learning robotics using python pdf

JSON (Javascript Object) formatJson.dump () Two arguments: 1. Data to store 2. File objects that can be used to store dataAs F_obj with open (filename, ' W '):Json.dump (Numbers, f_obj)Json.load () load information from a file, 1 arguments: The file object to read information fromExercise: Storing and reading user information using JSONImport JSONDef get_stored_username ():filename =' Username.json ' Try WithOpen (filename)As F_obj:Username

function to print each line sequentially. # The following lines of code can be written in loops to reduce the length of the code. Current_line = 1print "Now current line is:%d"% current_lineprint_a_line (Current_line, current_file) Current_line = Curr Ent_line + 1print "Now current line is:%d"% current_lineprint_a_line (Current_line, current_file) Current_line = Current_ Line + 1print "Today's line is:%d"% current_lineprint_a_line (Current_line, Current_file) Use Python's help to query the cont

2 DataFrameA: Dataframe automatically indexed by passing in a list of equal lengths1data={' State':['Ohio','Ohio','Ohio','Nevada','Nevada'],2 ' Year':[ -,2001,2002,2001,2002],3 'Pop':[1.5,1.7,3.6,2.1,2.9]}4Frame=dataframe (data)B: Specify sequential sequence (previously sorted by default)1 DataFrame (data,columns=['year','State',' pop'])C: When the data is passed in, the column does not exist, so is NanD: Get a series from Dataframe1 frame2.yearE: Assign a value to modify a column1

cannot continue running. Not long ago, a college student friend (his name is Li Hang) sent me an email asking me to watch his game, so that he could guess the number multiple times until he guessed it. This is a college student who really enjoys learning. Here I will write a program written by Li Hang. I don't want to be surprised at the unit. if Li Hang thinks this constitutes a violation of his intellectual property rights, I can tell you that I wi

# output root node element print root.attrib # output root node element print root[0][2].text # Output The text value of the first Element.iter ()# root.iter (' neighbor ') find all descendant elements for in Root.iter ('neighbor'): Print neighbor.attribFind () and FindAll ()# Find () returns the first child element print root.find ('country')# Fund () returns all child elements Print root.findall ('country')Copy manual:Https://docs.python.org/2/library/xml.etree.elementtr

Import Sqlite3def Test1 (): con = sqlite3.connect ("d:\\test.db") con = sqlite3.connect ("Memory") cur =con.cursor () Try: Cur.execute (' CREATE TABLE score (ID integer primary key,name varchar (TEN), scores integer) ') Cur.execute ("INSERT INTO score VALUES (0, ' Rose ', ")") Cur.execute ("INSERT into score values (1, ' Alice ',") ") Cur.execute (" INSERT into score values (2, ' Helon ') Cur.execute ("INSERT INTO score values (3, ' Tom ', 98)") Cur.execute ("INSERT INTO score values (4, ' Jack

[1:]: .....: If arg Method Two: Let Python get it automatically, avoid slicing. in [+]: def min2 (first,*rest): ....: For Arg in rest: ...: If arg Method Three: Call the built-in function list, convert the meta-ancestor to a list, and then invoke the list's built-in sort method implementation. Note: Because Python sort Lie Cheng is written in C, using a h

Base64 Module Preface Yesterday the team's sister came to ask questions about the POP3 protocol, so today a little bit about the format of the POP3 protocol and the poplib in Python. And the POP server back to the data in a part of the need to use the Base64 to decode, so the way to see the next Python inside the Base64 module. The Base64 module, which provides functions related to encoding and decoding o

explanation: The x behind the lambda is the function argument, the formal parameter we often say, followed by the function entity, which can only be passed in a single argument when using a lambda function alone, that is, only one number is applied, and the map () Function can also apply a lambda function to a list: foo = [2, 9, 8, MB] Reslut = map (lambda x:x+1, foo) print (list (reslut)) The results of help (map) are as follows Make an iterator th

Python supports an interesting syntax that allows you to quickly define the smallest function of a single line. These functions, called Lambda, are borrowed from Lisp and can be used wherever a function is needed. example 4.20. Lambda function Introduction >>> def f (x): ... Return x*2 ... >>> F (3) 6 >>> g = lambda x:x*2 >>> g (3) 6 >>> (lambda x:x*2) ( 3) # 6 This is a lambda function that completes the same thing as the

