which statements are executed in a program. It allows you to make decisions, repeat actions, and control the flow of your program based on conditions. Here are some common control flow structures in Python:

if…else Statements:

Used for decision-making based on a condition.

x = 10

if x > 0:

    print(“x is positive”)

else:

    print(“x is non-positive”)

for Loops:

Used for iterating over a sequence (such as a list, tuple, or string).

fruits = [“apple”, “banana”, “cherry”]

for fruit in fruits:

    print(fruit)

while Loops:

Used for repeatedly executing a block of code as long as a condition is true.

count = 0

while count < 5:

    print(count)

    count += 1

break and continue Statements:

break is used to exit a loop prematurely.

continue is used to skip the rest of the code inside a loop and move to the next iteration.

for i in range(10):

    if i == 5:

        break

    print(i)

try…except Blocks:

Used for handling exceptions to prevent program crashes.

try:

    result = 10 / 0

except ZeroDivisionError:

    print(“Error: Division by zero”)

These examples demonstrate how control flow structures help you create more dynamic and responsive programs by allowing you to control the order in which different parts of your code are executed based on conditions and loops.

Python control flow with Example

Certainly! Let’s go through some Python control flow examples with detailed explanations:

if…else Statements:

x = 10

if x > 0:

    print(“x is positive”)

else:

    print(“x is non-positive”)

Explanation: In this example, the if statement checks if the value of x is greater than 0. If it is true, it executes the indented block under if; otherwise, it executes the block under else.

for Loops:

fruits = [“apple”, “banana”, “cherry”]

for fruit in fruits:

    print(fruit)

Explanation: This for loop iterates over the list of fruits and prints each fruit on a new line.

while Loops:

count = 0

while count < 5:

    print(count)

    count += 1

Explanation: The while loop continues to execute the indented block as long as the condition (count < 5) is true. It prints the current value of count and increments it in each iteration.

break and continue Statements:

for i in range(10):

    if i == 5:

        break

    print(i)

Explanation: The break statement is used to exit the loop when i becomes equal to 5. It prints values from 0 to 4 and then exits the loop.

try…except Blocks:

try:

    result = 10 / 0

except ZeroDivisionError:

    print(“Error: Division by zero”)

Explanation: The try block attempts to perform a division operation, which would raise a ZeroDivisionError. The except block catches this specific exception and prints an error message.

These examples showcase how control flow structures in Python (if, for, while, break, continue, try, except) can be used to control the flow of a program based on conditions, loops, and handle exceptions.

what is Control flow diagram with Example

A control flow diagram (also known as a flowchart) is a visual representation of the sequence of steps or operations in a program, process, or algorithm. It uses different shapes to represent different types of actions and connectors to show the flow of control between them. Here’s a simple example of a control flow diagram:

Example: Guess the Number Game

Let’s create a control flow diagram for a simple “Guess the Number” game:

Start:

The starting point of the game.

Generate a Random Number:

Action: Generate a random number between 1 and 100.

Initialize Guess Counter:

Action: Set the guess counter to 0.

Ask for User Input:

Action: Prompt the user to guess the number.

Increment Guess Counter:

Action: Increase the guess counter by 1.

Check Guess:

Decision: Is the guessed number correct?

Yes: Go to “End – Correct Guess.”

No:

Is the guess counter less than 5?

Yes: Go back to “Ask for User Input.”

No: Go to “End – Incorrect Guess.”

End – Correct Guess:

Action: Display a congratulatory message.

End – Incorrect Guess:

Action: Display a message indicating the correct number.

End:

The end point of the game.

