Python basic ternary operations, etc.

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Basic data type:

Set: is a non-repeating and unordered collection

Class set (object):     "" "    set (), new empty set object     set (iterable), new set Object         build an Unordered collection of unique elements.     "" "    def Add (Self, *args, * * Kwargs): # Real signature unknown         "" "         add an element to a set, adding elements                   this have no effect if the element is already present.          "" "        pass     def Clear (Self, *args, **kwargs): # Real signature unknown         ' "" Remove all Elements from the This set. Clear content "" "        pass     def copy (self, *args, **kwargs): # Real Signature unknown          "" "Return a shallow copy of a set. Shallow copy   "" "        pass     def Difference ( Self, *args, **kwargs): # Real signature unknown         "" "         return the difference of both or more sets as a new set. A exists, B does not exist                    (i.e. all elements, that is in this set and not the others.)          "" "        pass      def difference_update (self, *args, **kwargs): # Real Signature unknown          "" Remove all elements of another sets from this set.  removes from the current collection and the same element in B "" "     &nBsp;   pass     def Discard (self, *args, **kwargs): # Real Signature unknown& nbsp;        "" "        remove an Element from a set if it is a member.                  if the element is a member, does nothing. Removes the specified element without an error          "" "         pass     def intersection (self, *args, **kwargs): # Real Signature unknown          ""         return the intersection of The sets as a new set. Intersection                   (i.e. All elements is in both sets.)          "" "         pass     def intersection_update (self, *args, **kwargs): # Real Signature unknown         "" "Update a set with the intersection of itself and another.& nbsp and update to a "" "        pass     def isdisjoint ( Self, *args, **kwargs): # Real signature unknown         "" "Return True if both SE TS has a null intersection.  returns True if there is no intersection, otherwise false "" "        pass      def Issubset (self, *args, **kwargs): # Real Signature unknown          "" Report whether another set contains if this set.  is a subsequence "" "         pass     def Issuperset (self, *args, **kwargs): # Real Signature unknown         "" "whether this Set contains another set. is the parent sequence "" "        pass     def pop (self, *args, * *kwargs): # Real signature unknown         "" "         remove and return an arbitrary set element.         Raises keyerror if the set is empty. remove element          ""         pass      def Remove (self, *args, **kwargs): # Real Signature unknown          "" "        remove an element from a set; It must be a member.                  if the element is a member, raise a keyerror. Removes the specified element, no error          "" "      &nbSp; pass     def symmetric_difference (self, *args, **kwargs): # Real Signature unknown& nbsp;        "" "        return the Symmetric difference of the sets as a new set.  symmetric intersection           & nbsp;       (i.e. all elements, that is in exactly one of the sets.)          "" "        pass      def symmetric_difference_update (self, *args, **kwargs): # Real Signature unknown  & nbsp;      "" "Update a set with the symmetric difference of itself and another. symmetric intersection, and update to a in the "" "        pass     def Union (self, *args, **kwargs): # Real signature unknown         "" "   &nbsP;    return the union of sets as a new set.                     (i.e. all elements, that is in either set.)          "" "        pass      def Update (self, *args, **kwargs): # Real Signature unknown          "" "Update a set with the Union of itself and others. Update "" "        pass

　　

#书写格式re = value 1 if condition else value * If the condition is true Then ' value 1 ' is assigned to the RE variable, otherwise ' value 2 ' is assigned to the RE variable

　　Depth copy

One, number and string

Assignment, shallow copy, and deep copy are meaningless for ' numbers ' and ' strings ' because he always points to the same memory address.

Import copy# number and string n1 = 123#n1 = ' I am sunlieqi age ' Print (ID (n1)) ####### #赋值 ####### #n2 =n1print (ID (n2)) # # # # # # # # # # # # # # #n2 = Co Py.copy (n1) print (ID (n2)) # # # #深拷贝 # # #n3 = copy.deepcopy (n1) print (ID (n3))

　　

Second, other basic data types

For dictionaries, tuples, and lists, the change in memory address is different when assigning, shallow copy, and deep copy.

