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Python Fundamentals Part 1 Summary

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Functions

• Functions in programming perform specific tasks or actions. They have a name, parentheses, and sometimes arguments specified within the parentheses. Arguments are values provided to a function that help it carry out its task. Examples from this section:

  • print()
  • float()
  • round()

• When a function does its job, it often gives back a result. This result is called the return value. The return value may be saved to a variable or used in some expression.

Data Types

• Data types specify the kinds of data used in programming. There many built-in types, but this section starts with three basic types:
  • string - Represents a sequence of characters, used for text. Example: "Hello, World!"
  • int - Stands for integer, used for whole numbers without a decimal point. Example: 42
  • float - Represents A floating-point number, used for large and precise decimal numbers. Example: 3.14159

Output

• Console output refers to information displayed to the user in a console application.
• print() - Outputs text to the console and then moves the cursor to a new line, ready for the next output.

Arithmetic

• + Addition: Adds two numbers together.
• - Subtraction: Subtracts one number from another.
• * Multiplication: Multiplies two numbers.
• / Division: Divides one number by another and returns the quotient as a decimal.
• // Integer Division: Divides one number by another and cuts off the decimal.
• % Modulus (aka mod): Returns the remainder after division.
• Use parenthesis () for order of operations.

String Formatting

• A new way to format strings is through string interpolation. You prefix a string with the letter f. Then you use curly braces {} to insert code expressions directly within the string.

Variables

• Variables store data during a program’s execution. They can be described as containers for storing information.
• Creating a variable is called declaring a variable.
• Use the equal sign ( = ) to assign a value to a variable.
• Variables must be initialized before they can be used. This is referred to as variable scope.

Input

• input() - Allows the user to input via the keyboard. Returns the input as a string value.
  • String values do not perform arithmetic. Therefore, any user input must be converted from a string to a numeric type.

Type Conversion

• int() - Converts a specified value to an integer. Returns the integer if successful.
• float() - Converts a specified value to a floating-point (decimal) number. Returns the double if successful.
• These methods can be used to convert user input from strings to the appropriate numeric type.

Math Methods and Constants

• round() - Rounds a number to either an integer or to some decimal place
• math.sqrt() - Calculate the square root of a non-negative number.
• math.pow() - Raise a base number to the specified exponent.
• math.pi - Represents the constant value π (pi).

Random Numbers

• Random numbers are used for generating chance in games, for sample data generation, security, etc.
• The random module is used for random number generation.
  • Import the random module using import random.
  • Use the randint() function to generate a random integer within a specified range. For example, random.randint(1, 100) generates a number between 1 and 100.