conditional_exp.py

# Python If...Else Conditional Statements
# if statements are used to execute a block of code based on a condition.
a=33
b=200
if b > a:
    print("b is greater than a")
# In this example we used two variables, a and b, which are used as the part of the if statement to check whether b is greater than a.
# If the condition evaluates to True, the code block inside the if statement is executed.
# If the condition evaluates to False, the code block inside the if statement is skipped.

# Indentation is important in Python. The code block inside the if statement must be indented.
# If the code block is not indented, Python will raise an IndentationError.
# If statement without indentation raises an error

# elif - The elif keyword is python's way of saying 'if the previous conditions were not true, then try this condition'.

a = 33
b = 200
if b > a:
    print("b is greater than a")
elif a == b:
    print("a and b are equal")

# Else - The else keyword is python's way of saying 'if the previous conditions were not true, then do this'.
a=200
b=33
if b > a:
    print("b is greater than a")
elif a == b:
    print("a and b are equal")    
else:
    print("a is greater than b")    

# You can also have an else statement without an elif statement.
a = 200 
b = 33
if b > a:
    print("b is greater than a")
else:
    print("b is not greater than a")

# one line if statement
a = 200
b = 33
if a > b: print("a is greater than b")

# one line if else statement
a=2 
b=330
print("A") if a > b else print("B")

# You can also have multiple else statements on the single line.
a=330   
b=330
print("A") if a > b else print("=") if a == b else print("B")

# And - The and keyword is a logical operator, and is used to combine conditional statements.
a = 200
b = 33
c = 500
if a > b and c > a:
    print("Both conditions are True")

# Or - The or keyword is a logical operator, and is used to combine conditional statements.
a = 200
b = 33
c = 500
if a > b or a > c:
    print("At least one of the conditions is True") 

# Nested If - You can have an if statement inside another if statement.
x=41

if x > 10:
    print("Above ten,")
    if x > 20:
        print("and also above 20!")
    else:
        print("but not above 20.")

# The pass statement - The pass statement is a null operation; nothing happens when it executes.
a=33
b=200
if b > a:
    pass  # Do nothing, just a placeholder

# Match Case Statement - Python 3.10 introduced the match-case statement, which is similar to switch-case statements in other languages.
# It allows you to match a variable against different values and execute corresponding code blocks..
day = 4
match day:
    case 1:
        print("Monday")
    case 2:
        print("Tuesday")
    case 3:
        print("Wednesday")
    case 4:
        print("Thursday")   
    case 5:
        print("Friday") 
    case 6:
        print("Saturday")
    case 7:
        print("Sunday")                

# Use the underscore character _ as the last case value if you want a code block to execute when there are not other matches.
day =4
match day:
    case 6:
        print("Today is Saturday")
    case 7:
        print("Today is Sunday")
    case _:
        print("Looking forward to the Weekend!")  # This will execute if no other case matches

# Combine values in a case using the | character.
day = 3
match day:
    case 1 | 2 | 3 | 4 | 5:
        print("It's a weekday")
    case 6 | 7:
        print("It's the weekend!")
    case _:
        print("Invalid day")

# If statement as a Guards.
# You can use an if statement as a guard in a case block to add an additional condition that must be met for that case to execute.
month =5
day =4
match day:
    case 1 | 2 | 3 | 4| 5 if month ==4:
        print("Weekday in April")
    case 1 | 2 | 3 | 4| 5 if month ==5:
        print("Weekday in May")     

# While loop
i = 1
while i < 6:
    print(i)
    i += 1  # i = i + 1

# Print x as long as x is less than 9
x = 0
while x < 9:
    print(x)
    x = x + 1  

# Exit the loop when x is 3
i = 1
while i < 6:
    print(i)
    if i == 3:
        break
    i += 1

# Continue - The continue statement is used to skip the current iteration of a loop and continue with the next iteration.
# Continue to the next iteration of the loop when i is 3 
i = 0
while i<6:
    i+=1
    if i==3:
        continue
    print(i)  

# The else block in a while loop - The else block in a while loop is executed when the condition of the while loop becomes false.
i = 1
while i < 6:
    print(i)
    i += 1
else:
    print("i is no longer less than 6")

# for loop
fruits = ["apple", "banana", "cherry"]
for x in fruits:
    print(x) 

# Looping through a string
for x in "banana":
    print(x)

# The break statement - The break statement is used to exit a for loop prematurely.
fruits = ["apple", "banana", "cherry"]
for x in fruits:
    if x == "banana":
        break  # Exit the loop when x is "banana"
    print(x)

# Exit the loop when x is 'banana' , but this time the break comes before the print:
fruits = ["apple", "banana", "cherry"]
for x in fruits:
    if x == "banana":
        break  # Exit the loop when x is "banana"
    print(x)

# The continue statement - The continue statement is used to skip the current iteration of a loop and continue with the next iteration.
fruits = ["apple", "banana", "cherry"]
for x in fruits:
    if x == "banana":
        continue  # Skip the rest of the loop when x is "banana"
    print(x)    

# The range() function - The range() function is used to generate a sequence of numbers.
# It can be used in for loops to iterate over a sequence of numbers.
for x in range(6):
    print(x) 

# Using the start parameter
for x in range(2, 6):
    print(x)

# The range() function defaults to incrementing by 1, but you can specify a different increment using the step parameter.
for x in range(2, 30, 3):
    print(x)



# Else block in a for loop - The else block in a for loop is executed when the loop completes all iterations without encountering a break statement.
for x in range(6):
    print(x)
else:
    print("Loop completed without break")

# Break the loop when x is 3, and see what happens with the else block
for x in range(6):
    if x == 3:break
    print(x)
else:
    print("Loop completed without break")

# Nested loops - A nested loop is a loop inside another loop.
adj = ["red", "big", "tasty"]
fruits = ["apple", "banana", "cherry"]
for x in adj:
    for y in fruits:
        print(x, y)

# The pass statement - The pass statement is a null operation; nothing happens when it executes.
for x in [0, 1, 2]:
    pass  # Do nothing, just a placeholder