rp cookbook

not define its own Equals method, it inherits the Equals method of the object class, and the implementation code for the Equals method of the object class is as follows:Boolean equals (Obejct o) {This==o;}This means that if a class does not define its own Equals method, its default Equals method (inherited from the object class) is using the = = operator, and whether the object pointed to by the two variables is the same object, using equals and using = = will get the same result. If the compar

Bash CookBook (1)-basics, bashcookbook Bash was written by brian Fox in January 10, 1988 out of Richard Stallman's suggestion. 1. Run the template: Interactive Login shell, bash reads and executes/etc/profile after login. Then read ~ /. Bash_profile ,~ /. Bash_login ,~ /. Profile, the first executable is found to be executed. When you log out, it will read and execute ~ /. Bash_logout. Interactive non-login startup will read and execute ~ /. B

Page elementsUse the Text-align property to center the text in block-level elements. When Margin-left and Margin-right are set to auto, the element is centered relative to the parent element. However, some of the newer browsers that are popular today are not able to render this appearance correctly, such as IE5 and Netscape Navigator. If you use the th element in an HTML table, the contents of the cell are centered by default. On the basis of horizontal centering, you can center vertically and n

first list (such as L[B1] 's head), as H.2 if H does not appear at the end of the other list, output it and remove it from all lists, then go back to step 1; otherwise, take the head of the next list as H and proceed with the step.3 Repeat the above steps until the list is empty, or you can no longer find out which elements to output. If this is the case, then the algorithm ends; if it is the latter case, it means that the inheritance relationship cannot be built, and Python throws an exception

1. Tuple unpacking and decompression sequence assignment　　Any sequence (or an iterative object) can be extracted and assigned to multiple variables by a simple assignment statement. The only prerequisite is that the number of variables must be the same as the number of elements in the sequence.　　1. Parallel Assignment:>>> x = (1, 2>>> A, b = x #>>> a1>>> b 22. Use the * operator to disassemble an iterative object as a function parameter:>>> Divmod (8) # 20 for the remainder of 8, 2 * 8 + 4

causes reference count +1: Objects are created, such as N=1 object is referenced, such as N1=n The object is passed into a function as a parameter, for example, func (n) Object as an element, stored in a container, such as LIST1=[N,N1] Case that causes reference count-1 The alias of the object is explicitly destroyed, for example del a The alias of the object is assigned a new object, such as a=2 An object leaves its scope, such as the local variable i

Test--mockito for Spring boot application Initializing the database and importing data Using the in-memory database in a test Analog db with Mockito Using the Spock framework in the Spring boot project VI. Application Packaging and Deployment Packaging and deployment of Spring boot applications VII. application monitoring and data visualization Health monitoring for Spring boot applications Use of Spring Boot admin Monitor spring boot

input iteration type, so the length of the Cartesian product list is equal to the product of the length of the input variable.1. Calculating Cartesian product using list derivation>>> colors = ['Black',' White'] >>> sizes = ['S','M','L'] >>> tshirts = [(color, size) forColorinchColors forSizeinchSizes]>>> Tshirts[('Black','S'), ('Black','M'), ('Black','L'), (' White','S'), (' White','M'), (' White','L')] >>> forColorinchcolors: # Use for loop is the same effect ... forSizeinchSizes: ...Print((c

the number of days in different months. DateTime cannot process months.>>> fromDateutil.relativedeltaImportRelativedelta>>> A = DateTime (2017, 9, 8)>>> A + relativedelta (Months=1) Datetime.datetime (2017, 10, 8, 0, 0)>>> A + relativedelta (months=4) Datetime.datetime (2018, 1, 8, 0, 0)>>> B = DateTime (2017, 11, 11)>>> d = B-a>>>Ddatetime.timedelta (64)>>> d =Relativedelta (b, a)>>>Drelativedelta (Months=+2, Days=+3)>>>d.months2>>>d.days33. Convert string to time, use Datetime.strptime (), co

file)Modify PermissionsModify file permissions: chmod 600/root/.ssh/authorized_keysModify directory Permissions: chmod 700/root/.sshTo remove a firewall rule:Iptables-fService Iptables SaveTurn SELinux off and temporarily shut down with Setentforce 0Permanently closed as: Vi/etc/selinux/config selinux=disabled.Finally, upload the private key to puttySsh->auth650) this.width=650; "src="/e/u261/themes/default/images/spacer.gif "style=" Background:url ("/e/u261/lang/zh-cn/ Images/localimage.png ")