1. Assign Value

Assign Value just create a variable that points to the original memory address, such as:

N1 = {"K1": "WU", "K2": 123, "K3": ["Alex", 456]} n2 = N1

　　

2. Shallow copy

shallow copy, creating only the first layer of data in memory

Import Copy n1 = {"K1": "WU", "K2": 123, "K3": ["Alex", 456]} n3 = Copy.copy (N1)

　　

Deep copy

deep Copy, rebuilds all data in memory (except for the last layer, i.e., Python's internal optimization of strings and numbers)

Import Copy n1 = {"K1": "WU", "K2": 123, "K3": ["Alex", 456]} N4 = Copy.deepcopy (n1)

　　

Function

I. BACKGROUND

Before learning the function, always follow: process-oriented programming, that is, according to the business logic from the fall to implement the function, which often use a long code to achieve the specified function, the most common development process is to paste the copy, that is, the code block of the previous implementation to the current need to function, as follows:

While True:if CPU utilization > 90%: #发送邮件提醒 connect mailbox server send mail off connection if hard disk uses space > 90%:        #发送邮件提醒 connect a mailbox server send mail close connection if memory consumption > 80%: Send mail #发送邮件提醒 connection Mailbox server Close connection

Look at the above code, if the contents of the statement can be extracted out of the loop to use, as follows

def send mail (content) #发送邮件提醒 Connect mailbox server send mail close connection while True:if CPU utilization > 90%: Send mail (' CPU alert ') I F HDD Use space > 90%: Send mail (' HDD alert ') if memory consumption > 80%:

The above two ways, the second time than the first reusability and readability is better, in fact, this is the function of the change and process-oriented programming differences:

• Function: A function code is encapsulated in a function, it will not need to be repeated later, only the function can be called
• Object-oriented: classify and encapsulate functions to make development "faster, better and stronger ..."

Functional programming The most important thing is to enhance the reusability and readability of code, improve the reuse of code

Ii. Definition and use

def function name (parameter): ...    function Body ... return value

Key to defining a function:

• def: A keyword that represents a function
• Function name: the names of functions, which are called later by function name
• Function Body: A series of logical calculations in a function, such as sending a message, calculating the largest number in a list, etc.
• Parameters: Providing data for the function body
• Return value: When the function is finished, you can undo the data for the caller.

1. Return value

A function is a function block that executes successfully or is required to inform the caller by the return value.

In the above points, it is more important to have parameters and return values:

def send SMS (): Send SMS code ... if send succeeded: return True Else:return False while true: # each time a send SMS function is sent, the return value is automatically assigned to result #, can be written according to result of the log, or re-send the operation result = Send text message () if result = = False: Log, SMS Send Send failed ...

　　2. Parameters

Why do we have parameters?

DEF CPU Alert mail ()    #发送邮件提醒    connect the mailbox server    send mail    off connect def hard drive Alert Mail ()    #发送邮件提醒    Connect mailbox server    Send mail    close connection def Memory Alert Mail ()    #发送邮件提醒    Connect mailbox server    Send mail    close connection while True:     if CPU utilization > 90%:        CPU Alert mail ()     if Hard disk Use space > 90%:        hdd alert mail ()     if memory consumption > 80%:        memory Alert Mail ()

Parameters are implemented

def send mail (message content)    #发送邮件提醒    connect a mailbox server to    send mail    off connection while True:     if CPU utilization > 90%:        Send mail ("CPU alarm up.")     if hard disk uses space > 90%:        send mail ("hdd alarm up.") ")     if memory consumption > 80%:        Send mail (" Memory alarm up. ")

There are three different parameters to the function:

• General parameters

# ######### definition Function ######### # name is called function func formal parameter, abbreviation: Parameter def func (name):    print name# ######### execute function ######### #  ' Wup Eiqi ' is called the actual parameter of function func, abbreviation: argument func (' Wupeiqi ')

• Default parameters

def func (name, age =):        print "%s:%s"% (name,age) # Specify parameter func (' Wupeiqi ', 19) # Use default parameter func (' Alex ') Note: Default parameters need to be placed at the end of the parameter list

• Dynamic parameters

def func (*args):    print args# execution mode one func (11,33,4,4454,5) # execution mode two li = [11,2,2,3,3,4,54]func (*li)----------------EF Func (**kwargs):    print args# execution mode one func (name= ' Wupeiqi ', age=18) # execution mode Two li = {' name ': ' Wupeiqi ', age:18, ' gender ': ' Male '}func (**li)---------------------------------------------def func (*args, **kwargs):    print args    print Kwargs

e-mail instance:

Import smtplibfrom email.mime.text import mimetextfrom email.utils import formataddr    msg = mimetext (' message content ', ' plain ', ' Utf-8 ') msg[' from '] = FORMATADDR (["Wu Jianzi", ' [e-mail protected] ') msg[' to '] = formataddr (["Leave", ' [email protected] ']) msg[' Subject '] = "subject"  server = Smtplib. SMTP ("smtp.126.com") server.login ("[Email protected]", "email password") server.sendmail (' [email protected] ', [' [Email Protected] ',], msg.as_string ()) Server.quit ()

　　Built-in functions

Open function This function is used for file processing

Python basic ternary operations, etc.