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
;>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
A bit of confusion about the split (string regex) method for string classes in Java
This class is described in the JDK Chinese API as follows:
Public string[] split(String regex)
Splits this string according to the match of the given regular expression.
The method acts as if the two-parameter split method is invoked using the given expression and the constraint parameter 0来. Therefore, the trailing empty st
C # Regular Expression Regex class usage,
I. C # Regular Expression symbol Mode
Character
Description
\
Escape Character, escape a character with special functions into a common character, or vice versa
^
Match the start position of the input string
$
End position of matching input string
*
Matches the previous zero or multiple subexpressions.
+
Match the previous subexpression o
The ExtJS regex's validation attributes are in two cases, one is a red prompt box, and the other is a comment-like message that appears on the Tip box, but adds Ext.QuickTips.init () when the page is loaded, and the prompt box is displayed correctly.
Special Note: After the attribute regex to use/^ here Gazheng then $/the above regular expression wrapping up otherwise will report "the missing object";
Copy Code code as follows:
{
X
If you are familiar with SED, awk, grep, or VI in Linux, the concept of regular expressions is certainly not unfamiliar. Because it can greatly simplify the complexity of processing strings, it has been applied in many Linux utilities. Do not think that regular expressions are only patents for Perl, Python, Bash, and other scripting languages. As a C language programmer, users can also use regular expressions in their own programs.Standard C and C ++ do not support regular expressions, but some
The content source of this page is from Internet, which doesn't represent Alibaba Cloud's opinion;
products and services mentioned on that page don't have any relationship with Alibaba Cloud. If the
content of the page makes you feel confusing, please write us an email, we will handle the problem
within 5 days after receiving your email.
If you find any instances of plagiarism from the community, please send an email to:
info-contact@alibabacloud.com
and provide relevant evidence. A staff member will contact you within 5 working days.