mongodb advanced part groupbycasewhenselectdistinctsubstr(sdf,0,6)

Mongodb advanced part: 1. Mixed use of gourp by and case when 1. Let’s look at a table. The structure of the table is (one piece of data) { “_id” : ObjectId(“57876215b522253ff42e3346”), “type” : NumberInt(0), “userId” : NumberInt(101920), “pointsNum” : NumberInt(50), “createdDate” : NumberLong(1468490260993), “lastModifiedDate” : NumberLong(1468494579572),} 2. Now we need to group and count pointsNum according to userId, and summarize them into two fields according to the different type values, so we need to implement a writing method similar to sql This is a sql writing method without verification, as long as you can understand it: select outPointsTotalNum as sum(case when type=0 then pointsNum else 0),consumePointsTotalNum as sum(case when type=1 then pointsNum else 0)from table_aaagroup by userId; 3. To achieve similar requirements in mongodb, you need to use $cond,$group $cond[aaa,bbb,ccc] is similar to case when, and the ternary operator aaa?bbb:ccc aggregate is also used in this article, and the final statement is as follows db.d_points_detail.aggregate( [ { “$group” : { “_id” : “$userId ” , “outPointsTotalNum” : { “$sum” : { “$cond” : [ { “$eq” : [ “$type” , 0]} , “$pointsNum” , 0]}},”consumePointsTotalNum” : { “$sum” : { “$cond” : [ { “$eq” : [ “$type” ,…

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Use Java simulation to implement disk array raid levels 0, 1, 3, 5, 6, 01, 10

Table of contents 1. Instructions for use 2. Overall design 3. Operation screenshots 4. Detailed design 4.1raid0 4.2raid1 4.3raid3 4.4raid5 4.5raid6 4.6raid01 4.7raid10 5. Source code 1. Instructions for use The development environment of this program is the Windows operating system Eclipse software – developed using Java language. When using, open the project file and run Main.java under the raidMain package. According to the prompts, enter the file to be written “full path of the file” and the file to be read. The entered file path indicates file reading. The saved path “contains the file name to be read” and the file can be restored. The disk “folder” used by each disk array level data is different. For example, the main disk path of raid0 is disk/raid0 and raid6 is disk/raid6. The other disk/read and disk/read are used to demonstrate the file path for writing and reading. Of course, you can also choose other files for operation. Data when the disk is damaged when raid3, 5, and 6 are not completed. Restoration: After writing, I still found that there were still big problems with the program structure. However, the changes took a lot of time and I just let it…

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Use Java simulation to implement disk array raid levels 0, 1, 3, 5, 6, 01, 10

Table of contents 1. Instructions for use 2. Overall design 3. Operation screenshots 4. Detailed design 4.1raid0 4.2raid1 4.3raid3 4.4raid5 4.5raid6 4.6raid01 4.7raid10 5. Source code 1. Instructions for use The development environment of this program is the Windows operating system Eclipse software – developed using Java language. When using, open the project file and run Main.java under the raidMain package. According to the prompts, enter the file to be written “full path of the file” and the file to be read. The entered file path indicates file reading. The saved path “contains the file name to be read” and the file can be restored. The disk “folder” used by each disk array level data is different. For example, the main disk path of raid0 is disk/raid0 and raid6 is disk/raid6. The other disk/read and disk/read are used to demonstrate the file path for writing and reading. Of course, you can also choose other files for operation. Data when the disk is damaged when raid3, 5, and 6 are not completed. Restoration: After writing, I still found that there were still big problems with the program structure. However, the changes took a lot of time and I just let it…

Write java to merge two arrays, {1,2,3,4,5}{4,5,6,7,8}

Java writes two arrays to merge, {1,2,3,4,5} {4,5,6,7,8} It is divided into two steps: 1. Connect the two arrays.2. Clear duplicate elements.import java.util.Arrays; public class Combine{ public static void main(String[] args){ int a[]={1,2,3,4,5}; int b[]={ 4,5,6,7,8}; int temp[]=new int[a.length+b.length]; //Connect two arrays for(int i=0;ijava writes to merge two arrays, {1 ,2,3,4,5} {4,5,6,7,8} &lt How to combine java string arrays into one array in java? h3> java

(Reprinted) version8.5onlysupportsJ2EE1.2,1.3,1.4,andJavaEE5,6,and7Webmodules appears when adding a project in tomcat

(Reprinted) version8.5onlysupportsJ2EE1.2,1.3,1.4,andJavaEE5,6,and7Webmodules appears when adding a project in tomcat

