Python Basics---Module

 Import day5.lib.commands           # Importing module r=day5.lib.commands.testmodule () Print (R)  from  Import logout as M1_logout   # function for importing a module r=m1_logout ()  Import  sysprint(SYS.ARGV)

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# Install third-party module methods:
#1, pip command installation
# If the report is not an internal or external command, it is an environment variable problem, find the Python installation directory, use the absolute path to execute the PIP command
#C: \users\zhoufeng\appdata\local\programs\python\python35\scripts\pip Install requests

#2, source installation


Two, JSON and pickle module
JSON modules are used for converting strings to Python basic data types (lists, tuples, dictionaries, and so on), because strings are data types for each language, so JSON is used to pass data between languages
Pickle module for serialization and deserialization of any Python object

ImportJSON##json有四种方法: Dumps dump loads loaddic={'K1':'v1'}Print(Dic,type (DIC)) result=json.dumps (DIC)#json.dumps () converts a Python base data type to a stringPrint(Result,type (Result)) S1='{"K1": 123}'DiC=json.loads (S1)#json.loads () converts a dictionary-form string into a Python dictionary, and a list-form string to a python listPrint(Dic,type (DIC)) Li=[11,22,33]json.dump (Li,open ('DB','W'))#dumps directly in memory convert dump can be used to write filesLi=json.load (Open ('DB','R'))#loads the conversion directly in memory, load can be used to read the filePrint(Type (li), Li) LST="[' Alex ', ' Zhoufeng ']"ret=json.loads (LST)Print(Type (ret))##########################################ImportPickleli=[11,22,33]r=Pickle.dumps (LI)Print(r) Result=pickle.loads (R)Print(Result) Li=[11,22,33]pickle.dump (Li,open ('DB','WB'))#the difference between JSON and pickle:#There are four ways to do both JSON and pickle#JSON is more suitable for cross-language but only for basic data types (dictionaries, lists, tuples)#Pickle only for Python but can be used for all types of Python serialization

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Import Pickleli= (11,22,33) R=Pickle.dumps (li)print(r)#  Pickle.dumps Usage: string =pickle.dumps (Sequence)li_new=pickle.loads (r)print(li_new)  #pickle.loads usage: sequence =pickle.loads (String)

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ImportPickleclassTeacher:def __init__(self,name,age,asset,coursename): Self.name=name Self.age=Age Self.asset=Asset Self.coursename=coursenameteacherlist=[]teacher1=teacher ('Zhoufeng', 18, 10,'Shuxue') Teacher2=teacher ('Malulu', 18, 10,'Zhongwen') Teacher3=teacher ('Zhoufang', 19, 20,'Yingyu') teacherlist.append (teacher1) teacherlist.append (teacher2) teacherlist.append (Teacher3) with open ('Test1.txt','WB') as File_obj1:#note file name with suffixpickle.dump (teacherlist,file_obj1)#pickle.dump usage: pickle.dump (sequence, file object)With Open ('Test1.txt','RB') as File_obj2:li=pickle.load (FILE_OBJ2)#pickle.load usage: Sequence =pickle.load (File object)Print(LI)

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Three, requests module

# Import Requests # Import JSON # response=requests.get (' http://wthrcdn.etouch.cn/weather_mini?city= Beijing ') # response.encoding= ' Utf-8 ' # print (Response.text) # dic=json.loads (Response.text) # Print (Type (DIC))

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Iv. modules related to system operation




Five. String module

Translate () and Maketrans ()
Maketrans ("Abe", "Abe")  a-->a  b-->b  e-->e     generate conversion Relationship table
Translate (ARG1,ARG2)   Arg1 is the conversion relationship table generated by the Maketrans function, arg2 can not, representing the characters that need to be removed

Example 1: ' A ' and ' T ' correspond to   ' C ' and ' G ' corresponding to   each other to convert    input "AATTC"   output "Ttaag"

Import string         #python3中不需要导入def Dna_strand (DNA):    return Dna.translate (String.maketrans ("ATCG", "TAGC"))

Example 2: Remove ' 123 ' and then ' a '--' a ' ' B '--' B ' C '--' C '

>>> Import String                  >>> T=string.maketrans (' abc ', ' abc ') >>> ' abc123 '. Translate (t, ' 123 ') )    ' ABC '

Vi.. Collections Module

Counter ()

Counts the elements in a sequence and returns it as a dictionary, and can also set the difference between sets

>>> fromCollectionsImportCounter>>> string1="Aaabb">>>PrintCounter (string1) Counter ({'a': 3,'b': 2})>>> >>> string2="BBCCC">>>PrintCounter (string2) Counter ({'C': 3,'b': 2})>>> >>>PrintCounter (string1)-counter (string2)#returns the difference between string1 and string2 (part of string1 but not in string2)Counter ({'a': 3})>>> >>> string3="AABB">>>PrintCounter (string3) Counter ({'a': 2,'b': 2})>>>PrintCounter (string1)-counter (string3)#returns the difference between string1 and string3Counter ({'a': 1})

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Python Basics---Module