Programs & Examples On #Inner join

A database operation that combines the values of 2 tables based on a condition, or relationship, that exists between those tables.

What is the difference between "INNER JOIN" and "OUTER JOIN"?

In Simple Terms,

1.INNER JOIN OR EQUI JOIN : Returns the resultset that matches only the condition in both the tables.

2.OUTER JOIN : Returns the resultset of all the values from both the tables even if there is condition match or not.

3.LEFT JOIN : Returns the resultset of all the values from left table and only rows that match the condition in right table.

4.RIGHT JOIN : Returns the resultset of all the values from right table and only rows that match the condition in left table.

5.FULL JOIN : Full Join and Full outer Join are same.

Difference between JOIN and INNER JOIN

INNER JOIN = JOIN

INNER JOIN is the default if you don't specify the type when you use the word JOIN.

You can also use LEFT OUTER JOIN or RIGHT OUTER JOIN, in which case the word OUTER is optional, or you can specify CROSS JOIN.

OR

For an inner join, the syntax is:

SELECT ...
FROM TableA
[INNER] JOIN TableB

(in other words, the "INNER" keyword is optional - results are the same with or without it)

Inner join of DataTables in C#

I tried to do this in next way

public static DataTable JoinTwoTables(DataTable innerTable, DataTable outerTable)
        {
            DataTable resultTable = new DataTable();
            var innerTableColumns = new List<string>();
            foreach (DataColumn column in innerTable.Columns)
            {
                innerTableColumns.Add(column.ColumnName);
                resultTable.Columns.Add(column.ColumnName);
            }

            var outerTableColumns = new List<string>();
            foreach (DataColumn column in outerTable.Columns)
            {
                if (!innerTableColumns.Contains(column.ColumnName))
                {
                    outerTableColumns.Add(column.ColumnName);
                    resultTable.Columns.Add(column.ColumnName);
                }                    
            }

            for (int i = 0; i < innerTable.Rows.Count; i++)
            {
                var row = resultTable.NewRow();
                innerTableColumns.ForEach(x =>
                {
                    row[x] = innerTable.Rows[i][x];
                });
                outerTableColumns.ForEach(x => 
                {
                    row[x] = outerTable.Rows[i][x];
                });
                resultTable.Rows.Add(row);
            }
            return resultTable;
        }

What's the difference between INNER JOIN, LEFT JOIN, RIGHT JOIN and FULL JOIN?

An SQL JOIN clause is used to combine rows from two or more tables, based on a common field between them.

There are different types of joins available in SQL:

INNER JOIN: returns rows when there is a match in both tables.

LEFT JOIN: returns all rows from the left table, even if there are no matches in the right table.

RIGHT JOIN: returns all rows from the right table, even if there are no matches in the left table.

FULL JOIN: It combines the results of both left and right outer joins.

The joined table will contain all records from both the tables and fill in NULLs for missing matches on either side.

SELF JOIN: is used to join a table to itself as if the table were two tables, temporarily renaming at least one table in the SQL statement.

CARTESIAN JOIN: returns the Cartesian product of the sets of records from the two or more joined tables.

WE can take each first four joins in Details :

We have two tables with the following values.

TableA

id  firstName                  lastName
.......................................
1   arun                        prasanth                 
2   ann                         antony                   
3   sruthy                      abc                      
6   new                         abc                                           

TableB

id2 age Place
................
1   24  kerala
2   24  usa
3   25  ekm
5   24  chennai

....................................................................

INNER JOIN

Note :it gives the intersection of the two tables, i.e. rows they have common in TableA and TableB

Syntax

SELECT table1.column1, table2.column2...
  FROM table1
 INNER JOIN table2
    ON table1.common_field = table2.common_field;

Apply it in our sample table :

SELECT TableA.firstName,TableA.lastName,TableB.age,TableB.Place
  FROM TableA
 INNER JOIN TableB
    ON TableA.id = TableB.id2;

Result Will Be

firstName       lastName       age  Place
..............................................
arun            prasanth        24  kerala
ann             antony          24  usa
sruthy          abc             25  ekm

LEFT JOIN

Note : will give all selected rows in TableA, plus any common selected rows in TableB.

Syntax

SELECT table1.column1, table2.column2...
  FROM table1
  LEFT JOIN table2
    ON table1.common_field = table2.common_field;

Apply it in our sample table :

SELECT TableA.firstName,TableA.lastName,TableB.age,TableB.Place
  FROM TableA
  LEFT JOIN TableB
    ON TableA.id = TableB.id2;

Result

firstName                   lastName                    age   Place
...............................................................................
arun                        prasanth                    24    kerala
ann                         antony                      24    usa
sruthy                      abc                         25    ekm
new                         abc                         NULL  NULL

RIGHT JOIN

Note : will give all selected rows in TableB, plus any common selected rows in TableA.

Syntax

SELECT table1.column1, table2.column2...
  FROM table1
 RIGHT JOIN table2
    ON table1.common_field = table2.common_field;

Apply it in our sample table :

SELECT TableA.firstName,TableA.lastName,TableB.age,TableB.Place
  FROM TableA
 RIGHT JOIN TableB
    ON TableA.id = TableB.id2;

Result

firstName                   lastName                    age     Place
...............................................................................
arun                        prasanth                    24     kerala
ann                         antony                      24     usa
sruthy                      abc                         25     ekm
NULL                        NULL                        24     chennai

FULL JOIN

Note :It will return all selected values from both tables.

Syntax

SELECT table1.column1, table2.column2...
  FROM table1
  FULL JOIN table2
    ON table1.common_field = table2.common_field;

Apply it in our sample table :

SELECT TableA.firstName,TableA.lastName,TableB.age,TableB.Place
  FROM TableA
  FULL JOIN TableB
    ON TableA.id = TableB.id2;

Result

firstName                   lastName                    age    Place
...............................................................................
arun                        prasanth                    24    kerala
ann                         antony                      24    usa
sruthy                      abc                         25    ekm
new                         abc                         NULL  NULL
NULL                        NULL                        24    chennai

Interesting Fact

For INNER joins the order doesn't matter

For (LEFT, RIGHT or FULL) OUTER joins,the order matter

Better to go check this Link it will give you interesting details about join order

SQL Server - INNER JOIN WITH DISTINCT

Try this:

select distinct a.FirstName, a.LastName, v.District
from AddTbl a 
  inner join ValTbl v
  on a.LastName = v.LastName
order by a.FirstName;

Or this (it does the same, but the syntax is different):

select distinct a.FirstName, a.LastName, v.District
from AddTbl a, ValTbl v
where a.LastName = v.LastName
order by a.FirstName;

INNER JOIN vs INNER JOIN (SELECT . FROM)

You are correct. You did exactly the right thing, checking the query plan rather than trying to second-guess the optimiser. :-)

SQL Inner join 2 tables with multiple column conditions and update

You should join T1 and T2 tables using sql joins in order to analyze from two tables. Link for learn joins : https://www.w3schools.com/sql/sql_join.asp

SQL Inner join more than two tables

SELECT eb.n_EmpId,
   em.s_EmpName,
   deg.s_DesignationName,
   dm.s_DeptName
FROM tbl_EmployeeMaster em
 INNER JOIN tbl_DesignationMaster deg ON em.n_DesignationId=deg.n_DesignationId
 INNER JOIN tbl_DepartmentMaster dm ON dm.n_DeptId = em.n_DepartmentId
 INNER JOIN tbl_EmployeeBranch eb ON eb.n_BranchId = em.n_BranchId;

Inner join with 3 tables in mysql

Almost correctly.. Look at the joins, you are referring the wrong fields

SELECT student.firstname,
       student.lastname,
       exam.name,
       exam.date,
       grade.grade
  FROM grade
 INNER JOIN student ON student.studentId = grade.fk_studentId
 INNER JOIN exam ON exam.examId = grade.fk_examId
 ORDER BY exam.date

How to use mysql JOIN without ON condition?

MySQL documentation covers this topic.

Here is a synopsis. When using join or inner join, the on condition is optional. This is different from the ANSI standard and different from almost any other database. The effect is a cross join. Similarly, you can use an on clause with cross join, which also differs from standard SQL.

A cross join creates a Cartesian product -- that is, every possible combination of 1 row from the first table and 1 row from the second. The cross join for a table with three rows ('a', 'b', and 'c') and a table with four rows (say 1, 2, 3, 4) would have 12 rows.

In practice, if you want to do a cross join, then use cross join:

from A cross join B

is much better than:

from A, B

and:

from A join B -- with no on clause

The on clause is required for a right or left outer join, so the discussion is not relevant for them.

If you need to understand the different types of joins, then you need to do some studying on relational databases. Stackoverflow is not an appropriate place for that level of discussion.

SQL DELETE with INNER JOIN

if the database is InnoDB you dont need to do joins in deletion. only

DELETE FROM spawnlist WHERE spawnlist.type = "monster";

can be used to delete the all the records that linked with foreign keys in other tables, to do that you have to first linked your tables in design time.

CREATE TABLE IF NOT EXIST spawnlist (
  npc_templateid VARCHAR(20) NOT NULL PRIMARY KEY

)ENGINE=InnoDB;

CREATE TABLE IF NOT EXIST npc (
  idTemplate VARCHAR(20) NOT NULL,

  FOREIGN KEY (idTemplate) REFERENCES spawnlist(npc_templateid) ON DELETE CASCADE

)ENGINE=InnoDB;

if you uses MyISAM you can delete records joining like this

DELETE a,b
FROM `spawnlist` a
JOIN `npc` b
ON a.`npc_templateid` = b.`idTemplate`
WHERE a.`type` = 'monster';

in first line i have initialized the two temp tables for delet the record, in second line i have assigned the existance table to both a and b but here i have linked both tables together with join keyword, and i have matched the primary and foreign key for both tables that make link, in last line i have filtered the record by field to delete.

Multiple INNER JOIN SQL ACCESS

Thanks HansUp for your answer, it is very helpful and it works!

I found three patterns working in Access, yours is the best, because it works in all cases.

  • INNER JOIN, your variant. I will call it "closed set pattern". It is possible to join more than two tables to the same table with good performance only with this pattern.

    SELECT C_Name, cr.P_FirstName+" "+cr.P_SurName AS ClassRepresentativ, cr2.P_FirstName+" "+cr2.P_SurName AS ClassRepresentativ2nd
    FROM
         ((class
           INNER JOIN person AS cr 
           ON class.C_P_ClassRep=cr.P_Nr
         )
         INNER JOIN person AS cr2
         ON class.C_P_ClassRep2nd=cr2.P_Nr
      )
    

    ;

  • INNER JOIN "chained-set pattern"

    SELECT C_Name, cr.P_FirstName+" "+cr.P_SurName AS ClassRepresentativ, cr2.P_FirstName+" "+cr2.P_SurName AS ClassRepresentativ2nd
    FROM person AS cr
    INNER JOIN ( class 
       INNER JOIN ( person AS cr2
       ) ON class.C_P_ClassRep2nd=cr2.P_Nr
    ) ON class.C_P_ClassRep=cr.P_Nr
    ;
    
  • CROSS JOIN with WHERE

    SELECT C_Name, cr.P_FirstName+" "+cr.P_SurName AS ClassRepresentativ, cr2.P_FirstName+" "+cr2.P_SurName AS ClassRepresentativ2nd
    FROM class, person AS cr, person AS cr2
    WHERE class.C_P_ClassRep=cr.P_Nr AND class.C_P_ClassRep2nd=cr2.P_Nr
    ;
    

MySQL INNER JOIN select only one row from second table

   SELECT u.* 
        FROM users AS u
        INNER JOIN (
            SELECT p.*,
             @num := if(@id = user_id, @num + 1, 1) as row_number,
             @id := user_id as tmp
            FROM payments AS p,
                 (SELECT @num := 0) x,
                 (SELECT @id := 0) y
            ORDER BY p.user_id ASC, date DESC)
        ON (p.user_id = u.id) and (p.row_number=1)
        WHERE u.package = 1

SQL Inner-join with 3 tables?

SELECT column_Name1,column_name2,......
  From tbl_name1,tbl_name2,tbl_name3
  where tbl_name1.column_name = tbl_name2.column_name 
  and tbl_name2.column_name = tbl_name3.column_name

Update statement with inner join on Oracle

UPDATE (SELECT T.FIELD A, S.FIELD B
FROM TABLE_T T INNER JOIN TABLE_S S
ON T.ID = S.ID)
SET B = A;

A and B are alias fields, you do not need to point the table.

INNER JOIN ON vs WHERE clause

They have a different human-readable meaning.

However, depending on the query optimizer, they may have the same meaning to the machine.

You should always code to be readable.

That is to say, if this is a built-in relationship, use the explicit join. if you are matching on weakly related data, use the where clause.

Insert using LEFT JOIN and INNER JOIN

you can't use VALUES clause when inserting data using another SELECT query. see INSERT SYNTAX

INSERT INTO user
(
 id, name, username, email, opted_in
)
(
    SELECT id, name, username, email, opted_in
    FROM user
         LEFT JOIN user_permission AS userPerm
            ON user.id = userPerm.user_id
);

Order by in Inner Join

Avoid SELECT * in your main query.

Avoid duplicate columns: the JOIN condition ensures One.One_Name and two.One_Name will be equal therefore you don't need to return both in the SELECT clause.

Avoid duplicate column names: rename One.ID and Two.ID using 'aliases'.

Add an ORDER BY clause using the column names ('alises' where applicable) from the SELECT clause.

