Python Keywords, Concepts, Functions

See also Python Programming - Getting Started

Following are terse descriptions for Python3 keywords, programming concepts, and commonly used functions. For more information, see w3schools for a bit more explanation and python.org for the language reference.

Keywords

The following are heavily used in all levels of Python programming. This is a minimum set of keywords to know how to use.

• break - exit the current loop
• continue - in a loop, go to next iteration of the loop
• is - determine whether two objects are the same object (not just value)
• import, from - to load a module
• def - declare a function
• while - loop with only condition
• if, elif, else - conditional statements (three keywords)
• for - loop with that iterates through a list
• return - keyword to send a value back from a function
• and - boolean operator, True only if both sides are True
• or - boolean operator, True if either side is True
• not - boolean operator, negates
• True, False - boolean values (two keywords)
• del - remove from a list by position
• try, except - handle an exception, basic use (2 keywords)
• raise, assert - raise/indicate an exception (2 keywords)
• in - test if something is inside of a list/string/tuple/dictionary
• None - special value for a variable that has no value
• pass - empty statement that does not do anything

More Keywords

These keywords are often not introduced or heavily used until the second Python course.

• as, finally, with, else - exception handling, more keywords (4 keywords)
• class - defining new class data type (for object-oriented programming)
• lambda - create unnamed / anonymous function
• global, nonlocal - access variables outside of current scope (2 keywords)
• async, await - for writing asynchronous code with asynchio package (2 keywords)
• yield - for creating generator functions

Concepts

These are terms that we use to describe programs. These are terms that have a precise meaning when talking about programs.

• string - text data type
• boolean - data type for True and False
• floating point - data type that stores numbers with fractional parts (e.g., 3.14 or 2.2)
• integer - data type that stores only integers
• None - a special value in Python that means "nothing" but is different than 0, False, and ""

Commonly Used Functions

• print - function to write to the screen
• int, float, str - functions to convert to integer, floating point number, or string
• range - function to generate a sequence of numbers
• len - function to get the length of a string, list, or tuple