One, Module 1. module
(1) Definition: A. py file is a module
(2) Reason: In order to prevent the program code getting longer, the functions are grouped into different folders.
(3) Advantages: Improve the maintainability of the code, the module can be written to be referenced by others, you can also refer to other modules; You can avoid conflicting variable names and function names
(4) Module type: A total of three kinds of ①python standard library; ② third-party module; ③ Application custom Module
2. Module Import method
The essence of module import: by Sys.path find the function to import and execute the script, the (1) method loads the variable name into the variable space, (2) loads the variable name in
(1) Import statement
Import Timetime.sleep (2) Print ("OK")
View Code
(2) From...import statement
from Import = cal ($)print(res)
View Code
(3) from...import* statement
from Import *# does not recommend this method, it is possible to overwrite the function defined by itself (function is variable)res1 =cal (2,3 = sub (4,2) Print (Res1,res2)
View Code3. Package
In order to avoid the module conflict, according to the directory to organize the module, this directory will be delivered, the package directory will have a __init__ file, which is the difference between the package and the normal folder
All modules below the package will not conflict as long as the top-level package name does not conflict
Multilayer Package Reference
from Import = cal ($)print(res)
View Code4. Test code
if __name__= ="__main__":
Two features: 1. Display "__main__" in the execution code; 2. Display the name of the file in the calling module
(1) function one: When debugging the code, add, when the module is called from another. py file, the contents of debugging are not displayed
def cal (x, y ): return (x+y) def Sub (x, y ): return (xy) if __name__= ="__main__" :print (" OK")
View Code
(2) function Two: In the execution of code, to prevent their own logic code is called by others
Second, time module 1. Timestamp
Import Time Print (Time.time ()) # Timestamp number of seconds, starting from the early 1970, the birth time of Unix
View Code2. Structured time
Import Time Print (Time.localtime ()) # local time Print (Time.gmtime ()) # UTC Time
View Code
Convert structured time to timestamp
Import Time Print (Time.mktime (Time.localtime ()))
View Code
Convert structured time to string time
Import Time Print (Time.strftime ("%y-%m-%d %x", Time.localtime ()))
View Code
3. String time
Import= time.localtime ()print(time.asctime (t))Print (Time.ctime (1124324))
View Code
Convert string time to structured time
Import Time Print (Time.strptime ("2018-5-11 21:01:26","%y-%m-%d%x"))
View Code4.time.sleep () and Time.clock ()
Time.sleep () Delays the specified time run, in seconds
The Time.clock () function returns the current CPU time in seconds calculated as a floating-point number. It is more useful than time.time () to measure the time spent on different programs. It is important to note that the meanings are different on different systems. On a UNIX system, it returns "process time", which is a floating-point number (timestamp) in seconds. In Windows, the first call returns the actual time that the process is running. The second subsequent call is the elapsed time since the first call to the present. (actually based on QueryPerformanceCounter () on WIN32, which is more accurate than milliseconds)
Import Time Print (Time.clock ()) Time.sleep (2) Print (Time.clock ())
View Code5.datetime Module
Show Current Time
Import datetime Print (Datetime.datetime.now ())
View CodeThird, random module
The random module mainly has the following functions
ImportRandomPrint(Random.random ())#randomly generate a floating-point number less than 1Print(Random.randint (1,3))#randomly generates an integer that can be taken to 3Print(Random.randrange (1,3))#randomly generates an integer that takes less than 3Print(Random.choice ([11,22,33,44]))#randomly select a number from a listPrint(Random.sample ([11,22,33,44],2))#randomly select two numbers from a listPrint(Random.uniform (1,4))#generate floating-point numbers within a specified rangeret = [1,2,3,4,5]random.shuffle (ret)#Scramble OrderPrint(ret)
View Code
Generate Verification Code
Import Random def V_code (): "" for in range (4): = Random.randint (0,9) = Chr (Random.randint (65,90)) = Str (random.choice ([Num,letter]) + = s return ret Print (V_code ())
View Code
The path of Python development--8