Suggested re-write:

SELECT T1.ID AS One_ID, T1.One_Name, 
       T2.ID AS Two_ID, T2.Two_name
  FROM One AS T1
       INNER JOIN two AS T2
          ON T1.One_Name = T2.One_Name
 ORDER 
    BY One_ID;

Eliminating duplicate values based on only one column of the table

I solve such queries using this pattern:

SELECT *
FROM t
WHERE t.field=(
  SELECT MAX(t.field) 
  FROM t AS t0 
  WHERE t.group_column1=t0.group_column1
    AND t.group_column2=t0.group_column2 ...)

That is it will select records where the value of a field is at its max value. To apply it to your query I used the common table expression so that I don't have to repeat the JOIN twice:

WITH site_history AS (
  SELECT sites.siteName, sites.siteIP, history.date
  FROM sites
  JOIN history USING (siteName)
)
SELECT *
FROM site_history h
WHERE date=(
  SELECT MAX(date) 
  FROM site_history h0 
  WHERE h.siteName=h0.siteName)
ORDER BY siteName

It's important to note that it works only if the field we're calculating the maximum for is unique. In your example the date field should be unique for each siteName, that is if the IP can't be changed multiple times per millisecond. In my experience this is commonly the case otherwise you don't know which record is the newest anyway. If the history table has an unique index for (site, date), this query is also very fast, index range scan on the history table scanning just the first item can be used.

Update Query with INNER JOIN between tables in 2 different databases on 1 server

Update one table using Inner Join

  UPDATE Table1 SET name=ml.name
FROM table1 t inner JOIN
Table2 ml ON t.ID= ml.ID  

Is having an 'OR' in an INNER JOIN condition a bad idea?

I use following code for get different result from condition That worked for me.


Select A.column, B.column
FROM TABLE1 A
INNER JOIN
TABLE2 B
ON A.Id = (case when (your condition) then b.Id else (something) END)

Trying to use INNER JOIN and GROUP BY SQL with SUM Function, Not Working

Use subquery

SELECT * FROM RES_DATA inner join (SELECT [CUSTOMER ID], sum([TOTAL AMOUNT]) FROM INV_DATA group by [CUSTOMER ID]) T on RES_DATA.[CUSTOMER ID] = t.[CUSTOMER ID]

How can I delete using INNER JOIN with SQL Server?

Try this:

DELETE FROM WorkRecord2 
       FROM Employee 
Where EmployeeRun=EmployeeNo
      And Company = '1' 
      AND Date = '2013-05-06'

using where and inner join in mysql

Try this :

SELECT
    (
      SELECT
          `NAME`
      FROM
          locations
      WHERE
          ID = school_locations.LOCATION_ID
    ) as `NAME`
FROM
     school_locations
WHERE
     (
      SELECT
          `TYPE`
      FROM
          locations
      WHERE
          ID = school_locations.LOCATION_ID
     ) = 'coun';

Using DISTINCT inner join in SQL

Is this what you mean?

SELECT DISTINCT C.valueC
FROM 
C
INNER JOIN B ON C.id = B.lookupC
INNER JOIN A ON B.id = A.lookupB

SQL Server - inner join when updating

This should do it:

UPDATE ProductReviews
SET    ProductReviews.status = '0'
FROM   ProductReviews
       INNER JOIN products
         ON ProductReviews.pid = products.id
WHERE  ProductReviews.id = '17190'
       AND products.shopkeeper = '89137'

How to select all rows which have same value in some column

SELECT * FROM employees e1, employees e2 
WHERE e1.phoneNumber = e2.phoneNumber 
AND e1.id != e2.id;

Update : for better performance and faster query its good to add e1 before *

SELECT e1.* FROM employees e1, employees e2 
WHERE e1.phoneNumber = e2.phoneNumber 
AND e1.id != e2.id;

Deserializing JSON array into strongly typed .NET object

Json.NET - Documentation

http://james.newtonking.com/json/help/index.html?topic=html/SelectToken.htm

Interpretation for the author

var o = JObject.Parse(response);
var a = o.SelectToken("data").Select(jt => jt.ToObject<TheUser>()).ToList();

Check if application is on its first run

    import java.io.File;
    import java.io.FileOutputStream;
    import java.io.IOException;
    import java.io.RandomAccessFile;
    import java.util.UUID;

    import android.content.Context;

    public class Util {
        // ===========================================================
        //
        // ===========================================================

        private static final String INSTALLATION = "INSTALLATION";

        public synchronized static boolean isFirstLaunch(Context context) {
            String sID = null;
            boolean launchFlag = false;
            if (sID == null) {
                File installation = new File(context.getFilesDir(), INSTALLATION);
                try {
                    if (!installation.exists()) {
                    launchFlag = true;                          
                        writeInstallationFile(installation);
                    }
                    sID = readInstallationFile(installation);

                } catch (Exception e) {
                    throw new RuntimeException(e);
                }
            }
            return launchFlag;
        }

        private static String readInstallationFile(File installation) throws IOException {
            RandomAccessFile f = new RandomAccessFile(installation, "r");// read only mode
            byte[] bytes = new byte[(int) f.length()];
            f.readFully(bytes);
            f.close();

            return new String(bytes);
        }

        private static void writeInstallationFile(File installation) throws IOException {
            FileOutputStream out = new FileOutputStream(installation);
            String id = UUID.randomUUID().toString();
            out.write(id.getBytes());
            out.close();
        }
    }

> Usage (in class extending android.app.Activity)

Util.isFirstLaunch(this);

Vim and Ctags tips and tricks

Ctrl+] - go to definition
Ctrl+T - Jump back from the definition.
Ctrl+W Ctrl+] - Open the definition in a horizontal split

Add these lines in vimrc
map <C-\> :tab split<CR>:exec("tag ".expand("<cword>"))<CR>
map <A-]> :vsp <CR>:exec("tag ".expand("<cword>"))<CR>

Ctrl+\ - Open the definition in a new tab
Alt+] - Open the definition in a vertical split

After the tags are generated. You can use the following keys to tag into and tag out of functions:

Ctrl+Left MouseClick - Go to definition
Ctrl+Right MouseClick - Jump back from definition

Change SQLite database mode to read-write

To share personal experience I encountered with this error that eventually fix both. Might not necessarily be related to your issue but it appears this error is so generic that it can be attributed to gazillion things.

  1. Database instance open in another application. My DB appeared to have been in a "locked" state so it transition to read only mode. I was able to track it down by stopping the a 2nd instance of the application sharing the DB.

  2. Directory tree permission - please be sure to ensure user account has permission not just at the file level but at the entire upper directory level all the way to / level.

Thanks

How does MySQL CASE work?

CASE is more like a switch statement. It has two syntaxes you can use. The first lets you use any compare statements you want:

CASE 
    WHEN user_role = 'Manager' then 4
    WHEN user_name = 'Tom' then 27
    WHEN columnA <> columnB then 99
    ELSE -1 --unknown
END

The second style is for when you are only examining one value, and is a little more succinct:

CASE user_role
    WHEN 'Manager' then 4
    WHEN 'Part Time' then 7
    ELSE -1 --unknown
END

Erase whole array Python

It's simple:

array = []

will set array to be an empty list. (They're called lists in Python, by the way, not arrays)

If that doesn't work for you, edit your question to include a code sample that demonstrates your problem.

Concatenating elements in an array to a string

take a look at generic method to print all elements in an array

but in short, the Arrays.toString(arr) is just a easy way of printing the content of a primative array.

How to display text in pygame?

This is slighly more OS independent way:

# do this init somewhere
import pygame
pygame.init()
screen = pygame.display.set_mode((640, 480))
font = pygame.font.Font(pygame.font.get_default_font(), 36)

# now print the text
text_surface = font.render('Hello world', antialias=True, color=(0, 0, 0))
screen.blit(text_surface, dest=(0,0))

difference between @size(max = value ) and @min(value) @max(value)

@Min and @Max are used for validating numeric fields which could be String(representing number), int, short, byte etc and their respective primitive wrappers.

@Size is used to check the length constraints on the fields.

As per documentation @Size supports String, Collection, Map and arrays while @Min and @Max supports primitives and their wrappers. See the documentation.

Exec : display stdout "live"

child_process.spawn returns an object with stdout and stderr streams. You can tap on the stdout stream to read data that the child process sends back to Node. stdout being a stream has the "data", "end", and other events that streams have. spawn is best used to when you want the child process to return a large amount of data to Node - image processing, reading binary data etc.

so you can solve your problem using child_process.spawn as used below.

var spawn = require('child_process').spawn,
ls = spawn('coffee -cw my_file.coffee');

ls.stdout.on('data', function (data) {
  console.log('stdout: ' + data.toString());
});

ls.stderr.on('data', function (data) {
  console.log('stderr: ' + data.toString());
});

ls.on('exit', function (code) {
  console.log('code ' + code.toString());
});

Export multiple classes in ES6 modules

For exporting the instances of the classes you can use this syntax:

// export index.js
const Foo = require('./my/module/foo');
const Bar = require('./my/module/bar');

module.exports = {
    Foo : new Foo(),
    Bar : new Bar()
};

// import and run method
const {Foo,Bar} = require('module_name');
Foo.test();

Replacing Pandas or Numpy Nan with a None to use with MysqlDB

You can replace nan with None in your numpy array:

>>> x = np.array([1, np.nan, 3])
>>> y = np.where(np.isnan(x), None, x)
>>> print y
[1.0 None 3.0]
>>> print type(y[1])
<type 'NoneType'>

How to squash commits in git after they have been pushed?

For squashing two commits, one of which was already pushed, on a single branch the following worked:

git rebase -i HEAD~2
    [ pick     older-commit  ]
    [ squash   newest-commit ]
git push --force

By default, this will include the commit message of the newest commit as a comment on the older commit.

Microsoft Excel mangles Diacritics in .csv files?

Check the encoding in which you are generating the file, to make excel display the file correctly you must use the system default codepage.

Wich language are you using? if it's .Net you only need to use Encoding.Default while generating the file.

Could not open ServletContext resource

Try to use classpath*: prefix instead.

http://static.springsource.org/spring/docs/3.0.x/spring-framework-reference/html/resources.html#resources-classpath-wildcards

Also please try to deploy exploded war, to ensure that all files are there.

Invoking a static method using reflection

public class Add {
    static int add(int a, int b){
        return (a+b);
    }
}

In the above example, 'add' is a static method that takes two integers as arguments.

Following snippet is used to call 'add' method with input 1 and 2.

Class myClass = Class.forName("Add");
Method method = myClass.getDeclaredMethod("add", int.class, int.class);
Object result = method.invoke(null, 1, 2);

Reference link.

accessing a docker container from another container

Using docker-compose, services are exposed to each other by name by default. Docs.
You could also specify an alias like;

version: '2.1'
services:
  mongo:
    image: mongo:3.2.11
  redis:
    image: redis:3.2.10
  api:
    image: some-image
    depends_on:
      - mongo
      - solr
    links:
      - "mongo:mongo.openconceptlab.org"
      - "solr:solr.openconceptlab.org"
      - "some-service:some-alias"

And then access the service using the specified alias as a host name, e.g mongo.openconceptlab.org for mongo in this case.

Console app arguments, how arguments are passed to Main method

The main method of the runtime engine looks something like int main(int argc, char *argv[]), where argc is a count of the number of arguments and argv is an array of pointers to each. The runtime engine converts this into a form that is more natural to c#.

Prior to that main method being called, everything is in assembly language. It has access to the command line arguments (because the operating system makes that available to every process that starts), but that assembly language needs to convert a single string of the full command line into multiple substrings (using whitespace to separate them) before it's ready to pass them into main().

Reading DataSet

If this is from a SQL Server datebase you could issue this kind of query...

Select Top 1 DepartureTime From TrainSchedule where DepartureTime > 
GetUTCDate()
Order By DepartureTime ASC

GetDate() could also be used, not sure how dates are being stored.

I am not sure how the data is being stored and/or read.

Django CSRF check failing with an Ajax POST request

Use Firefox with Firebug. Open the 'Console' tab while firing the ajax request. With DEBUG=True you get the nice django error page as response and you can even see the rendered html of the ajax response in the console tab.

Then you will know what the error is.

What are the aspect ratios for all Android phone and tablet devices?

I researched the same thing several months ago looking at dozens of the most popular Android devices. I found that every Android device had one of the following aspect ratios (from most square to most rectangular):

  • 4:3
  • 3:2
  • 8:5
  • 5:3
  • 16:9

And if you consider portrait devices separate from landscape devices you'll also find the inverse of those ratios (3:4, 2:3, 5:8, 3:5, and 9:16)


More complete answer here: stackoverflow community spreadsheet of Android device resolutions and DPIs

JQuery/Javascript: check if var exists

Before each of your conditional statements, you could do something like this:

var pagetype = pagetype || false;
if (pagetype === 'something') {
    //do stuff
}

Checking for duplicate strings in JavaScript array

Using ES6 features

function checkIfDuplicateExists(w){
    return new Set(w).size !== w.length 
}

console.log(
    checkIfDuplicateExists(["a", "b", "c", "a"])
// true
);

console.log(
    checkIfDuplicateExists(["a", "b", "c"]))
//false

Bootstrap 3: Using img-circle, how to get circle from non-square image?