Here’s a simplified representation using text:

+————————+

| Start                  |

+————————+

        |

+————————+

| Generate a Random      |

| Number                 |

+————————+

        |

+————————+

| Initialize Guess       |

| Counter                |

+————————+

        |

+————————+

| Ask for User Input     |

+————————+

        |

+————————+

| Increment Guess        |

| Counter                |

+————————+

        |

+————————+

| Check Guess            |

|                        |

| Is guessed number      |

| correct?               |

|   |                    |

|   Yes                  |

|   |——————–|

|   |                    |

|   No                   |

|   |——————–|

|   |                    |

|   Is guess counter     |

|   less than 5?         |

|     |                  |

|     Yes                |

|     |——————|

|     |                  |

|     No                 |

|     |——————|

|     |                  |

|     End – Incorrect    |

|     Guess              |

+————————+

        |

+————————+

| End – Correct Guess   |

+————————+

        |

+————————+

| End – Incorrect Guess |

+————————+

        |

+————————+

| End                    |

+————————+

In this flowchart, rectangular boxes represent actions, diamonds represent decision points, and arrows represent the flow of control. It provides a visual representation of the steps involved in the “Guess the Number” game and the logic for handling correct and incorrect guesses.

What is Control flow statements  in Python with Example?

Control flow statements in Python are used to control the flow of execution in a program. They allow you to make decisions, repeat actions, and handle exceptions. Here are some key control flow statements in Python with examples:

if…else Statements:

Used for decision-making based on a condition.

x = 10

if x > 0:

    print(“x is positive”)

else:

    print(“x is non-positive”)

for Loops:

Used for iterating over a sequence (such as a list, tuple, or string).

fruits = [“apple”, “banana”, “cherry”]

for fruit in fruits:

    print(fruit)

count = 0

while count < 5:

    print(count)

    count += 1

break and continue Statements:

break is used to exit a loop prematurely.

continue is used to skip the rest of the code inside a loop and move to the next iteration.

for i in range(10):

    if i == 5:

        break

    print(i)

try…except Blocks:

Used for handling exceptions to prevent program crashes.

try:

    result = 10 / 0

except ZeroDivisionError:

    print(“Error: Division by zero”)

elif (else if) Statements:

Used to check multiple conditions in sequence.

score = 75

if score >= 90:

    print(“A”)

elif 80 <= score < 90:

    print(“B”)

elif 70 <= score < 80:

    print(“C”)

else:

    print(“F”)

These examples demonstrate how control flow statements in Python help you create more dynamic and responsive programs by allowing you to control the order in which different parts of your code are executed based on conditions, loops, and exceptions.

What is isotype control flow Cytometry

Isotype control in flow cytometry is a crucial component used to interpret and analyze the results obtained from the staining of cells with fluorochrome-conjugated antibodies. Flow cytometry is a technique that allows the simultaneous measurement of various physical and chemical characteristics of individual cells as they flow in a fluid stream through a beam of light.

In flow cytometry, antibodies labeled with fluorochromes are commonly used to identify specific cell surface markers or intracellular proteins. Isotype controls are a type of control used to distinguish specific staining from non-specific background signal. Here’s how isotype controls work:

Antibodies and Isotype Controls:

Antibodies are proteins that can specifically bind to target molecules (antigens). In flow cytometry, antibodies are often labeled with fluorescent dyes, and they are used to identify specific cell types or proteins.

Isotype controls are antibodies of the same isotype (class) as the specific antibody of interest but are directed against an irrelevant antigen. They are used as a control to account for non-specific binding and background fluorescence.

Purpose of Isotype Controls:

Isotype controls help researchers distinguish between specific binding of the antibody of interest and non-specific binding. Non-specific binding can occur due to interactions with Fc receptors on cells or other factors, leading to false-positive results.

Experimental Design:

When conducting a flow cytometry experiment, researchers typically include isotype controls alongside their specific antibodies. Cells are divided into groups, with one group receiving the specific antibody and another receiving the isotype control.

Data Analysis:

During data analysis, the fluorescence signal obtained from the specific antibody-stained cells is compared to the signal obtained from cells stained with the isotype control.

The isotype control signal represents the background or non-specific binding. By subtracting the isotype control signal from the specific antibody signal, researchers can identify and quantify the specific binding of the antibody to its target.

In summary, isotype controls in flow cytometry serve as essential controls to distinguish specific antibody binding from non-specific background signal. They are an integral part of experimental design and data analysis in flow cytometry studies, ensuring accurate and reliable interpretation of results.

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