Bio 5.4

• Every value in Python possesses a data type.
• The data type influences the permitted operations.
• Python employs dynamic typing, negating the necessity for explicit data type declarations, instead, the interpreter infers the type.

Common Data Types

• Numerical:
  • int (integer): Examples include 4, -100, and 0.
  • float (floating point): Examples include 3.14, -2.5, and 0.0.
• Textual:
  • str (string): Examples include "Hello", 'World', and "123".
• Boolean:
  • bool (boolean): Can be either True or False.

Type Conversion

• Implicit Conversion: Python automatically facilitates conversions between certain data types.
• Example: When summing an int and a float, the int is converted to a float.

result = 3 + 2.5 # result is 5.5 (float)

• Explicit Conversion (Casting): Functions such as int(), float(), str(), and bool() can be employed to convert between data types.

x = int("123") # x is 123 (integer)
y = str(3.14)   # y is "3.14" (string)
z = bool(0)    # z is False (boolean)

Operators

• Symbols that execute operations on values also known as operands.

Arithmetic Operators

• +: Addition. Example: x + y
• -: Subtraction. Example: x - y
• *: Multiplication. Example: x * y
• /: Division. Example: x / y
• //: Floor Division. Example: x // y
• %: Modulus (remainder). Example: x % y
• **: Exponentiation. Example: x ** y

Comparison Operators

• ==: Equal to. Example: x == y
• !=: Not equal to. Example: x != y
• >: Greater than. Example: x > y
• <: Less than. Example: x < y
• >=: Greater than or equal to. Example: x >= y
• <=: Less than or equal to. Example: x <= y

Logical Operators

• and: Returns True if both operands are True. Example: x and y
• or: Returns True if at least one operand is True. Example: x or y
• not: Returns the opposite boolean value. Example: not x

Assignment Operators

• =: Assigns a value. Example: x = 5
• +=: Adds and assigns. Example: x += 2 (x = x + 2)
• -=: Subtracts and assigns. Example: x -= 2 (x = x - 2)
• *=: Multiplies and assigns. Example: x *= 2 (x = x * 2)
• /=: Divides and assigns. Example: x /= 2 (x = x / 2)

Expressions and Statements

• Expression: A combination of values, variables, and operators that produces a value.
• Statement: A unit of code that performs an action.

Control Flow

• Governs the order in which statements are executed.

Conditional Statements

• if, elif, else are used for decision-making.

x = 10

if x > 0:
    print("Positive")
elif x < 0:
    print("Negative")
else:
    print("Zero")

Loops

• for and while loops are used for repetitive execution of code blocks.

for i in range(5):
    print(i) # Prints 0 to 4

## While loop
count = 0
while count < 5:
    print(count) # Prints 0 to 4
    count += 1

number = 17

if number % 2 == 0:
    print("Even")
else:
    print("Odd")

  # Output: Odd

Summary

• Data types: int, float, str, bool
• Type conversion: Implicit and explicit
• Operators: Arithmetic, comparison, logical, assignment
• Expressions and statements
• Control flow: Conditional statements and loops