I use these two methods depending on the usage. FIDDLE

<div class="img-div">
<img src="http://placekitten.com/g/400/200" />
</div>
<div class="circle-image"></div>

div.img-div{
    height:200px;
    width:200px;
    overflow:hidden;
    border-radius:50%;
}

.img-div img{
    -webkit-transform:translate(-50%);
    margin-left:100px;
}

.circle-image{
    width:200px;
    height:200px;
    border-radius:50%;
    background-image:url("http://placekitten.com/g/200/400");
    display:block;
    background-position-y:25% 
}

MVC : The parameters dictionary contains a null entry for parameter 'k' of non-nullable type 'System.Int32'

It seems that your action needs k but ModelBinder can not find it (from form, or request or view data or ..) Change your action to this:

public ActionResult DetailsData(int? k)
    {

        EmployeeContext Ec = new EmployeeContext();
        if (k != null)
        {
           Employee emp = Ec.Employees.Single(X => X.EmpId == k.Value);

           return View(emp);
        }
        return View();
    }

How to sort List of objects by some property

Using Comparator

For Example:

class Score {

    private String name;
    private List<Integer> scores;
    // +accessor methods
}

    Collections.sort(scores, new Comparator<Score>() {

        public int compare(Score o1, Score o2) {
            // compare two instance of `Score` and return `int` as result.
            return o2.getScores().get(0).compareTo(o1.getScores().get(0));
        }
    });

With Java 8 onwards, you can simply use lambda expression to represent Comparator instance.

Collections.sort(scores, (s1, s2) -> { /* compute and return int */ });

best OCR (Optical character recognition) example in android

Like you I also faced many problems implementing OCR in Android, but after much Googling I found the solution, and it surely is the best example of OCR.

Let me explain using step-by-step guidance.

First, download the source code from https://github.com/rmtheis/tess-two.

Import all three projects. After importing you will get an error. To solve the error you have to create a res folder in the tess-two project

enter image description here

First, just create res folder in tess-two by tess-two->RightClick->new Folder->Name it "res"

After doing this in all three project the error should be gone.

Now download the source code from https://github.com/rmtheis/android-ocr, here you will get best example.

Now you just need to import it into your workspace, but first you have to download android-ndk from this site:

http://developer.android.com/tools/sdk/ndk/index.html i have windows 7 - 32 bit PC so I have download http://dl.google.com/android/ndk/android-ndk-r9-windows-x86.zip this file

Now extract it suppose I have extract it into E:\Software\android-ndk-r9 so I will set this path on Environment Variable

Right Click on MyComputer->Property->Advance-System-Settings->Advance->Environment Variable-> find PATH on second below Box and set like path like below picture

enter image description here

done it

Now open cmd and go to on D:\Android Workspace\tess-two like below

enter image description here

If you have successfully set up environment variable of NDK then just type ndk-build just like above picture than enter you will not get any kind of error and all file will be compiled successfully:

Now download other source code also from https://github.com/rmtheis/tess-two , and extract and import it and give it name OCRTest, like in my PC which is in D:\Android Workspace\OCRTest

enter image description here

Import test-two in this and run OCRTest and run it; you will get the best example of OCR.

Pretty-print an entire Pandas Series / DataFrame

Try using display() function. This would automatically use Horizontal and vertical scroll bars and with this you can display different datasets easily instead of using print().

display(dataframe)

display() supports proper alignment also.

However if you want to make the dataset more beautiful you can check pd.option_context(). It has lot of options to clearly show the dataframe.

Note - I am using Jupyter Notebooks.

Using BigDecimal to work with currencies

I would recommend a little research on Money Pattern. Martin Fowler in his book Analysis pattern has covered this in more detail.

public class Money {

    private static final Currency USD = Currency.getInstance("USD");
    private static final RoundingMode DEFAULT_ROUNDING = RoundingMode.HALF_EVEN;

    private final BigDecimal amount;
    private final Currency currency;   

    public static Money dollars(BigDecimal amount) {
        return new Money(amount, USD);
    }

    Money(BigDecimal amount, Currency currency) {
        this(amount, currency, DEFAULT_ROUNDING);
    }

    Money(BigDecimal amount, Currency currency, RoundingMode rounding) {
        this.currency = currency;      
        this.amount = amount.setScale(currency.getDefaultFractionDigits(), rounding);
    }

    public BigDecimal getAmount() {
        return amount;
    }

    public Currency getCurrency() {
        return currency;
    }

    @Override
    public String toString() {
        return getCurrency().getSymbol() + " " + getAmount();
    }

    public String toString(Locale locale) {
        return getCurrency().getSymbol(locale) + " " + getAmount();
    }   
}

Coming to the usage:

You would represent all monies using Money object as opposed to BigDecimal. Representing money as big decimal will mean that you will have the to format the money every where you display it. Just imagine if the display standard changes. You will have to make the edits all over the place. Instead using the Money pattern you centralize the formatting of money to a single location.

Money price = Money.dollars(38.28);
System.out.println(price);

How to include clean target in Makefile?

The best thing is probably to create a variable that holds your binaries:

binaries=code1 code2

Then use that in the all-target, to avoid repeating:

all: clean $(binaries)

Now, you can use this with the clean-target, too, and just add some globs to catch object files and stuff:

.PHONY: clean

clean:
    rm -f $(binaries) *.o

Note use of the .PHONY to make clean a pseudo-target. This is a GNU make feature, so if you need to be portable to other make implementations, don't use it.

The current .NET SDK does not support targeting .NET Standard 2.0 error in Visual Studio 2017 update 15.3

while the above answers didn't solve my problem. I finally solved it by specifically going to this link https://www.microsoft.com/net/download/visual-studio-sdks and download the required sdk for Visual Studio. It was really confusing and i don't understand why but that solved my problem

How to cancel a local git commit

The first thing you should do is to determine whether you want to keep the local changes before you delete the commit message.

Use git log to show current commit messages, then find the commit_id before the commit that you want to delete, not the commit you want to delete.

If you want to keep the locally changed files, and just delete commit message:

git reset --soft commit_id

If you want to delete all locally changed files and the commit message:

git reset --hard commit_id

That's the difference of soft and hard

How can I strip first and last double quotes?

Remove a determinated string from start and end from a string.

s = '""Hello World""'
s.strip('""')

> 'Hello World'

How to parse Excel (XLS) file in Javascript/HTML5

_x000D_
_x000D_
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>_x000D_
<script src="https://cdnjs.cloudflare.com/ajax/libs/xlsx/0.8.0/jszip.js"></script>_x000D_
<script src="https://cdnjs.cloudflare.com/ajax/libs/xlsx/0.8.0/xlsx.js"></script>_x000D_
<script>_x000D_
    var ExcelToJSON = function() {_x000D_
_x000D_
      this.parseExcel = function(file) {_x000D_
        var reader = new FileReader();_x000D_
_x000D_
        reader.onload = function(e) {_x000D_
          var data = e.target.result;_x000D_
          var workbook = XLSX.read(data, {_x000D_
            type: 'binary'_x000D_
          });_x000D_
          workbook.SheetNames.forEach(function(sheetName) {_x000D_
            // Here is your object_x000D_
            var XL_row_object = XLSX.utils.sheet_to_row_object_array(workbook.Sheets[sheetName]);_x000D_
            var json_object = JSON.stringify(XL_row_object);_x000D_
            console.log(JSON.parse(json_object));_x000D_
            jQuery( '#xlx_json' ).val( json_object );_x000D_
          })_x000D_
        };_x000D_
_x000D_
        reader.onerror = function(ex) {_x000D_
          console.log(ex);_x000D_
        };_x000D_
_x000D_
        reader.readAsBinaryString(file);_x000D_
      };_x000D_
  };_x000D_
_x000D_
  function handleFileSelect(evt) {_x000D_
    _x000D_
    var files = evt.target.files; // FileList object_x000D_
    var xl2json = new ExcelToJSON();_x000D_
    xl2json.parseExcel(files[0]);_x000D_
  }_x000D_
_x000D_
_x000D_
 _x000D_
</script>_x000D_
_x000D_
<form enctype="multipart/form-data">_x000D_
    <input id="upload" type=file  name="files[]">_x000D_
</form>_x000D_
_x000D_
    <textarea class="form-control" rows=35 cols=120 id="xlx_json"></textarea>_x000D_
_x000D_
    <script>_x000D_
        document.getElementById('upload').addEventListener('change', handleFileSelect, false);_x000D_
_x000D_
    </script>
_x000D_
_x000D_
_x000D_

How To Check If A Key in **kwargs Exists?

You can discover those things easily by yourself:

def hello(*args, **kwargs):
    print kwargs
    print type(kwargs)
    print dir(kwargs)

hello(what="world")

how to convert binary string to decimal?

The parseInt function converts strings to numbers, and it takes a second argument specifying the base in which the string representation is:

var digit = parseInt(binary, 2);

See it in action.

How do I show/hide a UIBarButtonItem?

It is possible to hide a button in place without changing its width or removing it from the bar. If you set the style to plain, remove the title, and disable the button, it will disappear. To restore it, just reverse your changes.

-(void)toggleBarButton:(bool)show
{
    if (show) {
        btn.style = UIBarButtonItemStyleBordered;
        btn.enabled = true;
        btn.title = @"MyTitle";
    } else {
        btn.style = UIBarButtonItemStylePlain;
        btn.enabled = false;
        btn.title = nil;
    }
}

Remove the newline character in a list read from a file

You can use the strip() function to remove trailing (and leading) whitespace; passing it an argument will let you specify which whitespace:

for i in range(len(lists)):
    grades.append(lists[i].strip('\n'))

It looks like you can just simplify the whole block though, since if your file stores one ID per line grades is just lists with newlines stripped:

Before

lists = files.readlines()
grades = []

for i in range(len(lists)):
    grades.append(lists[i].split(","))

After

grades = [x.strip() for x in files.readlines()]

(the above is a list comprehension)


Finally, you can loop over a list directly, instead of using an index:

Before

for i in range(len(grades)):
    # do something with grades[i]

After

for thisGrade in grades:
    # do something with thisGrade

How to succinctly write a formula with many variables from a data frame?

An extension of juba's method is to use reformulate, a function which is explicitly designed for such a task.

## Create a formula for a model with a large number of variables:
xnam <- paste("x", 1:25, sep="")

reformulate(xnam, "y")
y ~ x1 + x2 + x3 + x4 + x5 + x6 + x7 + x8 + x9 + x10 + x11 + 
    x12 + x13 + x14 + x15 + x16 + x17 + x18 + x19 + x20 + x21 + 
    x22 + x23 + x24 + x25

For the example in the OP, the easiest solution here would be

# add y variable to data.frame d
d <- cbind(y, d)
reformulate(names(d)[-1], names(d[1]))
y ~ x1 + x2 + x3

or

mod <- lm(reformulate(names(d)[-1], names(d[1])), data=d)

Note that adding the dependent variable to the data.frame in d <- cbind(y, d) is preferred not only because it allows for the use of reformulate, but also because it allows for future use of the lm object in functions like predict.

ASP.Net MVC - Read File from HttpPostedFileBase without save

A slight change to Thangamani Palanisamy answer, which allows the Binary reader to be disposed and corrects the input length issue in his comments.

string result = string.Empty;

using (BinaryReader b = new BinaryReader(file.InputStream))
{
  byte[] binData = b.ReadBytes(file.ContentLength);
  result = System.Text.Encoding.UTF8.GetString(binData);
}

Jquery UI tooltip does not support html content

None of the solutions above worked for me. This one works for me:

$(document).ready(function()
{
    $('body').tooltip({
        selector: '[data-toggle="tooltip"]',
        html: true
     });
});

Android: Difference between Parcelable and Serializable?

I am late in answer, but posting with hope that it will help others.

In terms of Speed, Parcelable > Serializable. But, Custom Serializable is exception. It is almost in range of Parcelable or even more faster.

Reference : https://www.geeksforgeeks.org/customized-serialization-and-deserialization-in-java/

Example :

Custom Class to be serialized

class MySerialized implements Serializable { 

    String deviceAddress = "MyAndroid-04"; 

    transient String token = "AABCDS"; // sensitive information which I do not want to serialize

    private void writeObject(ObjectOutputStream oos) throws Exception {
        oos.defaultWriteObject();
        oos.writeObject("111111" + token); // Encrypted token to be serialized
    }

    private void readObject(ObjectInputStream ois) throws Exception {
        ois.defaultReadObject(); 
        token = ((String) ois.readObject()).subString(6);  // Decrypting token
    }

}

difference between System.out.println() and System.err.println()

Those commands use different output streams. By default both messages will be printed on console but it's possible for example to redirect one or both of these to a file.

java MyApp 2>errors.txt

This will redirect System.err to errors.txt file.

How to change XML Attribute

Using LINQ to xml if you are using framework 3.5:

using System.Xml.Linq;

XDocument xmlFile = XDocument.Load("books.xml"); 

var query = from c in xmlFile.Elements("catalog").Elements("book")    
            select c; 

foreach (XElement book in query) 
{
   book.Attribute("attr1").Value = "MyNewValue";
}

xmlFile.Save("books.xml");

Simple search MySQL database using php

First add HTML code:

<form action="" method="post">
<input type="text" name="search">
<input type="submit" name="submit" value="Search">
</form>

Now added PHP code:

<?php
$search_value=$_POST["search"];
$con=new mysqli($servername,$username,$password,$dbname);
if($con->connect_error){
    echo 'Connection Faild: '.$con->connect_error;
    }else{
        $sql="select * from information where First_Name like '%$search_value%'";

        $res=$con->query($sql);

        while($row=$res->fetch_assoc()){
            echo 'First_name:  '.$row["First_Name"];


            }       

        }
?>

VueJS conditionally add an attribute for an element

<input :required="condition">

You don't need <input :required="test ? true : false"> because if test is truthy you'll already get the required attribute, and if test is falsy you won't get the attribute. The true : false part is redundant, much like this...

if (condition) {
    return true;
} else {
    return false;
}
// or this...
return condition ? true : false;
// can *always* be replaced by...
return (condition); // parentheses generally not needed

The simplest way of doing this binding, then, is <input :required="condition">

Only if the test (or condition) can be misinterpreted would you need to do something else; in that case Syed's use of !! does the trick.
  <input :required="!!condition">

How to pick just one item from a generator?

generator = myfunct()
while True:
   my_element = generator.next()

make sure to catch the exception thrown after the last element is taken

How do you use MySQL's source command to import large files in windows

On Windows this should work (note the forwardslash and that the whole path is not quoted and that spaces are allowed)

USE yourdb;

SOURCE D:/My Folder with spaces/Folder/filetoimport.sql;

Calculating time difference in Milliseconds

No, it doesn't mean it's taking 0ms - it shows it's taking a smaller amount of time than you can measure with currentTimeMillis(). That may well be 10ms or 15ms. It's not a good method to call for timing; it's more appropriate for getting the current time.