Go to the .setting folder of the project Edit the file org.eclipse.wst.common.project.facet.core.xml Lower the version number of this item. The above defaults to 4.0, I lowered it to 3.0. (My tomcat is 8.5 and java is 1.8)

Java5, 6, 7, 8, 9, 10, 11 new features

Reprinted from https://it18monkey.github.io java5 Generics List list=new ArrayList (); Enhanced for Loop int[] array = { 1, 2, 3, 4, 5}; for (int i : array) { System.out.println(i); } Autoboxing/Unboxing (Autoboxing/Unboxing). The eight basic types and their packaging classes can be automatically converted to each other. Enumeration (Typesafe Enums). ps: Enumeration is a good way to implement thread-safe singleton mode. enum TestEnum{ one, two; TestEnum() { } } Varargs Syntax: (type… arguments) The essence of variable parameters is still to use a Arrays store parameters, but Java hides this process. It should be noted that if a method declaration contains variable parameters, they must be placed in the last position. /** * Variable parameter test* * @param args */ public static void testVarargs(String… args) { //Essentially it is an array System.out.println( args[1]); for (String arg : args) { System.out.println(arg); } } Static Import. Use the static variables or methods in the class by importing the class (directly through the name, no need to add class name.), which simplifies code writing. //Single importimport static java.lang.Math.PI; //Batch importimport static java.lang.Math.*; ps: In past versions It can only be used by inheriting a class or implementing an interface. Annotations. Keyword @interface. //Annotations of…

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Use Java simulation to implement disk array raid levels 0, 1, 3, 5, 6, 01, 10

Table of contents 1. Instructions for use 2. Overall design 3. Operation screenshots 4. Detailed design 4.1raid0 4.2raid1 4.3raid3 4.4raid5 4.5raid6 4.6raid01 4.7raid10 5. Source code 1. Instructions for use The development environment of this program is the Windows operating system Eclipse software – developed using Java language. When using, open the project file and run Main.java under the raidMain package. According to the prompts, enter the file to be written “full path of the file” and the file to be read. The entered file path indicates file reading. The saved path “contains the file name to be read” and the file can be restored. The disk “folder” used by each disk array level data is different. For example, the main disk path of raid0 is disk/raid0 and raid6 is disk/raid6. The other disk/read and disk/read are used to demonstrate the file path for writing and reading. Of course, you can also choose other files for operation. Data when the disk is damaged when raid3, 5, and 6 are not completed. Restoration: After writing, I still found that there were still big problems with the program structure. However, the changes took a lot of time and I just let it…

JavaScript gets the position of the element relative to the browser ie5, 6, 7, 8, 9, 10 test passed

Each element node in the dom has a layout positioning attribute offsetLeft relative to the parent node, offsetTop getPosition: function (el) { _x = 0, _y = 0; while (el.offsetParent !== null) { _x += el.offsetLeft; _y += el.offsetTop; el = el.offsetParent; } return { x: _x, y: _y }; }

How does the php array elegantly convert 1,2,4,5,6,7,9,11 into strings like ‘1,2,47,9,11’?

As the title There is a php array 1234 [1,2,4,5, 6,7,9,11] [7,11,16,17,18,33,102,103,555] Elegant conversion to 12 ‘1,2,4-7,9, 11’ ‘7,11,16-18,33,102-103,555’ like this What about strings? Thank you for your answer.

underscore knowledge points_error: partition(s) 1, 2, 3, 4, 5, 6, 7, 8, 9, 10,_cily_undefined’s blog

1. Installation Node. js –> npm install underscore Meteor.js –> meteor add underscore Require.js –> require([“underscore”], … Bower bower –> install underscore Component –> component install jashkenas/underscore Second, aggregate function (array or object) 1, each Syntax: _.each(list, iteratee, [context]) Description: Traverse all elements in the list, and call the iteratee function with each element as a parameter in order. If the context parameter is passed, bind iteratee to the context object. Each call to iteratee passes three parameters: (element, index, list). If list is a JavaScript object, the arguments to iteratee are (value, key, list)). Return a list to facilitate chain calls. Example: _.each([1, 2, 3], alert); => alerts each number in turn… _.each({one: 1, two: 2, three: 3}, alert); => alerts each number value in turn… 2, map Syntax: _.map(list, iteratee, [context]) Description: Generate a corresponding array by calling the conversion function (iteratee iterator) for each element in the list. iteratee passes three parameters: value, then the iteration index (or key Fool’s Wharf note: if the list is a JavaScript object, this parameter is the key), and the last one is a reference to the entire list. Example: _.map([1, 2, 3], function(num){ return num * 3; }); => [3,…

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