Python Keywords, Concepts, Functions

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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 for the language reference.


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


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

Python 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