To measure how long something takes, consider using System.nanoTime instead. The important point here isn't that the precision is greater, but that the resolution will be greater... but only when used to measure the time between two calls. It must not be used as a "wall clock".

Note that even System.nanoTime just uses "the most accurate timer on your system" - it's worth measuring how fine-grained that is. You can do that like this:

public class Test {
    public static void main(String[] args) throws Exception {

        long[] differences = new long[5];
        long previous = System.nanoTime();
        for (int i = 0; i < 5; i++) {
            long current;
            while ((current = System.nanoTime()) == previous) {
                // Do nothing...
            }
            differences[i] = current - previous;
            previous = current;            
        }

        for (long difference : differences) {
            System.out.println(difference);
        }
    }
}

On my machine that shows differences of about 466 nanoseconds... so I can't possibly expect to measure the time taken for something quicker than that. (And other times may well be roughly multiples of that amount of time.)

How to convert a char array to a string?

The string class has a constructor that takes a NULL-terminated C-string:

char arr[ ] = "This is a test";

string str(arr);


//  You can also assign directly to a string.
str = "This is another string";

// or
str = arr;

Show/hide forms using buttons and JavaScript

Use the following code fragment to hide the form on button click.

document.getElementById("your form id").style.display="none";

And the following code to display it:

document.getElementById("your form id").style.display="block";

Or you can use the same function for both purposes:

function asd(a)
{
    if(a==1)
        document.getElementById("asd").style.display="none";
    else
        document.getElementById("asd").style.display="block";
}

And the HTML:

<form id="asd">form </form>
<button onclick="asd(1)">Hide</button>
<button onclick="asd(2)">Show</button>

Which command do I use to generate the build of a Vue app?

The commands for what specific codes to run are listed inside your package.json file under scripts. Here is an example of mine:

"scripts": {
    "serve": "vue-cli-service serve",
    "build": "vue-cli-service build",
    "lint": "vue-cli-service lint"
  },

If you are looking to run your site locally, you can test it with

npm serve

If you are looking to prep your site for production, you would use

npm build

This command will generate a dist folder that has a compressed version of your site.

The server principal is not able to access the database under the current security context in SQL Server MS 2012

SQL Logins are defined at the server level, and must be mapped to Users in specific databases.

In SSMS object explorer, under the server you want to modify, expand Security > Logins, then double-click the appropriate user which will bring up the "Login Properties" dialog.

Select User Mapping, which will show all databases on the server, with the ones having an existing mapping selected. From here you can select additional databases (and be sure to select which roles in each database that user should belong to), then click OK to add the mappings.

enter image description here

These mappings can become disconnected after a restore or similar operation. In this case, the user may still exist in the database but is not actually mapped to a login. If that happens, you can run the following to restore the login:

USE {database};
ALTER USER {user} WITH login = {login}

You can also delete the DB user and recreate it from the Login Properties dialog, but any role memberships or other settings would need to be recreated.

Updating .class file in jar

Simply drag and drop your new class file to the JAR using 7-Zip or Winzip. You can even modify a JAR file that is included in a WAR file using the parent folder icon, and click Ok when 7zip detects that the inside file has been modified

How can I verify if an AD account is locked?

If you want to check via command line , then use command "net user username /DOMAIN"

enter image description here

Modulo operator in Python

you should use fmod(a,b)

While abs(x%y) < abs(y) is true mathematically, for floats it may not be true numerically due to roundoff.

For example, and assuming a platform on which a Python float is an IEEE 754 double-precision number, in order that -1e-100 % 1e100 have the same sign as 1e100, the computed result is -1e-100 + 1e100, which is numerically exactly equal to 1e100.

Function fmod() in the math module returns a result whose sign matches the sign of the first argument instead, and so returns -1e-100 in this case. Which approach is more appropriate depends on the application.

where x = a%b is used for integer modulo

Populating a dictionary using for loops (python)

>>> dict(zip(keys, values))
{0: 'Hi', 1: 'I', 2: 'am', 3: 'John'}

How to Automatically Close Alerts using Twitter Bootstrap

I had this same issue when trying to handle popping alerts and fading them. I searched around various places and found this to be my solution. Adding and removing the 'in' class fixed my issue.

window.setTimeout(function() { // hide alert message
    $("#alert_message").removeClass('in'); 

}, 5000);

When using .remove() and similarly the .alert('close') solution I seemed to hit an issue with the alert being removed from the document, so if I wanted to use the same alert div again I was unable to. This solution means the alert is reusable without refreshing the page. (I was using aJax to submit a form and present feedback to the user)

    $('#Some_Button_Or_Event_Here').click(function () { // Show alert message
        $('#alert_message').addClass('in'); 
    });

How to call Stored Procedure in a View?

Easiest solution that I might have found is to create a table from the data you get from the SP. Then create a view from that:

Insert this at the last step when selecting data from the SP. SELECT * into table1 FROM #Temp

create view vw_view1 as select * from table1

Retrieving the first digit of a number

Integer.parseInt will take a string and return a int.

CSS: borders between table columns only

There's no easy way of doing this, other than doing something like class="lastCell" on the last td in each tr, and then setting your css up like this:

#table td {
    border-right: 5px solid red
}

.lastCell {
    border-right: none;
}

PackagesNotFoundError: The following packages are not available from current channels:

Even i was facing the same problem ,but solved it by

conda install -c conda-forge pysoundfile

while importing it

import soundfile 

How do you save/store objects in SharedPreferences on Android?

So many good answers, her are my 2 cents

i prefer to use inline function and old style of put and get value

object PreferenceHelper {

    private const val PREFERENCES_KEY = "MyLocalPreference"

    private fun getPreference(context: Context): SharedPreferences {
        return context.getSharedPreferences(
            PREFERENCES_KEY,
            Context.MODE_PRIVATE
        )
    }

    fun setBoolean(appContext: Context, key: String?, value: Boolean?) =
        getPreference(appContext).edit().putBoolean(key, value!!).apply()

    fun setInteger(appContext: Context, key: String?, value: Int) =
        getPreference(appContext).edit().putInt(key, value).apply()

    fun setFloat(appContext: Context, key: String?, value: Float) =
        getPreference(appContext).edit().putFloat(key, value).apply()

    fun setString(appContext: Context, key: String?, value: String?) =
        getPreference(appContext).edit().putString(key, value).apply()

    // To retrieve values from shared preferences:
    fun getBoolean(appContext: Context, key: String?, defaultValue: Boolean?): Boolean =
        getPreference(appContext).getBoolean(key, defaultValue!!)

    fun getInteger(appContext: Context, key: String?, defaultValue: Int): Int =
        getPreference(appContext)
            .getInt(key, defaultValue)

    fun getString(appContext: Context, key: String?, defaultValue: String?): String? =
        getPreference(appContext)
            .getString(key, defaultValue)


}

Usage

PreferenceHelper.setString(context,"CUSTOMER_NAME", "HITESH")

Toast.makeText(context, "Hello " + PreferenceHelper.getString(context,"CUSTOMER_NAME", "User"), Toast.LENGTH_LONG).show()

multiple figure in latex with captions

Look at the Subfloats section of http://en.wikibooks.org/wiki/LaTeX/Floats,_Figures_and_Captions.

\begin{figure}[htp]
  \centering
  \label{figur}\caption{equation...}

  \subfloat[Subcaption 1]{\label{figur:1}\includegraphics[width=60mm]{explicit3185.eps}}
  \subfloat[Subcaption 2]{\label{figur:2}\includegraphics[width=60mm]{explicit3183.eps}}
  \\
  \subfloat[Subcaption 3]{\label{figur:3}\includegraphics[width=60mm]{explicit1501.eps}}
  \subfloat[Subcaption 4]{\label{figur:4}\includegraphics[width=60mm]{explicit23185.eps}}
  \\
  \subfloat[Subcaption 5]{\label{figur:5}\includegraphics[width=60mm]{explicit23183.eps}}
  \subfloat[Subcaption 6]{\label{figur:6}\includegraphics[width=60mm]{explicit21501.eps}}

\end{figure}

Error parsing XHTML: The content of elements must consist of well-formed character data or markup

Sometimes you will need this :

 /*<![CDATA[*/
 /*]]>*/

and not only this :

 <![CDATA[
 ]]>

Difference between dangling pointer and memory leak

Pointer helps to create user defined scope to a variable, which is called Dynamic variable. Dynamic Variable can be single variable or group of variable of same type (array) or group of variable of different types (struct). Default local variable scope starts when control enters into a function and ends when control comes out of that function. Default global vairable scope starts at program execution and ends once program finishes.

But scope of a dynamic variable which holds by a pointer can start and end at any point in a program execution, which has to be decided by a programmer. Dangling and memory leak comes into picture only if a programmer doesnt handle the end of scope.

Memory leak will occur if a programmer, doesnt write the code (free of pointer) for end of scope for dynamic variables. Any way once program exits complete process memory will be freed, at that time this leaked memory also will get freed. But it will cause a very serious problem for a process which is running long time.

Once scope of dynamic variable comes to end(freed), NULL should be assigned to pointer variable. Otherwise if the code wrongly accesses it undefined behaviour will happen. So dangling pointer is nothing but a pointer which is pointing a dynamic variable whose scope is already finished.

What does "select count(1) from table_name" on any database tables mean?

Difference between count(*) and count(1) in oracle?

count(*) means it will count all records i.e each and every cell BUT

count(1) means it will add one pseudo column with value 1 and returns count of all records

In Bootstrap open Enlarge image in modal

css:

img.modal-img {
  cursor: pointer;
  transition: 0.3s;
}
img.modal-img:hover {
  opacity: 0.7;
}
.img-modal {
  display: none;
  position: fixed;
  z-index: 99999;
  padding-top: 100px;
  left: 0;
  top: 0;
  width: 100%;
  height: 100%;
  overflow: auto;
  background-color: rgba(0,0,0,0.9);
}
.img-modal img {
  margin: auto;
  display: block;
  width: 80%;
  max-width: 700%;
}
.img-modal div {
  margin: auto;
  display: block;
  width: 80%;
  max-width: 700px;
  text-align: center;
  color: #ccc;
  padding: 10px 0;
  height: 150px;
}
.img-modal img, .img-modal div {
  animation: zoom 0.6s;
}
.img-modal span {
  position: absolute;
  top: 15px;
  right: 35px;
  color: #f1f1f1;
  font-size: 40px;
  font-weight: bold;
  transition: 0.3s;
  cursor: pointer;
}
@media only screen and (max-width: 700px) {
  .img-modal img {
    width: 100%;
  }
}
@keyframes zoom {
  0% {
    transform: scale(0);
  }
  100% {
    transform: scale(1);
  }
}

Javascript:

_x000D_
_x000D_
$('img.modal-img').each(function() {_x000D_
    var modal = $('<div class="img-modal"><span>&times;</span><img /><div></div></div>');_x000D_
    modal.find('img').attr('src', $(this).attr('src'));_x000D_
    if($(this).attr('alt'))_x000D_
      modal.find('div').text($(this).attr('alt'));_x000D_
    $(this).after(modal);_x000D_
    modal = $(this).next();_x000D_
    $(this).click(function(event) {_x000D_
      modal.show(300);_x000D_
      modal.find('span').show(0.3);_x000D_
    });_x000D_
    modal.find('span').click(function(event) {_x000D_
      modal.hide(300);_x000D_
    });_x000D_
  });_x000D_
  $(document).keyup(function(event) {_x000D_
    if(event.which==27)_x000D_
      $('.img-modal>span').click();_x000D_
  });
_x000D_
img.modal-img {_x000D_
  cursor: pointer;_x000D_
  transition: 0.3s;_x000D_
}_x000D_
img.modal-img:hover {_x000D_
  opacity: 0.7;_x000D_
}_x000D_
.img-modal {_x000D_
  display: none;_x000D_
  position: fixed;_x000D_
  z-index: 99999;_x000D_
  padding-top: 100px;_x000D_
  left: 0;_x000D_
  top: 0;_x000D_
  width: 100%;_x000D_
  height: 100%;_x000D_
  overflow: auto;_x000D_
  background-color: rgba(0,0,0,0.9);_x000D_
}_x000D_
.img-modal img {_x000D_
  margin: auto;_x000D_
  display: block;_x000D_
  width: 80%;_x000D_
  max-width: 700%;_x000D_
}_x000D_
.img-modal div {_x000D_
  margin: auto;_x000D_
  display: block;_x000D_
  width: 80%;_x000D_
  max-width: 700px;_x000D_
  text-align: center;_x000D_
  color: #ccc;_x000D_
  padding: 10px 0;_x000D_
  height: 150px;_x000D_
}_x000D_
.img-modal img, .img-modal div {_x000D_
  animation: zoom 0.6s;_x000D_
}_x000D_
.img-modal span {_x000D_
  position: absolute;_x000D_
  top: 15px;_x000D_
  right: 35px;_x000D_
  color: #f1f1f1;_x000D_
  font-size: 40px;_x000D_
  font-weight: bold;_x000D_
  transition: 0.3s;_x000D_
  cursor: pointer;_x000D_
}_x000D_
@media only screen and (max-width: 700px) {_x000D_
  .img-modal img {_x000D_
    width: 100%;_x000D_
  }_x000D_
}_x000D_
@keyframes zoom {_x000D_
  0% {_x000D_
    transform: scale(0);_x000D_
  }_x000D_
  100% {_x000D_
    transform: scale(1);_x000D_
  }_x000D_
}_x000D_
Javascript:_x000D_
_x000D_
$('img.modal-img').each(function() {_x000D_
    var modal = $('<div class="img-modal"><span>&times;</span><img /><div></div></div>');_x000D_
    modal.find('img').attr('src', $(this).attr('src'));_x000D_
    if($(this).attr('alt'))_x000D_
      modal.find('div').text($(this).attr('alt'));_x000D_
    $(this).after(modal);_x000D_
    modal = $(this).next();_x000D_
    $(this).click(function(event) {_x000D_
      modal.show(300);_x000D_
      modal.find('span').show(0.3);_x000D_
    });_x000D_
    modal.find('span').click(function(event) {_x000D_
      modal.hide(300);_x000D_
    });_x000D_
  });_x000D_
  $(document).keyup(function(event) {_x000D_
    if(event.which==27)_x000D_
      $('.img-modal>span').click();_x000D_
  });_x000D_
_x000D_
HTML:
_x000D_
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.9.1/jquery.min.js"></script>_x000D_
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/js/bootstrap.min.js"></script>_x000D_
<link href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css" rel="stylesheet"/>_x000D_
<img src="http://www.google.com/favicon.ico" class="modal-img">
_x000D_
_x000D_
_x000D_

