Output and Variables in Python

Output
Output is anything that your program shows on the computer screen. A python program shows or outputs a message such as  Hello World  on the computer screen, using the command print 
print ( "Hello World" )
firstNname = "Alex S."
print ( "Hello" , firstName) # shows message "Hello Alex S"
print ( "Hello %s" %firstName) # shows message "Hello Alex S"
% tells the computer to output a variable type of data, that can either be a number or a string

• %f - outputs a float number. < Ex > print ("Pi = %f, e=%f " %(3.1416, 2.71828) )
• %.2f outputs a float number rounded to two decimals. < Ex > print (" e= %.2f , Pi= %.2f " %(2.71828, 3.1416))
• %i outputs an integer. < Ex > print ("num = %i"  %3)
• %s outputs a String. < Ex > print ("Hello %s, good morning!" %firstName)
• the message above will read:      Hello Alex S. , good morning!

Variable
Variables are names for information that is temporarily stored in your computer memory (RAM).
Variable is a name such as firstName that holds a certain Data Type.  Python Variables can change their own data types.

Python Data Types:

• whole numbers ( int ) < Ex > 3 ,   101,   15...
• decimal numbers ( float ) < Ex > 3.14,    2.72,   101.181...
• strings ("  ") < Ex > "Alex S" , "Hello World!"
• lists ( [ ] ) < Ex > [ 1, 2, 3, 4, "Alex",  'c' ]

Comment - any red text line that starts with #  this part of the program is not considered as "instructions" by the compiler
Compiler - the program which turns your code into an actual program
Multiline Comment - comments that can go on multiple lines. Start and End these with three single quotes '''  '''
< Example > Output, Variables, and Data Types

Basic Programming starts here

So I have done a little bit of programming before but I am new to Python and thought I would share the info from my class and what I have learned.

• The Good Rules of Programming
  Follow these as you begin your programming studies.
  You will save time and writing code will be more enjoyable.
  

  1. Think about the logic before you write code. Write it on paper if you must.
  2. Select clear, simple, and meaningful variable names.
     • Do not use lower case L(l) or upper case i(I) , because they both look the same, and both look like 1
     • Do not user upper case O, because it looks like a zero 0
  3. Do not type all the code in at once, build slowly. 
     • Enter 3-5 lines at a time, and then test:
       • (1) Does it compile?
       • (2) Is it working?
  4. When the compiler detects an error, fix the first error (top-most) and then recompile.
     • Fixing one error (top-most)  may fix many dependent errors listed under it. 
  5. The compiler will make a guess as to the location (line) of an error. 
     • Check the location indicated by the compiler and 1 or 2 lines above. 
     • With practice, you will detect and fix the errors quickly.
  6. Best way to learn is to write code, test adjust and rerun.
  7. Be creative! There are usually *many* ways to solve the same problem!