;>Print_chars.Argtypes=(cTYPES.C_char_p,)>>> print_chars (b " Hello World ' ) 48 6c 6c 6f (6f) 6c 64>>> print_chars (b ' hello\x00 World ' 48 6c 6c 6f>>> print_chars ' Hello World ' ) traceback (most recent call last): File "1, argument 1: >>> If you want to pass a string instead of a byte, you need to perform a manual UTF-8 encoding first. For example:Print_chars(' Hello World '). Encode(' utf-8 '))6c 6c 6f, 6f 6c>>> For other extension tools (such as Swig, Cython),When you use them

to use the extension code to perform the correct conversion, as follows:Static Pyobject *py_print_chars (Pyobject *self, Pyobject *args) { char *s = 0; int Len; if (! Pyarg_parsetuple (args, "es#", "Encoding-name", s, len)) { return NULL; } Print_chars (S, Len); Pymem_free (s); Py_return_none;}Finally, if you want to work directly with Unicode strings, here is an example that shows the underlying operation access:Static Pyobject *py_print_wchars (Pyobject *self, Pyobject *args) { p

: resourcewarning:unclosed file mode= ' R ' encoding= ' UTF-8 ' >>>> By default, not all warning messages will appear. -w option to control the output of the warning message. -wall All warning messages will be output, -wignore Ignore all warnings, -werror Convert warnings to exceptions. Another option, you can also use warnings.simplefilter () function control output. always parameters will cause all warning messages to appear " Ignore Ignore all warnings, error

Label:The fifth Chapter Metadata query query database itself Information table structure index, etc.5.1 Querying all table information under the test libraryMysql from ' Test ';ORACLESelect from where ' Test ';5.2 Querying the information for columns in a tableMysqlSELECT * from WHERE = ' Test ' and = ' Student ';ORACLESelect * from where = ' Test ' and = ' Student ';5.3 List Indexes of tablesMysqlIndex from EMP;ORACLESelect from where = ' EMP ' and = ' Test ';5.4 Listing table constrain

NULL.To resolve this problem, you can use is to determine null:1 mysql>Selectfromwherenot=1or =2or=3orisnull) \g5. Left JoinA a LEFT outer join b bReturns all rows in a, match in B returns, or null if no match6. N-1 RulesIf the FROM clause has n tables, the minimum number of n-1 joins is required to avoid producing a Cartesian product7. Full OUTER JOIN onReturns the missing rows from two tables and all matching rows8. Use null for calculations and comparisonsUse the COALESCE function to conver

() functionb, use the Format function date_format () or Time_format () and a specific format string to get a date or time value to decompose the required partC, treat a time or date as a string, and then use the left () or mid () function to get the desired portion from it.Extract () function to decompose a date or time valueUse the Format function to decompose a date or time value:Benefit: Display the resulting decomposition results in a user-specified formatUse a string to decompose time or d

Python cookbook (data structure and algorithm) dictionary-related computing example, pythoncookbook This example describes the computation problems related to the Python cookbook (data structure and algorithm) dictionary. We will share this with you for your reference. The details are as follows: Problem:Perform Various calculations (such as minimum, maximum, and sorting) on the data in the dictionary ). So

Online see about the use of pandas, although practiced a lot, but still some can not remember very clearly. So it was written down.Chapter1 is talking about reading a CSV file. The following code:1 #%%2 ImportPandas as PD3 ImportNumPy as NP4 ImportMatplotlib.pyplot as Plt5 #Make the graphs a bit prettier6Pd.set_option ('Display.mpl_style','default')7plt.rcparams['figure.figsize'] = (15,5)8 9 #%%TenBROKEN_DF = Pd.read_csv ('C:\Users\rui\Desktop\pandas-cookboo