Calculating Pearson correlation and significance in Python

You may wonder how to interpret your probability in the context of looking for a correlation in a particular direction (negative or positive correlation.) Here is a function I wrote to help with that. It might even be right!

It's based on info I gleaned from http://www.vassarstats.net/rsig.html and http://en.wikipedia.org/wiki/Student%27s_t_distribution, thanks to other answers posted here.

# Given (possibly random) variables, X and Y, and a correlation direction,
# returns:
#  (r, p),
# where r is the Pearson correlation coefficient, and p is the probability
# that there is no correlation in the given direction.
#
# direction:
#  if positive, p is the probability that there is no positive correlation in
#    the population sampled by X and Y
#  if negative, p is the probability that there is no negative correlation
#  if 0, p is the probability that there is no correlation in either direction
def probabilityNotCorrelated(X, Y, direction=0):
    x = len(X)
    if x != len(Y):
        raise ValueError("variables not same len: " + str(x) + ", and " + \
                         str(len(Y)))
    if x < 6:
        raise ValueError("must have at least 6 samples, but have " + str(x))
    (corr, prb_2_tail) = stats.pearsonr(X, Y)

    if not direction:
        return (corr, prb_2_tail)

    prb_1_tail = prb_2_tail / 2
    if corr * direction > 0:
        return (corr, prb_1_tail)

    return (corr, 1 - prb_1_tail)

Sorting options elements alphabetically using jQuery

Yes you can sort the options by its text and append it back to the select box.

 function NASort(a, b) {    
      if (a.innerHTML == 'NA') {
          return 1;   
      }
      else if (b.innerHTML == 'NA') {
          return -1;   
      }       
      return (a.innerHTML > b.innerHTML) ? 1 : -1;
  };

Fiddle: https://jsfiddle.net/vaishali_ravisankar/5zfohf6v/

How to read data from excel file using c#

Save the Excel file to CSV, and read the resulting file with C# using a CSV reader library like FileHelpers.

Get the current first responder without using a private API

For a Swift 3 & 4 version of nevyn's answer:

UIApplication.shared.sendAction(#selector(UIView.resignFirstResponder), to: nil, from: nil, for: nil)

How does ApplicationContextAware work in Spring?

Spring source code to explain how ApplicationContextAware work
when you use ApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml");
In AbstractApplicationContext class,the refresh() method have the following code:

// Prepare the bean factory for use in this context.
prepareBeanFactory(beanFactory);

enter this method,beanFactory.addBeanPostProcessor(new ApplicationContextAwareProcessor(this)); will add ApplicationContextAwareProcessor to AbstractrBeanFactory.

protected void prepareBeanFactory(ConfigurableListableBeanFactory beanFactory) {
        // Tell the internal bean factory to use the context's class loader etc.
        beanFactory.setBeanClassLoader(getClassLoader());
        beanFactory.setBeanExpressionResolver(new StandardBeanExpressionResolver(beanFactory.getBeanClassLoader()));
        beanFactory.addPropertyEditorRegistrar(new ResourceEditorRegistrar(this, getEnvironment()));
        // Configure the bean factory with context callbacks.
        beanFactory.addBeanPostProcessor(new ApplicationContextAwareProcessor(this));
...........

When spring initialize bean in AbstractAutowireCapableBeanFactory, in method initializeBean,call applyBeanPostProcessorsBeforeInitialization to implement the bean post process. the process include inject the applicationContext.

@Override
    public Object applyBeanPostProcessorsBeforeInitialization(Object existingBean, String beanName)
            throws BeansException {
        Object result = existingBean;
        for (BeanPostProcessor beanProcessor : getBeanPostProcessors()) {
            result = beanProcessor.postProcessBeforeInitialization(result, beanName);
            if (result == null) {
                return result;
            }
        }
        return result;
    }

when BeanPostProcessor implement Objectto execute the postProcessBeforeInitialization method,for example ApplicationContextAwareProcessor that added before.

private void invokeAwareInterfaces(Object bean) {
        if (bean instanceof Aware) {
            if (bean instanceof EnvironmentAware) {
                ((EnvironmentAware) bean).setEnvironment(this.applicationContext.getEnvironment());
            }
            if (bean instanceof EmbeddedValueResolverAware) {
                ((EmbeddedValueResolverAware) bean).setEmbeddedValueResolver(
                        new EmbeddedValueResolver(this.applicationContext.getBeanFactory()));
            }
            if (bean instanceof ResourceLoaderAware) {
                ((ResourceLoaderAware) bean).setResourceLoader(this.applicationContext);
            }
            if (bean instanceof ApplicationEventPublisherAware) {
                ((ApplicationEventPublisherAware) bean).setApplicationEventPublisher(this.applicationContext);
            }
            if (bean instanceof MessageSourceAware) {
                ((MessageSourceAware) bean).setMessageSource(this.applicationContext);
            }
            if (bean instanceof ApplicationContextAware) {
                ((ApplicationContextAware) bean).setApplicationContext(this.applicationContext);
            }
        }
    }

Get gateway ip address in android

Install terminal emulator app, then to see routing table run iproute from the command prompt. Does not require root permissions. I don't know how to get the DNS server. There's no /etc/resolv.conf file. You can try nslookup www.google.com and see what it reports for your server, but on my phone it reports 0.0.0.0 which isn't too helpful.

Full-screen iframe with a height of 100%

<iframe src="http://youraddress.com" style="width: 100%; height: 100vh;">

</iframe>

Checking if a date is valid in javascript

Try this:

var date = new Date();
console.log(date instanceof Date && !isNaN(date.valueOf()));

This should return true.

UPDATED: Added isNaN check to handle the case commented by Julian H. Lam

How to dynamically allocate memory space for a string and get that string from user?

realloc is a pretty expensive action... here's my way of receiving a string, the realloc ratio is not 1:1 :

char* getAString()
{    
    //define two indexes, one for logical size, other for physical
    int logSize = 0, phySize = 1;  
    char *res, c;

    res = (char *)malloc(sizeof(char));

    //get a char from user, first time outside the loop
    c = getchar();

    //define the condition to stop receiving data
    while(c != '\n')
    {
        if(logSize == phySize)
        {
            phySize *= 2;
            res = (char *)realloc(res, sizeof(char) * phySize);
        }
        res[logSize++] = c;
        c = getchar();
    }
    //here we diminish string to actual logical size, plus one for \0
    res = (char *)realloc(res, sizeof(char *) * (logSize + 1));
    res[logSize] = '\0';
    return res;
}

How to get query string parameter from MVC Razor markup?

Noneof the answers worked for me, I was getting "'HttpRequestBase' does not contain a definition for 'Query'", but this did work:

HttpContext.Current.Request.QueryString["index"]

Linq to Entities - SQL "IN" clause

I will go for Inner Join in this context. If I would have used contains, it would iterate 6 times despite if the fact that there are just one match.

var desiredNames = new[] { "Pankaj", "Garg" }; 

var people = new[]  
{  
    new { FirstName="Pankaj", Surname="Garg" },  
    new { FirstName="Marc", Surname="Gravell" },  
    new { FirstName="Jeff", Surname="Atwood" }  
}; 

var records = (from p in people join filtered in desiredNames on p.FirstName equals filtered  select p.FirstName).ToList(); 

Disadvantages of Contains

Suppose I have two list objects.

List 1      List 2
  1           12
  2            7
  3            8
  4           98
  5            9
  6           10
  7            6

Using Contains, it will search for each List 1 item in List 2 that means iteration will happen 49 times !!!

numpy get index where value is true

You can use nonzero function. it returns the nonzero indices of the given input.

Easy Way

>>> (e > 15).nonzero()

(array([1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2]), array([6, 7, 8, 9, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9]))

to see the indices more cleaner, use transpose method:

>>> numpy.transpose((e>15).nonzero())

[[1 6]
 [1 7]
 [1 8]
 [1 9]
 [2 0]
 ...

Not Bad Way

>>> numpy.nonzero(e > 15)

(array([1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2]), array([6, 7, 8, 9, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9]))

or the clean way:

>>> numpy.transpose(numpy.nonzero(e > 15))

[[1 6]
 [1 7]
 [1 8]
 [1 9]
 [2 0]
 ...

What is the best way to auto-generate INSERT statements for a SQL Server table?

You can generate INSERT or MERGE statement with this simple and free application I wrote a few years ago:
Data Script Writer (Desktop Application for Windows)

enter image description here Also, I wrote a blog post about these tools recently and approach to leveraging SSDT for a deployment database with data. Find out more:
Script and deploy the data for database from SSDT project

How to run script as another user without password?

Call visudo and add this:

user1 ALL=(user2) NOPASSWD: /home/user2/bin/test.sh

The command paths must be absolute! Then call sudo -u user2 /home/user2/bin/test.sh from a user1 shell. Done.

Disable all table constraints in Oracle

This is another way for disabling constraints (it came from https://asktom.oracle.com/pls/asktom/f?p=100:11:2402577774283132::::P11_QUESTION_ID:399218963817)

WITH qry0 AS
       (SELECT    'ALTER TABLE '
               || child_tname
               || ' DISABLE CONSTRAINT '
               || child_cons_name
                 disable_fk
              ,   'ALTER TABLE '
               || parent_tname
               || ' DISABLE CONSTRAINT '
               || parent.parent_cons_name
                 disable_pk
          FROM (SELECT a.table_name child_tname
                      ,a.constraint_name child_cons_name
                      ,b.r_constraint_name parent_cons_name
                      ,LISTAGG ( column_name, ',') WITHIN GROUP (ORDER BY position) child_columns
                  FROM user_cons_columns a
                      ,user_constraints b
                 WHERE a.constraint_name = b.constraint_name AND b.constraint_type = 'R'
                GROUP BY a.table_name, a.constraint_name
                        ,b.r_constraint_name) child
              ,(SELECT a.constraint_name parent_cons_name
                      ,a.table_name parent_tname
                      ,LISTAGG ( column_name, ',') WITHIN GROUP (ORDER BY position) parent_columns
                  FROM user_cons_columns a
                      ,user_constraints b
                 WHERE a.constraint_name = b.constraint_name AND b.constraint_type IN ('P', 'U')
                GROUP BY a.table_name, a.constraint_name) parent
         WHERE child.parent_cons_name = parent.parent_cons_name
           AND (parent.parent_tname LIKE 'V2_%' OR child.child_tname LIKE 'V2_%'))
SELECT DISTINCT disable_pk
  FROM qry0
UNION
SELECT DISTINCT disable_fk
  FROM qry0;

works like a charm

What is Linux’s native GUI API?

The closest thing to Win32 in linux would be the libc, as you mention not only the UI but events and "other os stuff"

Meaning of Open hashing and Closed hashing

You have an array that is the "hash table".

In Open Hashing each cell in the array points to a list containg the collisions. The hashing has produced the same index for all items in the linked list.

In Closed Hashing you use only one array for everything. You store the collisions in the same array. The trick is to use some smart way to jump from collision to collision unitl you find what you want. And do this in a reproducible / deterministic way.

Django - taking values from POST request

Read about request objects that your views receive: https://docs.djangoproject.com/en/dev/ref/request-response/#httprequest-objects

Also your hidden field needs a reliable name and then a value:

<input type="hidden" name="title" value="{{ source.title }}">

Then in a view:

request.POST.get("title", "")

Can I try/catch a warning?

