Python Cheat Sheet
Students need to be aware of 4 data types:
- String ➔ “this is a string” ; you can use either single quotes ‘ ‘ or double quotes ” “
- Integer ➔ 12 ; an integer is a whole number, such as 12, 0 or -4
- Float ➔ 3.14 ; a float is any number with decimals
- Boolean ➔ True ; note True and False require a capital T or capital F
Colors in the Codesters text editor are related to type:
- “strings are green”
- numbers like 12 or 3.14 are blue
- Booleans like True and False are red
- variable names are orange
- everything else is white including functions, classes, punctuation, and reserved words
MATH AND RANDOM (see the Math section of the Toolkit for more)
6 + 3 ➔ 9 + addition
6 – 3 ➔ 3 – subtraction
6 * 3 ➔ 18 * multiplication
6 / 3 ➔ 2 / division
7 % 3 ➔ 1 % remainder (modulo)
6 ** 3 ➔ 196 ** exponent
random.randint(1, 10) ➔ creates a random integer between 1 and 10
random.rand() ➔ creates a random float (decimal) between 0 and 1
“Hello” + ” world!” ➔ Hello world! +combine two strings
“I am “ + str(13) ➔ I am 13 str( ) when combining a string and an integer with +
Variables let you store a piece of data to use later. This data can also change over the course of a program, so it’s useful for keeping track of things like scores. To create a variable, just type the name of the variable followed by an equals sign and a value. For example:
- fav_class = “coding”
- score = 14
3 rules for naming variables:
1) Do not put variable names in quotes
2) Variable names cannot contain spaces, use underscores _ instead
3) Variable names cannot begin with numbers
- “result” = 12 ; must be ➔ result = 12
- my name = “Codesters” ; must be ➔ my_name = “Codesters”
- 3rd_example = True ; must be ➔ third_example = True
BLOCKS (If statements, Loops, Functions, and Events)
If Statements let you execute or skip a group of commands depending on whether the condition you provide is true or false.
- For example – this tests whether you guess the correct answer “blue”.
- You can use the following comparisons and logical operations:
== equal != not equal
> greater than >= greater than or equal to
< less than <= less than or equal to
Loops let you execute a group of commands multiple times.
- For example – this tells the sprite to count to 5.
- For example – this tells the sprite to say each letter in “Codesters”.
Functions let you create a group of commands that you can run later.
- For example, this function squares a number, says the square, then returns the result.
Events let you create a group of commands that will run when certain things happen on the stage, or the user presses a particular button.
Whitespace and formatting blocks
- Python is very particular about whitespace. All code inside of these blocks must be indented four spaces.
- Codesters will highlight the whitespace in these blocks. If your highlighting is missing, check your whitespace.
- The first line of all these blocks always ends in a colon.