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Python Syntax: Variables, Data Types, Conditionals, Loops

Variables and Data Types

Python is a dynamically typed programming language, meaning you do not need to declare variable types before using them. Below are examples of variable declaration and some common data types:

Variable declaration:

variable_name = value

Common data types:

  • Integer (int): age = 25
  • Floating-point number (float): pi = 3.14
  • String (str): name = "John"
  • Boolean (bool): is_true = True

 

Conditional Statements

Conditional statements in Python are used to check conditions and execute statements based on the evaluation result. The if, else, and elif (else if) structures are used as follows:

if statement:

if condition:
    # Execute this block if condition is True

else statement:

else:
    # Execute this block if no preceding if statement is True

elif (else if) statement:

elif condition:
    # Execute this block if condition is True and no preceding if or else statement is True

 

Loops

Python supports two commonly used loop types: for loop and while loop, enabling repetitive execution of statements.

for loop:

for variable in sequence:
    # Execute statements for each value in the sequence

while loop:

while condition:
    # Execute statements while the condition is True

 

Specific Example:

# Variable declaration
age = 25
name = "John"

# Conditional statement
if age >= 18:
    print("You are of legal age.")
else:
    print("You are not of legal age.")

# Loop
for i in range(5):
    print("Hello there!")

count = 0
while count < 5:
    print("Loop number:", count)
    count += 1

When executed, the above code will check the age and print the appropriate message, then loop the Hello there! message five times using a for loop, and finally print the values of the while loop.