Combining these lines of code around a file_get_contents() call to an external url helped me handle warnings like "failed to open stream: Connection timed out" much better:

set_error_handler(function ($err_severity, $err_msg, $err_file, $err_line, array $err_context)
{
    throw new ErrorException( $err_msg, 0, $err_severity, $err_file, $err_line );
}, E_WARNING);
try {
    $iResult = file_get_contents($sUrl);
} catch (Exception $e) {
    $this->sErrorMsg = $e->getMessage();
}
restore_error_handler();

This solution works within object context, too. You could use it in a function:

public function myContentGetter($sUrl)
{
  ... code above ...
  return $iResult;
}

JQuery addclass to selected div, remove class if another div is selected

You can use a single line to add and remove class on a div. Please remove a class first to add a new class.

$('div').on('click',function(){
  $('div').removeClass('active').addClass('active');     
});

How to export a Hive table into a CSV file?

Below is the end-to-end solution that I use to export Hive table data to HDFS as a single named CSV file with a header.
(it is unfortunate that it's not possible to do with one HQL statement)
It consists of several commands, but it's quite intuitive, I think, and it does not rely on the internal representation of Hive tables, which may change from time to time.
Replace "DIRECTORY" with "LOCAL DIRECTORY" if you want to export the data to a local filesystem versus HDFS.

# cleanup the existing target HDFS directory, if it exists
sudo -u hdfs hdfs dfs -rm -f -r /tmp/data/my_exported_table_name/*

# export the data using Beeline CLI (it will create a data file with a surrogate name in the target HDFS directory)
beeline -u jdbc:hive2://my_hostname:10000 -n hive -e "INSERT OVERWRITE DIRECTORY '/tmp/data/my_exported_table_name' ROW FORMAT DELIMITED FIELDS TERMINATED BY ',' SELECT * FROM my_exported_table_name"

# set the owner of the target HDFS directory to whatever UID you'll be using to run the subsequent commands (root in this case)
sudo -u hdfs hdfs dfs -chown -R root:hdfs /tmp/data/my_exported_table_name

# write the CSV header record to a separate file (make sure that its name is higher in the sort order than for the data file in the target HDFS directory)
# also, obviously, make sure that the number and the order of fields is the same as in the data file
echo 'field_name_1,field_name_2,field_name_3,field_name_4,field_name_5' | hadoop fs -put - /tmp/data/my_exported_table_name/.header.csv

# concatenate all (2) files in the target HDFS directory into the final CSV data file with a header
# (this is where the sort order of the file names is important)
hadoop fs -cat /tmp/data/my_exported_table_name/* | hadoop fs -put - /tmp/data/my_exported_table_name/my_exported_table_name.csv

# give the permissions for the exported data to other users as necessary
sudo -u hdfs hdfs dfs -chmod -R 777 /tmp/data/hive_extr/drivers

Get the second highest value in a MySQL table

SELECT username, salary
FROM tblname
GROUP by salary
ORDER by salary desc
LIMIT 0,1 ;

C++ [Error] no matching function for call to

You are trying to call DeckOfCards::shuffle with a deckOfCards parameter:

deckOfCards cardDeck; // create DeckOfCards object
cardDeck.shuffle(cardDeck); // shuffle the cards in the deck

But the method takes a vector<Card>&:

void deckOfCards::shuffle(vector<Card>& deck)

The compiler error messages are quite clear on this. I'll paraphrase the compiler as it talks to you.

Error:

[Error] no matching function for call to 'deckOfCards::shuffle(deckOfCards&)'

Paraphrased:

Hey, pal. You're trying to call a function called shuffle which apparently takes a single parameter of type reference-to-deckOfCards, but there is no such function.

Error:

[Note] candidate is:

In file included from main.cpp

[Note] void deckOfCards::shuffle(std::vector&)

Paraphrased:

I mean, maybe you meant this other function called shuffle, but that one takes a reference-tovector<something>.

Error:

[Note] no known conversion for argument 1 from 'deckOfCards' to 'std::vector&'

Which I'd be happy to call if I knew how to convert from a deckOfCards to a vector; but I don't. So I won't.

How can I keep a container running on Kubernetes?

  1. In your Dockerfile use this command:

    CMD ["sh", "-c", "tail -f /dev/null"]
    
  2. Build your docker image.

  3. Push it to your cluster or similar, just to make sure the image it's available.
  4. kubectl run debug-container -it --image=<your-image>
    

env: node: No such file or directory in mac

I got such a problem after I upgraded my node version with brew. To fix the problem

1)run $brew doctor to check out if it is successfully installed or not 2) In case you missed clearing any node-related file before, such error log might pop up:

Warning: You have unlinked kegs in your Cellar Leaving kegs unlinked can lead to build-trouble and cause brews that depend on those kegs to fail to run properly once built. node

3) Now you are recommended to run brew link command to delete the original node-related files and overwrite new files - $ brew link node.

And that's it - everything works again !!!

How to match, but not capture, part of a regex?

Update: Thanks to Germán Rodríguez Herrera!

In javascript try: /123-(apple(?=-)|banana(?=-)|(?!-))-?456/

Remember that the result is in group 1

Debuggex Demo

back button callback in navigationController in iOS

If you're using a Storyboard and you're coming from a push segue, you could also just override shouldPerformSegueWithIdentifier:sender:.

Is there a Public FTP server to test upload and download?

There's lots of FTP sites you can get into with the 'anonymous' account and download, but a 'public' site that allows anonymous uploads would be utterly swamped with pr0n and warez in short order.

It's easy enough to set up your own FTP server for testing uploads. There's plenty of them for most any desktop OS. There's one built into IIS, for instance.

Merge trunk to branch in Subversion

Last revision merged from trunk to branch can be found by running this command inside the working copy directory:

svn log -v --stop-on-copy

Is there a way to ignore a single FindBugs warning?

The FindBugs initial approach involves XML configuration files aka filters. This is really less convenient than the PMD solution but FindBugs works on bytecode, not on the source code, so comments are obviously not an option. Example:

<Match>
   <Class name="com.mycompany.Foo" />
   <Method name="bar" />
   <Bug pattern="DLS_DEAD_STORE_OF_CLASS_LITERAL" />
</Match>

However, to solve this issue, FindBugs later introduced another solution based on annotations (see SuppressFBWarnings) that you can use at the class or at the method level (more convenient than XML in my opinion). Example (maybe not the best one but, well, it's just an example):

@edu.umd.cs.findbugs.annotations.SuppressFBWarnings(
    value="HE_EQUALS_USE_HASHCODE", 
    justification="I know what I'm doing")

Note that since FindBugs 3.0.0 SuppressWarnings has been deprecated in favor of @SuppressFBWarnings because of the name clash with Java's SuppressWarnings.

Deserialize a json string to an object in python

Another way is to simply pass the json string as a dict to the constructor of your object. For example your object is:

class Payload(object):
    def __init__(self, action, method, data, *args, **kwargs):
        self.action = action
        self.method = method
        self.data = data

And the following two lines of python code will construct it:

j = json.loads(yourJsonString)
payload = Payload(**j)

Basically, we first create a generic json object from the json string. Then, we pass the generic json object as a dict to the constructor of the Payload class. The constructor of Payload class interprets the dict as keyword arguments and sets all the appropriate fields.

Find and replace with a newline in Visual Studio Code

In version 1.1.1:

  • Ctrl+H
  • Check the regular exp icon .*
  • Search: ><
  • Replace: >\n<

Is there a way to retrieve the view definition from a SQL Server using plain ADO?

For users of SQL 2000, the actual command that will provide this information is:

select c.text
from sysobjects     o
join syscomments    c on c.id = o.id
where o.name = '<view_name_here>'
  and o.type      = 'V'

Html.BeginForm and adding properties

You can also use the following syntax for the strongly typed version:

<% using (Html.BeginForm<SomeController>(x=> x.SomeAction(), 
          FormMethod.Post, 
          new { enctype = "multipart/form-data" })) 
   { %>

Error HRESULT E_FAIL has been returned from a call to a COM component VS2012 when debugging

Maybe this page helps:

Scenario Two: The Microsoft Visual Studio 2010 IDE crashes while creating OR debugging a web application project. This above error occurs because of corrupted Cache of Visual Studio 2010. In order to resolve the issue just delete the project Cache from the below location:

C:\Program Files\Microsoft Visual Studio 10.0\Common7\IDE\ProjectTemplatesCache

C:\Program Files(x86)\Microsoft Visual Studio 10.0\Common7\IDE\ProjectTemplatesCache

Then run devenv.exe /setup to re-build the cache.

How to declare a global variable in php?

This answer is very late but what I do is set a class that holds Booleans, arrays, and integer-initial values as global scope static variables. Any constant strings are defined as such.

define("myconstant", "value"); 

class globalVars {

    static $a = false;

    static $b = 0;

    static $c = array('first' => 2, 'second' => 5);

}


function test($num) {

    if (!globalVars::$a) {

        $returnVal = 'The ' . myconstant . ' of ' . $num . ' plus ' . globalVars::$b . ' plus ' . globalVars::$c['second'] . ' is ' . ($num + globalVars::$b + globalVars::$c['second']) . '.';

        globalVars::$a = true;

    } else {

        $returnVal = 'I forgot';

    }

    return $returnVal;

}

echo test(9); ---> The value of 9 + 0 + 5 is 14.

echo "<br>";

echo globalVars::$a; ----> 1

The static keywords must be present in the class else the vars $a, $b, and $c will not be globally scoped.

Count items in a folder with PowerShell

If you need to speed up the process (for example counting 30k or more files) then I would go with something like this..

$filepath = "c:\MyFolder"
$filetype = "*.txt"
$file_count = [System.IO.Directory]::GetFiles("$filepath", "$filetype").Count

event.returnValue is deprecated. Please use the standard event.preventDefault() instead

This is only a warning: your code still works, but probably won't work in the future as the method is deprecated. See the relevant source of Chromium and corresponding patch.

This has already been recognised and fixed in jQuery 1.11 (see here and here).

Remove All Event Listeners of Specific Type

I know this is old, but I had a similar issue with no real answers, where I wanted to remove all keydown event listeners from the document. Instead of removing them, I override the addEventListener to ignore them before they were even added, similar to Toms answer above, by adding this before any other scripts are loaded:

<script type="text/javascript">
    var current = document.addEventListener;
    document.addEventListener = function (type, listener) {
        if(type =="keydown")
        {
            //do nothing
        }
        else
        {
            var args = [];
            args[0] = type;
            args[1] = listener;
            current.apply(this, args);
        }
    };
</script>

"Please provide a valid cache path" error in laravel

Ensure the below folders in storage directory:

  • logs
  • framework
  • framework/cache
  • framework/cache/data
  • framework/sessions
  • framework/testing
  • framework/views

Below is a command-line snippet that does for you

cd storage
mkdir logs
mkdir framework
mkdir framework/cache && framework/cache/data
mkdir framework/sessions
mkdir framework/testing
mkdir framework/views
chgrp -R www-data ../storage
chown -R www-data ../storage

What is JNDI? What is its basic use? When is it used?

What is JNDI ?

It stands for Java Naming and Directory Interface.

What is its basic use?

JNDI allows distributed applications to look up services in an abstract, resource-independent way.

When it is used?

The most common use case is to set up a database connection pool on a Java EE application server. Any application that's deployed on that server can gain access to the connections they need using the JNDI name java:comp/env/FooBarPool without having to know the details about the connection.

This has several advantages:

  1. If you have a deployment sequence where apps move from devl->int->test->prod environments, you can use the same JNDI name in each environment and hide the actual database being used. Applications don't have to change as they migrate between environments.
  2. You can minimize the number of folks who need to know the credentials for accessing a production database. Only the Java EE app server needs to know if you use JNDI.

How can I find the first occurrence of a sub-string in a python string?

Quick Overview: index and find

Next to the find method there is as well index. find and index both yield the same result: returning the position of the first occurrence, but if nothing is found index will raise a ValueError whereas find returns -1. Speedwise, both have the same benchmark results.

s.find(t)    #returns: -1, or index where t starts in s
s.index(t)   #returns: Same as find, but raises ValueError if t is not in s

Additional knowledge: rfind and rindex:

In general, find and index return the smallest index where the passed-in string starts, and rfind and rindex return the largest index where it starts Most of the string searching algorithms search from left to right, so functions starting with r indicate that the search happens from right to left.

So in case that the likelihood of the element you are searching is close to the end than to the start of the list, rfind or rindex would be faster.

s.rfind(t)   #returns: Same as find, but searched right to left
s.rindex(t)  #returns: Same as index, but searches right to left

Source: Python: Visual QuickStart Guide, Toby Donaldson

What is the use of "assert"?

If you ever want to know exactly what a reserved function does in python, type in help(enter_keyword)

Make sure if you are entering a reserved keyword that you enter it as a string.

How to update record using Entity Framework 6?

I have the same problem when trying to update record using Attach() and then SaveChanges() combination, but I am using SQLite DB and its EF provider (the same code works in SQLServer DB without problem).

I found out, when your DB column has GUID (or UniqueIdentity) in SQLite and your model is nvarchar, SQLIte EF treats it as Binary(i.e., byte[]) by default. So when SQLite EF provider tries to convert GUID into the model (string in my case) it will fail as it will convert to byte[]. The fix is to tell the SQLite EF to treat GUID as TEXT (and therefore conversion is into strings, not byte[]) by defining "BinaryGUID=false;" in the connectionstring (or metadata, if you're using database first) like so:

  <connectionStrings>
    <add name="Entities" connectionString="metadata=res://savetyping...=System.Data.SQLite.EF6;provider connection string=&quot;data source=C:\...\db.sqlite3;Version=3;BinaryGUID=false;App=EntityFramework&quot;" providerName="System.Data.EntityClient" />
  </connectionStrings>

Link to the solution that worked for me: How does the SQLite Entity Framework 6 provider handle Guids?

Android: How to bind spinner to custom object list?

