Key Concepts

Review core concepts you need to learn to master this subject

Comments

print() Function

Strings

Variables

Errors

SyntaxError

NameError

ZeroDivisionError

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Comments

# Comment on a single line

user = "JDoe" # Comment after code

A comment is a piece of text within a program that is not executed. It can be used to provide additional information to aid in understanding the code.

The # character is used to start a comment and it continues until the end of the line.

Hello World
Lesson 1 of 1
  1. 1
    Welcome
    Python is a programming language. Like other languages, it gives us a way to communicate ideas. In the case of a programming language, these ideas are “commands” that people use to communicate with…
    Start
  2. 2
    Comments
    Ironically, the first thing we’re going to do is show how to tell a computer to ignore a part of a program. Text written in a program but not run by the computer is called a comment. Python inter…
    Start
  3. 3
    Print
    Now what we’re going to do is teach our computer to communicate. The gift of speech is valuable: a computer can answer many questions we have about “how” or “why” or “what” it is doing. In Python, …
    Start
  4. 4
    Strings
    Computer programmers refer to blocks of text as strings. In our last exercise, we created the string “Hello world!”. In Python a string is either surrounded by double quotes (“Hello world”) or si…
    Start
  5. 5
    Variables
    Programming languages offer a method of storing data for reuse. If there is a greeting we want to present, a date we need to reuse, or a user ID we need to remember we can create a variable whic…
    Start
  6. 6
    Errors
    Humans are prone to making mistakes. Humans are also typically in charge of creating computer programs. To compensate, programming languages attempt to understand and explain mistakes made in their…
    Start
  7. 7
    Numbers
    Computers can understand much more than just strings of text. Python has a few numeric data types. It has multiple ways of storing numbers. Which one you use depends on your intended purpose for …
    Start
  8. 8
    Calculations
    Computers absolutely excel at performing calculations. The “compute” in their name comes from their historical association with providing answers to mathematical questions. Python performs addition…
    Start
  9. 9
    Changing Numbers
    Variables that are assigned numeric values can be treated the same as the numbers themselves. Two variables can be added together, divided by 2, and multiplied by a third variable without Python di…
    Start
  10. 10
    Exponents
    Python can also perform exponentiation. In written math, you might see an exponent as a superscript number, but typing superscript numbers isn’t always easy on modern keyboards. Since this operatio…
    Start
  11. 11
    Modulo
    Python offers a companion to the division operator called the modulo operator. The modulo operator is indicated by % and gives the remainder of a division calculation. If the number is divisible, t…
    Start
  12. 12
    Concatenation
    The + operator doesn’t just add two numbers, it can also “add” two strings! The process of combining two strings is called string concatenation. Performing string concatenation creates a brand ne…
    Start
  13. 13
    Plus Equals
    Python offers a shorthand for updating variables. When you have a number saved in a variable and want to add to the current value of the variable, you can use the += (plus-equals) operator. # Firs…
    Start
  14. 14
    Multi-line Strings
    Python strings are very flexible, but if we try to create a string that occupies multiple lines we find ourselves face-to-face with a SyntaxError. Python offers a solution: multi-line strings. By…
    Start
  15. 15
    Review
    In this lesson, we accomplished a lot of things! We instructed our computers to print messages, we stored these messages as variables, and we learned to update those messages depending on the part …
    Start

What you'll create

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How you'll master it

Stress-test your knowledge with quizzes that help commit syntax to memory

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