Python control statements
Python control statements
Control statements in Python are used to control the flow of a program's execution. They determine which blocks of code should be executed under certain conditions, allowing you to create logic and make decisions in your Python programs. Python provides several control statements, including:
1. Conditional Statements:
- if: The `if` statement is used to execute a block of code only if a certain condition is true.
```python
if condition:
# Code to execute if the condition is true
```
- if-else: The `if-else` statement allows you to execute one block of code if a condition is true and another block if the condition is false.
```python
if condition:
# Code to execute if the condition is true
else:
# Code to execute if the condition is false
```
- if-elif-else: The `if-elif-else` statement is used when you have multiple conditions to check, and it allows you to specify different blocks of code for each condition.
```python
if condition1:
# Code to execute if condition1 is true
elif condition2:
# Code to execute if condition2 is true
else:
# Code to execute if no condition is true
```
2. Looping Statements:
- for: The `for` loop is used to iterate over a sequence (e.g., a list, tuple, or string) and execute a block of code for each element in the sequence.
```python
for element in sequence:
# Code to execute for each element
```
- while: The `while` loop repeatedly executes a block of code as long as a specified condition is true.
```python
while condition:
# Code to execute while the condition is true
```
3. Control Flow Statements:
- break: The `break` statement is used to exit a loop prematurely, even if the loop condition is still true.
```python
for element in sequence:
if condition:
break
```
- continue: The `continue` statement is used to skip the rest of the current iteration in a loop and move to the next iteration.
```python
for element in sequence:
if condition:
continue
```
- pass: The `pass` statement is a placeholder that does nothing. It is often used when a statement is syntactically required but no action is needed.
```python
if condition:
pass
```
4. Exception Handling:
- try-except: The `try-except` statement allows you to handle exceptions (errors) gracefully by providing alternative code to execute when an exception occurs.
```python
try:
# Code that may raise an exception
except ExceptionType:
# Code to handle the exception
```
- try-except-else-finally: This extended version of the `try-except` statement allows you to specify code to execute after the `try` block (if no exceptions occur) and after the `except` block (regardless of whether an exception occurred).
```python
try:
# Code that may raise an exception
except ExceptionType:
# Code to handle the exception
else:
# Code to execute if no exception occurred
finally:
# Code to execute regardless of exceptions
```
These control statements are essential for creating conditional logic, loops, and handling exceptions in Python programs. They provide the flexibility to control the flow of your code based on various conditions and events.
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