Here's the complete process in Kotlin:

the spinner adapter class:

class CustomSpinnerAdapter(
    context: Context,
    textViewResourceId: Int,
    val list: List<User>
) : ArrayAdapter<User>(
    context,
    textViewResourceId,
    list
) {
    override fun getCount() = list.size

    override fun getItem(position: Int) = list[position]

    override fun getItemId(position: Int) = list[position].report.toLong()

    override fun getView(position: Int, convertView: View?, parent: ViewGroup): View {
        return (super.getDropDownView(position, convertView, parent) as TextView).apply {
            text = list[position].name
        }
    }

    override fun getDropDownView(position: Int, convertView: View?, parent: ViewGroup): View {
        return (super.getDropDownView(position, convertView, parent) as TextView).apply {
            text = list[position].name
        }
    }
}

and use it in your activity/fragment like this:

spinner.adapter = CustomerSalesSpinnerAdapter(
            context,
            R.layout.cuser_spinner_item,
            userList
        )

Is there a way to access an iteration-counter in Java's for-each loop?

The easiest solution is to just run your own counter thus:

int i = 0;
for (String s : stringArray) {
    doSomethingWith(s, i);
    i++;
}

The reason for this is because there's no actual guarantee that items in a collection (which that variant of for iterates over) even have an index, or even have a defined order (some collections may change the order when you add or remove elements).

See for example, the following code:

import java.util.*;

public class TestApp {
  public static void AddAndDump(AbstractSet<String> set, String str) {
    System.out.println("Adding [" + str + "]");
    set.add(str);
    int i = 0;
    for(String s : set) {
        System.out.println("   " + i + ": " + s);
        i++;
    }
  }

  public static void main(String[] args) {
    AbstractSet<String> coll = new HashSet<String>();
    AddAndDump(coll, "Hello");
    AddAndDump(coll, "My");
    AddAndDump(coll, "Name");
    AddAndDump(coll, "Is");
    AddAndDump(coll, "Pax");
  }
}

When you run that, you can see something like:

Adding [Hello]
   0: Hello
Adding [My]
   0: Hello
   1: My
Adding [Name]
   0: Hello
   1: My
   2: Name
Adding [Is]
   0: Hello
   1: Is
   2: My
   3: Name
Adding [Pax]
   0: Hello
   1: Pax
   2: Is
   3: My
   4: Name

indicating that, rightly so, order is not considered a salient feature of a set.

There are other ways to do it without a manual counter but it's a fair bit of work for dubious benefit.

Execute Stored Procedure from a Function

Here is another possible workaround:

if exists (select * from master..sysservers where srvname = 'loopback')
    exec sp_dropserver 'loopback'
go
exec sp_addlinkedserver @server = N'loopback', @srvproduct = N'', @provider = N'SQLOLEDB', @datasrc = @@servername
go

create function testit()
    returns int
as
begin
    declare @res int;
    select @res=count(*) from openquery(loopback, 'exec sp_who');
    return @res
end
go

select dbo.testit()

It's not so scary as xp_cmdshell but also has too many implications for practical use.

Is there a way to delete created variables, functions, etc from the memory of the interpreter?

Yes. There is a simple way to remove everything in iPython. In iPython console, just type:

%reset

Then system will ask you to confirm. Press y. If you don't want to see this prompt, simply type:

%reset -f

This should work..

Is the NOLOCK (Sql Server hint) bad practice?

In real life where you encounter systems already written and adding indexes to tables then drastically slows down the data loading of a 14gig data table, you are sometime forced to used WITH NOLOCK on your reports and end of month proessing so that the aggregate funtions (sum, count etc) do not do row, page, table locking and deteriate the overall performance. Easy to say in a new system never use WITH NOLOCK and use indexes - but adding indexes severly downgrades data loading, and when I'm then told, well, alter the code base to delete indexes, then bulk load then recreate the indexes - which is all well and good, if you are developing a new system. But Not when you have a system already in place.

Initializing data.frames()

I always just convert a matrix:

x <- as.data.frame(matrix(nrow = 100, ncol = 10))

How do I filter date range in DataTables?

Following one is working fine with moments js 2.10 and above

$.fn.dataTableExt.afnFiltering.push(
        function( settings, data, dataIndex ) {
            var min  = $('#min-date').val()
            var max  = $('#max-date').val()
            var createdAt = data[0] || 0; // Our date column in the table
            //createdAt=createdAt.split(" ");
            var startDate   = moment(min, "DD/MM/YYYY");
            var endDate     = moment(max, "DD/MM/YYYY");
            var diffDate = moment(createdAt, "DD/MM/YYYY");
            //console.log(startDate);
            if (
              (min == "" || max == "") ||
              (diffDate.isBetween(startDate, endDate))


            ) {  return true;  }
            return false;

        }
    );

What's a standard way to do a no-op in python?

If you need a function that behaves as a nop, try

nop = lambda *a, **k: None
nop()

Sometimes I do stuff like this when I'm making dependencies optional:

try:
    import foo
    bar=foo.bar
    baz=foo.baz
except:
    bar=nop
    baz=nop

# Doesn't break when foo is missing:
bar()
baz()

How to declare empty list and then add string in scala?

Per default collections in scala are immutable, so you have a + method which returns a new list with the element added to it. If you really need something like an add method you need a mutable collection, e.g. http://www.scala-lang.org/api/current/scala/collection/mutable/MutableList.html which has a += method.

FPDF utf-8 encoding (HOW-TO)

Not sure if it will do for Greek, but I had the same issue for Brazilian Portuguese characters and my solution was to use html entities. I had basically two cases:

  1. String may contain UTF-8 characters.

For these, I first encoded it to html entities with htmlentities() and then decoded them to iso-8859-1. Example:

$s = html_entity_decode(htmlentities($my_variable_text), ENT_COMPAT | ENT_HTML401, 'iso-8859-1');
  1. Fixed string with html entities:

For these, I just left htmlentities() call out. Example:

$s = html_entity_decode("Treasurer/Tr&eacute;sorier", ENT_COMPAT | ENT_HTML401, 'iso-8859-1');

Then I passed $s to FPDF, like in this example:

$pdf->Cell(100, 20, $s, 0, 0, 'L');

Note: ENT_COMPAT | ENT_HTML401 is the standard value for parameter #2, as in http://php.net/manual/en/function.html-entity-decode.php

Hope that helps.

Reference - What does this error mean in PHP?

Warning: function() expects parameter X to be boolean (or integer, string, etc)

If the wrong type of parameter is passed to a function – and PHP cannot convert it automatically – a warning is thrown. This warning identifies which parameter is the problem, and what data type is expected. The solution: change the indicated parameter to the correct data type.


For example this code:

echo substr(["foo"], 23);

Results in this output:

PHP Warning: substr() expects parameter 1 to be string, array given

How can I get the image url in a Wordpress theme?

You asked of Function but there is an easier way too. When you will upload the image, copy it's URL which is at the top right part of the window (View Screenshot) and paste it in the src='[link you copied]'. Hope this will help if someone is looking for similar problem.

How to solve “Microsoft Visual Studio (VS)” error “Unable to connect to the configured development Web server”

I solved this just now, in the system tray (bottom right) you can click ion the IIS icon and stop the current site, then it allowed me to run.

How to detect a USB drive has been plugged in?

It is easy to check for removable devices. However, there's no guarantee that it is a USB device:

var drives = DriveInfo.GetDrives()
    .Where(drive => drive.IsReady && drive.DriveType == DriveType.Removable);

This will return a list of all removable devices that are currently accessible. More information:

Get number days in a specified month using JavaScript?

Date.prototype.monthDays= function(){
    var d= new Date(this.getFullYear(), this.getMonth()+1, 0);
    return d.getDate();
}

Chrome refuses to execute an AJAX script due to wrong MIME type

In my case, I use

$.getJSON(url, function(json) { ... });

to make the request (to Flickr's API), and I got the same MIME error. Like the answer above suggested, adding the following code:

$.ajaxSetup({ dataType: "jsonp" });

Fixed the issue and I no longer see the MIME type error in Chrome's console.

How can I match multiple occurrences with a regex in JavaScript similar to PHP's preg_match_all()?

Hoisted from the comments

2020 comment: rather than using regex, we now have URLSearchParams, which does all of this for us, so no custom code, let alone regex, are necessary anymore.

Mike 'Pomax' Kamermans

Browser support is listed here https://caniuse.com/#feat=urlsearchparams


I would suggest an alternative regex, using sub-groups to capture name and value of the parameters individually and re.exec():

function getUrlParams(url) {
  var re = /(?:\?|&(?:amp;)?)([^=&#]+)(?:=?([^&#]*))/g,
      match, params = {},
      decode = function (s) {return decodeURIComponent(s.replace(/\+/g, " "));};

  if (typeof url == "undefined") url = document.location.href;

  while (match = re.exec(url)) {
    params[decode(match[1])] = decode(match[2]);
  }
  return params;
}

var result = getUrlParams("http://maps.google.de/maps?f=q&source=s_q&hl=de&geocode=&q=Frankfurt+am+Main&sll=50.106047,8.679886&sspn=0.370369,0.833588&ie=UTF8&ll=50.116616,8.680573&spn=0.35972,0.833588&z=11&iwloc=addr");

result is an object:

{
  f: "q"
  geocode: ""
  hl: "de"
  ie: "UTF8"
  iwloc: "addr"
  ll: "50.116616,8.680573"
  q: "Frankfurt am Main"
  sll: "50.106047,8.679886"
  source: "s_q"
  spn: "0.35972,0.833588"
  sspn: "0.370369,0.833588"
  z: "11"
}

The regex breaks down as follows:

(?:            # non-capturing group
  \?|&         #   "?" or "&"
  (?:amp;)?    #   (allow "&amp;", for wrongly HTML-encoded URLs)
)              # end non-capturing group
(              # group 1
  [^=&#]+      #   any character except "=", "&" or "#"; at least once
)              # end group 1 - this will be the parameter's name
(?:            # non-capturing group
  =?           #   an "=", optional
  (            #   group 2
    [^&#]*     #     any character except "&" or "#"; any number of times
  )            #   end group 2 - this will be the parameter's value
)              # end non-capturing group

Could not calculate build plan: Plugin org.apache.maven.plugins:maven-resources-plugin:2.5 or one of its dependencies could not be resolved

i faced the same issue while using eclipse kepler and maven version 3.2,

while building the project, it showed me the same error in eclipse

there are two versions (2.5 and 2.6) of plugin under

.m2/repository/org/apache/maven/plugins/maven-resources-plugin/

i removed 2.5 version then it worked for me

How to compare two columns in Excel (from different sheets) and copy values from a corresponding column if the first two columns match?

As kmcamara discovered, this is exactly the kind of problem that VLOOKUP is intended to solve, and using vlookup is arguably the simplest of the alternative ways to get the job done.

In addition to the three parameters for lookup_value, table_range to be searched, and the column_index for return values, VLOOKUP takes an optional fourth argument that the Excel documentation calls the "range_lookup".

Expanding on deathApril's explanation, if this argument is set to TRUE (or 1) or omitted, the table range must be sorted in ascending order of the values in the first column of the range for the function to return what would typically be understood to be the "correct" value. Under this default behavior, the function will return a value based upon an exact match, if one is found, or an approximate match if an exact match is not found.

If the match is approximate, the value that is returned by the function will be based on the next largest value that is less than the lookup_value. For example, if "12AT8003" were missing from the table in Sheet 1, the lookup formulas for that value in Sheet 2 would return '2', since "12AT8002" is the largest value in the lookup column of the table range that is less than "12AT8003". (VLOOKUP's default behavior makes perfect sense if, for example, the goal is to look up rates in a tax table.)

However, if the fourth argument is set to FALSE (or 0), VLOOKUP returns a looked-up value only if there is an exact match, and an error value of #N/A if there is not. It is now the usual practice to wrap an exact VLOOKUP in an IFERROR function in order to catch the no-match gracefully. Prior to the introduction of IFERROR, no matches were checked with an IF function using the VLOOKUP formula once to check whether there was a match, and once to return the actual match value.

Though initially harder to master, deusxmach1na's proposed solution is a variation on a powerful set of alternatives to VLOOKUP that can be used to return values for a column or list to the left of the lookup column, expanded to handle cases where an exact match on more than one criterion is needed, or modified to incorporate OR as well as AND match conditions among multiple criteria.

Repeating kcamara's chosen solution, the VLOOKUP formula for this problem would be:

   =VLOOKUP(A1,Sheet1!A$1:B$600,2,FALSE)

Uncaught TypeError: Cannot read property 'ownerDocument' of undefined

If you use ES6 anon functions, it will conflict with $(this)

This works:

$('.dna-list').on('click', '.card', function(e) {
  console.log($(this));
});

This doesn't work:

$('.dna-list').on('click', '.card', (e) => {
  console.log($(this));
});

How to install Java 8 on Mac

You can try this:

$ brew search jdk
$ brew cask install homebrew/cask-versions/adoptopenjdk8
$ /usr/libexec/java_home

 

Tomcat Server not starting with in 45 seconds

Open servers view, open Timeouts and set up Start

add start

Base64 Java encode and decode a string

You can use following approach:

import org.apache.commons.codec.binary.Base64;

// Encode data on your side using BASE64
byte[] bytesEncoded = Base64.encodeBase64(str.getBytes());
System.out.println("encoded value is " + new String(bytesEncoded));

// Decode data on other side, by processing encoded data
byte[] valueDecoded = Base64.decodeBase64(bytesEncoded);
System.out.println("Decoded value is " + new String(valueDecoded));

Hope this answers your doubt.

