ex22

go back through every exercise you have done so far and write down every word and symbol
(another name for "character") that you have used.
Make sure your list of symbols is complete.
Next to each word or symbol, write its name and what it does.


print()                     - The print() function writes the value of the argument(s) it is given
#                           - one line comment
""" """                     - multiple lines comment
+                           - addition
-                           - substraction
/                           - division, continuation character
*                           - multiplication
%                           - remainder
<                           - less-than
>                           - greater-than
<=                          - less-than-equal
>=                          - greater-than-equal
"car = 3"                   - create variable and assign value. in this case we assign int
%s                          - String (converts any Python object using str()); take var on the right and put it in to replace the %s with its value
%r                          - String (converts any Python object using repr()).
$d                          - Signed integer decimal
round()                     - method which is rounding numbers to whole number
"word"                      - string
'word'                      - string
True / False                - boolean
\n                          - new line
\                           - escape character
input()                     - returns the exact string
raw_input()                 - doesn't exit in python 3.x
int()                       - converts to int
str()                       - converts to string
"%s %s" % (var1, var2)      - when there is more than one argument use ->
modules                     - allows logically organize your code. it's a python object with arbitrarily named attributes
                            that you can bind and reference. Can include defined functions, classes and variables or
                            runnable code
import                      - you can use any python source file as a module by executing an import statement in some
                            other Python source file
from...import               - lets import specific attributes from a module into the current namespace
from...import*              - import all names from a module into the current namespace
argv (from sys)             - argument variable. this variable hold the arguments you pass to your Python scritp when
                            you run it
open()                      - open a file
close()                     - closes the file. Like "File->Save.." in your editor
read()                      - reads the content of your file. You can assign the results to a variable
readline()                  - reads just one line of a text
truncate()                  - epties the file. watch out if you care about the file
seek()                      -
write('stuff')              - writes "stuff" to the file
open(fname, 'w'/'r'/'a'):
"w"                         - truncate file to zero length or creae text file for writing
"r"                         - open text file for reading
"a"                         - open for writing. the file is created if it doesn't exist
echo                        - display
cat                         - display file container
len()                       - length of variable's value
def                         - for "define" function
(args*)                     - take all arguments to the function and then put them in args as a list
a function                  - piece of code that is called by name. It can be passed data to operate on and can
                            optionally return data. All data that is passed to a function is explicitly passed.
a method                    - is a piece of code that is called by name that is associated with an object. in most cases
                            it's identical to a function except two key differences:
                            1. A method is implicitly passed the object on which it was called.
                            2. A method is able to operate on data that is contained within the class (remembering that
                            an object is an instance of a class - the class is the definition, the object is an instance
                            of that data)
t = ()                      - tuple, immutable
r = []                      - list
d = {"key": "value"}        - dictionary
parameter                   - is a variable in a menthod definition / in the declaration od function.
argument                    - when a method is called, the arguments are the data you pass into tha method's parameters.
                            argument is the actual value of this variable that gets passed to function.


some practise examples:


name = "Kate"
number = 32
print("Her name is %s and her age is %d") % (name, age)     =>      Her name is Kate and her age is 32


test = "some var"
print("This is test for %s") % test     =>      This is test for some var


someFunction(20+30, 40-10)
someFunction(var1 + 10, var2 - 20)
someFunction(var1, var2)
someFunction(29, 67)