Python Study Notes (for your own use)

Number = 23; # define variables
Guess = 22;
If number = guess: # If judgment, note: no less
Print 'yse'; # note that indentation in python can be used only when it is included.
Elif number> guess: # note that it is not else if but Elif
Print 'Big ';
Else:
Print 'no ';
Run = true;
I = 0;
While I> 3: # While loop also note:
Print "loop ";
Print I;
I = I + 1;
If I = 5:
Run = false;
Else: # Use the running statement if the condition is not met
Print "Not while! ";
For I in range (): # For Loop range indicates that the period from 1 to 5 ends.
Print I;
# Break; # break ends
Continue; # Skip this loop
Else: # statements executed when the loop ends
Print "end ";
Def name (): # Function Definition
Print "Hello! ";
# Function end # no end
Name (); # function usage
X = 50;

# Def echo (x ):
# Print X;
# X = 2; # valid in the local Variable Function
# Return X;
# Echo (X );

Def echo ():
Global X # Use global variables
Print X;
X = 2;
Return X;
Echo ();
Print echo. _ Doc __, X; # use to output multiple variables, separated
Def null ():
'''Asdfasdfsdfasdf # function annotation, which I understand in this way
Adfadfasdfasdfasdfa ''' # End of comment. The content in the middle of ''' can be divided into multiple lines '''
Pass; # indicates that the function does not have a statement
Print null (); # output none if the function is null
# Print none. _ Doc __; # comment on the output function (which I understand)

######################################## ##########
Import sys; # use the system's SYS module
Print 'the command line arguments are :'
For I in SYS. argv: # Output System Parameters
Print I

Print '/n/nthe pythonpath is', SYS. Path, '/N' # output environment variables in the system
# Note that it is best to use the PyC file name for character encoding in the module to speed up loading and compile part of the code first.
Print _ name __; # Module name, which is generally used when determining whether it is the main module. The name of the main module is _ main __
######################################## ##########

Raw_input ('input: '); # receives data from the screen and displays input in the output. If it is accepted directly, raw_input can be used.

##############################
# Use of Classes
Class person: # declare the class name
Pop = "123"; # define the variables in the class as public
Name = '';
# Pass # An empty Block
Def _ init _ (self, name): # constructor. The method name is fixed. Self is required for input, required, followed by Parameters
Self. Name = Name;
Def sayhi (Self): # define a method
Print "woea:", self. Name;
Def echopop (Self ):
Print self. Pop;
Self. Pop = 'Come on baby ';
Print self. Pop;
Def _ del _ (Self): # destructor with fixed method names
Pass;

Class pchild (person): # inherit the person class
Def _ init _ (Self ):
Person. _ init _ (self, "sanshi"); # Use the parent class Method
Def _ del _ (Self ):
Pass
Def saychild (Self ):
Print "Child:", self. Name;
##############################

Import cpickle as P # introduce the package, which is written in C language and fast
# Import pickle as P

Shoplistfile = 'shoplist. data' # file name
# The name of the file where we will store the object

Shoplist = ['apple', 'mango', 'carrot']

# Write to the file
F = file (shoplistfile, 'w') # open the file
P. Dump (shoplist, f) # serialize the file and write it to the media. We write the file.
F. Close ()

Del shoplist # delete a list

F = file (shoplistfile)
Storedlist = P. Load (f) # Read serialized data from the file
Print storedlist
######################################## ##########
Exception Mechanism

Try:
Test code
Raise:
Throw an exception
Except t:
Capture Exception Handling
Else:
No exception
-------------------------------------------------------------
Try:
Test code
Finally:
Execute if any exceptions exist.

######################################## ############
There are a lot of other things, but I didn't take notes anymore.
Note that two packages, one sys and one OS, have completed a lot of work.