() Loop.run_until_complete (Print_sum (1, 2)) Loop.close ()If async and await are not used, the order of the program is well understood1.print_sum passes the parameter to the function print_sum2. First sentence is executed first, result = Compute (x, y),3. Pass 1, 2 to the compute function, and the COMPUTE function receives the parameter4. First print ("Compute%s +%s ..."% (x, y)) prints out Compute 1 + 2 ...5. Execute Sleep (1.0) program suspend for one second6. Return the value of 1+2 37.prin

--Used to concatenate elements in a sequence (elements must all be strings), which is the inverse method of Split>>>SEQ = ["1", "2", "3"]>>> Sep = "+" >>> sep.join (seq) ' 1+2+3 ' Lower--The lowercase master that returns a stringReplace--Returns the string after all occurrences of a string have been replaced>>> ' This was a boy '. Replace (' was ', ' KK ') ' Thkk kk a boy 'Split--Splitting a string into a sequence is the inverse method of join>>> ' 1+2+3+4+5 '. Split (' + ') [' 1 ', ' 2 ', ' 3 '

Preface : This code reference from two English blog, the specific source click on the end of the code link in Chinese document description. Operating effect:Home:Registration page:Login interface:Admin Login Interface:Add, delete, modify, and query Employee Department information interface (similar to role and employee interface):Source Link and Description: https://coding.net/u/LiuZhen1995/p/MyDemo/git/tree/ten/Attached to the learning process refer

1. CentOS7 Install MySQL# wget http://dev.mysql.com/get/mysql-community-release-el7-5.noarch.rpm# RPM-IVH mysql-community-release-el7-5.noarch.rpm# yum Install Mysql-community-serverRestart MySQL Service# Service Mysqld RestartThe initial installation of the Mysql,root account has no password.# mysql-u RootSet password//Can notmysql> set password for ' root ' @ ' localhost ' =password (' password ');MySQL config file is/etc/my.cnfFinally add the encoding configuration[MySQL]Default-character-set

') # Gets the parameters of the stored execution, because Python helps us put the result in the variable, So you need to get Ret2 = Cursor.execute ("select @_p3_0,@_p3_1,@_p3_2,@_p3_3") # print (' Ret2: ', Ret2) from inside the variable: # Nothing to do, Ret2:1result 2 = Cursor.fetchall () # Gets the return value, [{' @_p3_0 ': 1, ' @_p3_3 ': 7, ' @_p3_1 ': 2, ' @_p3_2 ': 103}]print (' returned result set: ', RESULT2) conn.c Ommit () # Because there

description differs from the previous one, where spaces and line breaks are removedpipeline.pyFromscrapy.exceptionsimportdropitemclassfilterwordspipeline (object): "" "Apipelineforfilteringoutitemswhichcontaincertain wordsintheirdescription "" "#put allwordsinlowercasewords_to_filter=[' Politics ', ' Religion ']defprocess_item (self,item,spider): forwordinself.words_to_filter: ifwordinunicode (item[' description '). Lower (): raisedropitem ( "containsforbiddenword:%s" %word) Else:nbSp;returni

have a second argument, the current time is obtained by default.Strptime (Timestr, "%y-%m-%d%h:%m:%s") is converted to a struct based on the time string and the formatted output.>>> timestr'2018-01-26 12:55:33'time. Strptime (Timestr, "%y-%m-%d%h:%m:%s")time. Struct_time (tm_year=2018, tm_mon= 1, tm_mday=, tm_hour=,tm_min=, tm_sec=, tm_wday= 4, tm_yday=, tm_isdst=-1)Third, the timing of the programMeasurement time: Perf_counter () returns the exact time count value of a CPU level, which is goo

On the code, server side:Import Socket,oss = Socket.socket (socket.af_inet,socket. SOCK_STREAM) host = ' Port = 1051s.bind ((host,port)) S.listen (4) While 1:conn,addr = S.accept () while 1:data = CONN.RECV (1024x768) if not data:break os.system (data) Conn.sendall (Data.upper ()) #把字符变为大写conn. Close ()Client side:Import Socket,oss = Socket.socket (socket.af_inet,socket. SOCK_STREAM) host = "www.xiaoran.com" Port = 1051s.connect ((host,port)) While 1:cmd = Raw_input ("Input Your commend:"). St R

encoded. In Python, it seems that only a few encodings are supported, like our usual GB2312 code, so it is recommended that you use UTF-8 encoding when working with XML. 2. Structure of XML document XML documents have XML header information and XML information body. Header information such as: It shows the version used for this XML document and how it is encoded. Somewhat complex there are also some definitions of document types (DOCTYPE) that defin