View source for 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 [https://www.w3schools.com/python/python_ref_keywords.asp w3schools] for a bit more explanation and [https://docs.python.org/3/reference/ 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.
* <code>break</code> - exit the current loop
* <code>continue</code> - in a loop, go to next iteration of the loop
* <code>is</code> - determine whether two objects are the same object (not just value)
* <code>import, from</code> - to load a module
* <code>def</code> - declare a function
* <code>while</code> - loop with only condition
* <code>if, elif, else</code> - conditional statements (three keywords)
* <code>for</code> - loop with that iterates through a list
* <code>return</code> - keyword to send a value back from a function
* <code>and</code> - boolean operator, True only if both sides are True
* <code>or</code> - boolean operator, True if either side is True
* <code>not</code> - boolean operator, negates
* <code>True, False</code> - boolean values (two keywords)
* <code>del</code> - remove from a list by position
* <code>try, except</code> - handle an exception, basic use (2 keywords)
* <code>raise, assert</code> - raise/indicate an exception (2 keywords)
* <code>in</code> - test if something is inside of a list/string/tuple/dictionary
* <code>None</code> - special value for a variable that has no value
* <code>pass</code> - empty statement that does not do anything

==More Keywords==
These keywords are often not introduced or heavily used until the second Python course.
* <code>as, finally, with, else</code> - exception handling, more keywords (4 keywords)
* <code>class</code> - defining new class data type (for object-oriented programming)
* <code>lambda</code> - create unnamed / anonymous function
* <code>global, nonlocal</code> - access variables outside of current scope (2 keywords)
* <code>async, await</code> - for writing asynchronous code with asynchio package (2 keywords)
* <code>yield</code> - for creating generator functions

=Concepts=
''See [https://youtu.be/rB8jY3Y54_A this video] for a demo and explanation of basic data types and variables.
''

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
* '''<code>None</code>''' - a special value in Python that means "nothing" but is different than 0, False, and ""
* '''variable''' - name for a place in memory to store values.  Two basic things you do with a variable - (i) store a value into the variable, (ii) get the value from the variable.
* '''keywords''' - also called ''reserved'' words - these are names that should not be used for variable names because they have special meaning to python.  Example: <code>for</code> is used for loops and shouldn't be used as a variable name.
* '''function''' - also called ''procedures'' or ''methods'' - name for a block of code that does something and that your code can use when needed.  Two basic things you can do with a function - (i) define what the function is (specify the code for the function), (ii) call the function later on in your code.  Three main parts of defining function - (a) function code (called the ''body''), (b) function parameters (aka inputs), (c) function return values.  Three main parts of calling/using a function - (1) specify the parameters, (2) call the function, (3) get the return value of the function.
* '''flow chart''' - diagram that shows the steps / flow of control in a program (also used to diagram decision-making in other settings - e.g., diagnosis of an illness, managing a factory, ...)
* '''binary operator''' - operator that takes two values to produce a result.  An example is addition, 2 + 3 results in 5.  Another example is == comparison, 'hi' == 'bye' results in False because the two are not equal.
* '''unary operator''' - operator that takes one value to produce a result.  An example is Boolean not, not True results in False.
* '''operator precedence''' - rules for which operators are evaluated first in an expression.  For example, in 1 + 2 * 3, the multiplication is performed first, giving 1 + 6, and then the + is performed to result in 7.  For Python, see [https://docs.python.org/3/reference/expressions.html#evaluation-order python.org].
* '''operator associativity''' - rule whether operators of the same type are evaluated left-to-right or right-to-left.  Math operators are left-to-right.  For Python, see [https://docs.python.org/3/reference/expressions.html#evaluation-order python.org].

=Commonly Used Functions=
* <code>print</code> - function to write to the screen
* <code>int, float, str</code> - functions to convert to integer, floating point number, or string
* <code>range</code> - function to generate a sequence of numbers
* <code>len</code> - function to get the length of a string, list, or tuple