How do you get a list of the names of all files present in a directory in Node.js?

This will work and store the result in test.txt file which will be present in the same directory

  fs.readdirSync(__dirname).forEach(file => {
    fs.appendFileSync("test.txt", file+"\n", function(err){
    })
})

Algorithm to compare two images

This is just a suggestion, it might not work and I'm prepared to be called on this.

This will generate false positives, but hopefully not false negatives.

  1. Resize both of the images so that they are the same size (I assume that the ratios of widths to lengths are the same in both images).

  2. Compress a bitmap of both images with a lossless compression algorithm (e.g. gzip).

  3. Find pairs of files that have similar file sizes. For instance, you could just sort every pair of files you have by how similar the file sizes are and retrieve the top X.

As I said, this will definitely generate false positives, but hopefully not false negatives. You can implement this in five minutes, whereas the Porikil et. al. would probably require extensive work.

Sending a file over TCP sockets in Python

Put file inside while True like so

while True:
     f = open('torecv.png','wb')
     c, addr = s.accept()     # Establish connection with client.
     print 'Got connection from', addr
     print "Receiving..."
     l = c.recv(1024)
     while (l):
         print "Receiving..."
         f.write(l)
         l = c.recv(1024)
     f.close()
     print "Done Receiving"
     c.send('Thank you for connecting')
     c.close()   

D3.js: How to get the computed width and height for an arbitrary element?

For SVG elements

Using something like selection.node().getBBox() you get values like

{
    height: 5, 
    width: 5, 
    y: 50, 
    x: 20
} 

For HTML elements

Use selection.node().getBoundingClientRect()

What is float in Java?

The thing is that decimal numbers defaults to double. And since double doesn't fit into float you have to tell explicitely you intentionally define a float. So go with:

float b = 3.6f;

What is the difference between using constructor vs getInitialState in React / React Native?

The two approaches are not interchangeable. You should initialize state in the constructor when using ES6 classes, and define the getInitialState method when using React.createClass.

See the official React doc on the subject of ES6 classes.

class MyComponent extends React.Component {
  constructor(props) {
    super(props);
    this.state = { /* initial state */ };
  }
}

is equivalent to

var MyComponent = React.createClass({
  getInitialState() {
    return { /* initial state */ };
  },
});

How to press/click the button using Selenium if the button does not have the Id?

For Next button you can use xpath or cssSelector as below:

xpath for Next button: //input[@value='Next']

cssPath for Next button: input[value=Next]

Is it possible to install Xcode 10.2 on High Sierra (10.13.6)?

You don't need to run Xcode 10.2 for iOS 12.2 support. You just need access to the appropriate folder in DeviceSupport.

A possible solution is

  • Download Xcode 10.2 from a direkt link (not from App Store).
  • Rename it for example to Xcode102.
  • Put it into /Applications. It's possible to have multiple Xcode versions in the same directory.
  • Create a symbolic link in Terminal.app to have access to the 12.2 device support folder in Xcode 10.2

    ln -s /Applications/Xcode102.app/Contents/Developer/Platforms/iPhoneOS.platform/DeviceSupport/12.2\ \(16E226\) /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/DeviceSupport
    

You can move Xcode 10.2 to somewhere else but then you have to adjust the path.

Now Xcode 10.1 supports devices running iOS 12.2

How to strip HTML tags with jQuery?

Use the .text() function:

var text = $("<p> example ive got a string</P>").text();

Update: As Brilliand points out below, if the input string does not contain any tags and you are unlucky enough, it might be treated as a CSS selector. So this version is more robust:

var text = $("<div/>").html("<p> example ive got a string</P>").text();

Cannot authenticate into mongo, "auth fails"

Another possibility: When you created the user, you may have accidentally been useing a database other than admin, or other than the one you wanted. You need to set --authenticationDatabase to the database that the user was actually created under.

mongodb seems to put you in the test database by default when you open the shell, so you'd need to write --authenticationDatabase test rather than --authenticationDatabase admin if you accidentally were useing test when you ran db.createUser(...).

Assuming you have access to the machine that's running the mongodb instance, y could disable authorization in /etc/mongod.conf (comment out authorization which is nested under security), and then restart your server, and then run:

mongo
show users

And you might get something like this:

{
    "_id" : "test.myusername",
    "user" : "myusername",
    "db" : "test",
    "roles" : [
        {
            "role" : "dbOwner",
            "db" : "mydatabasename"
        }
    ],
    "mechanisms" : [
        "SCRAM-SHA-1",
        "SCRAM-SHA-256"
    ]
}

Notice that the db value equals test. That's because when I created the user, I didn't first run use admin or use desiredDatabaseName. So you can delete the user with db.dropUser("myusername") and then create another user under your desired database like so:

use desiredDatabaseName
db.createUser(...)

Hopefully that helps someone who was in my position as a noob with this stuff.

Reading data from a website using C#

The WebClient class should be more than capable of handling the functionality you describe, for example:

System.Net.WebClient wc = new System.Net.WebClient();
byte[] raw = wc.DownloadData("http://www.yoursite.com/resource/file.htm");

string webData = System.Text.Encoding.UTF8.GetString(raw);

or (further to suggestion from Fredrick in comments)

System.Net.WebClient wc = new System.Net.WebClient();
string webData = wc.DownloadString("http://www.yoursite.com/resource/file.htm");

When you say it took 30 seconds, can you expand on that a little more? There are many reasons as to why that could have happened. Slow servers, internet connections, dodgy implementation etc etc.

You could go a level lower and implement something like this:

HttpWebRequest webRequest = (HttpWebRequest)WebRequest.Create("http://www.yoursite.com/resource/file.htm");

using (StreamWriter streamWriter = new StreamWriter(webRequest.GetRequestStream(), Encoding.UTF8))
{
    streamWriter.Write(requestData);
}

string responseData = string.Empty;
HttpWebResponse httpResponse = (HttpWebResponse)webRequest.GetResponse();
using (StreamReader responseReader = new StreamReader(httpResponse.GetResponseStream()))
{
    responseData = responseReader.ReadToEnd();
}

However, at the end of the day the WebClient class wraps up this functionality for you. So I would suggest that you use WebClient and investigate the causes of the 30 second delay.

Remove spacing between table cells and rows

Add border-collapse: collapse into the style attribute value of the inner table element. You could alternatively add the attribute cellspacing=0 there, but then you would have a double border between the cells.

I.e.:

<table class="main-story-image" style="float: left; width: 180px; margin: 0 25px 25px 25px; border-collapse: collapse">

LF will be replaced by CRLF in git - What is that and is it important?

If you want, you can deactivate this feature in your git core config using

git config core.autocrlf false

But it would be better to just get rid of the warnings using

git config core.autocrlf true

vertical-align: middle doesn't work

You must wrap your element in a table-cell, within a table using display.

Like this:

<div>
  <span class='twoline'>Two line text</span>
  <span class='float'>Float right</span>
</div>

and

.float {
    display: table-cell;
    vertical-align: middle;
    text-align: right;
}
.twoline {
    width: 50px;
    display: table-cell;
}
div {
    display: table;
    border: solid 1px blue;
    width: 500px;
    height: 100px;
}

Shown here: http://jsfiddle.net/e8ESb/7/

Check if a class `active` exist on element with jquery

i wrote a helper method to help me go through all my selected elements and remove the active class.

    function removeClassFromElem(classSelect, classToRemove){
      $(classSelect).each(function(){
        var currElem=$(this);
        if(currElem.hasClass(classToRemove)){
          currElem.removeClass(classToRemove);
        }
      });
    }

    //usage
    removeClassFromElem('.someclass', 'active');

How do I solve this error, "error while trying to deserialize parameter"

In our case the problem was that we change the default root namespace name.

Project Configuration screen

This is the Project Configuration screen

We finally decided to back to the original name and the problem was solved.

The problem actually was the dots in the Root namespace. With two dots (Name.Child.Child) it doesnt work. But with one (Name.ChidChild) works.

How do you set the document title in React?

As others have mentioned, you can use document.title = 'My new title' and React Helmet to update the page title. Both of these solutions will still render the initial 'React App' title before scripts are loaded.

If you are using create-react-app the initial document title is set in the <title> tag /public/index.html file.

You can edit this directly or use a placeholder which will be filled from environmental variables:

/.env:

REACT_APP_SITE_TITLE='My Title!'
SOME_OTHER_VARS=...

If for some reason I wanted a different title in my development environment -

/.env.development:

REACT_APP_SITE_TITLE='**DEVELOPMENT** My TITLE! **DEVELOPMENT**'
SOME_OTHER_VARS=...

/public/index.html:

<!DOCTYPE html>
<html lang="en">
    <head>
         ...
         <title>%REACT_APP_SITE_TITLE%</title>
         ...
     </head>
     <body>
         ...
     </body>
</html>

This approach also means that I can read the site title environmental variable from my application using the global process.env object, which is nice:

console.log(process.env.REACT_APP_SITE_TITLE_URL);
// My Title!

See: Adding Custom Environment Variables

How to compare oldValues and newValues on React Hooks useEffect?

I just published react-delta which solves this exact sort of scenario. In my opinion, useEffect has too many responsibilities.

Responsibilities

  1. It compares all values in its dependency array using Object.is
  2. It runs effect/cleanup callbacks based on the result of #1

Breaking Up Responsibilities

react-delta breaks useEffect's responsibilities into several smaller hooks.

Responsibility #1

Responsibility #2

In my experience, this approach is more flexible, clean, and concise than useEffect/useRef solutions.

How can I permanently enable line numbers in IntelliJ?

In Intellij 13 the layout has changed, the Settings button can only be found in File -> Settings and not in the toolbars, and from there you follow the same steps: Editor -> Appearance -> Show line numbers, or search for Line numbers in the Settings search input.Intellij Settings search for line numbers

Angular @ViewChild() error: Expected 2 arguments, but got 1

That also resolved my issue.

@ViewChild('map', {static: false}) googleMap;

Beautiful way to remove GET-variables with PHP?

Ok, to remove all variables, maybe the prettiest is

$url = strtok($url, '?');

See about strtok here.

Its the fastest (see below), and handles urls without a '?' properly.

To take a url+querystring and remove just one variable (without using a regex replace, which may be faster in some cases), you might do something like:

function removeqsvar($url, $varname) {
    list($urlpart, $qspart) = array_pad(explode('?', $url), 2, '');
    parse_str($qspart, $qsvars);
    unset($qsvars[$varname]);
    $newqs = http_build_query($qsvars);
    return $urlpart . '?' . $newqs;
}

A regex replace to remove a single var might look like:

function removeqsvar($url, $varname) {
    return preg_replace('/([?&])'.$varname.'=[^&]+(&|$)/','$1',$url);
}

Heres the timings of a few different methods, ensuring timing is reset inbetween runs.

<?php

$number_of_tests = 40000;

$mtime = microtime();
$mtime = explode(" ",$mtime);
$mtime = $mtime[1] + $mtime[0];
$starttime = $mtime;

for($i = 0; $i < $number_of_tests; $i++){
    $str = "http://www.example.com?test=test";
    preg_replace('/\\?.*/', '', $str);
}
$mtime = microtime();
$mtime = explode(" ",$mtime);
$mtime = $mtime[1] + $mtime[0];
$endtime = $mtime;
$totaltime = ($endtime - $starttime);
echo "regexp execution time: ".$totaltime." seconds; ";

$mtime = microtime();
$mtime = explode(" ",$mtime);
$mtime = $mtime[1] + $mtime[0];
$starttime = $mtime;
for($i = 0; $i < $number_of_tests; $i++){
    $str = "http://www.example.com?test=test";
    $str = explode('?', $str);
}
$mtime = microtime();
$mtime = explode(" ",$mtime);
$mtime = $mtime[1] + $mtime[0];
$endtime = $mtime;
$totaltime = ($endtime - $starttime);
echo "explode execution time: ".$totaltime." seconds; ";

$mtime = microtime();
$mtime = explode(" ",$mtime);
$mtime = $mtime[1] + $mtime[0];
$starttime = $mtime;
for($i = 0; $i < $number_of_tests; $i++){
    $str = "http://www.example.com?test=test";
    $qPos = strpos($str, "?");
    $url_without_query_string = substr($str, 0, $qPos);
}
$mtime = microtime();
$mtime = explode(" ",$mtime);
$mtime = $mtime[1] + $mtime[0];
$endtime = $mtime;
$totaltime = ($endtime - $starttime);
echo "strpos execution time: ".$totaltime." seconds; ";

$mtime = microtime();
$mtime = explode(" ",$mtime);
$mtime = $mtime[1] + $mtime[0];
$starttime = $mtime;
for($i = 0; $i < $number_of_tests; $i++){
    $str = "http://www.example.com?test=test";
    $url_without_query_string = strtok($str, '?');
}
$mtime = microtime();
$mtime = explode(" ",$mtime);
$mtime = $mtime[1] + $mtime[0];
$endtime = $mtime;
$totaltime = ($endtime - $starttime);
echo "tok execution time: ".$totaltime." seconds; ";

shows

regexp execution time: 0.14604902267456 seconds; explode execution time: 0.068033933639526 seconds; strpos execution time: 0.064775943756104 seconds; tok execution time: 0.045819044113159 seconds; 
regexp execution time: 0.1408839225769 seconds; explode execution time: 0.06751012802124 seconds; strpos execution time: 0.064877986907959 seconds; tok execution time: 0.047760963439941 seconds; 
regexp execution time: 0.14162802696228 seconds; explode execution time: 0.065848112106323 seconds; strpos execution time: 0.064821004867554 seconds; tok execution time: 0.041788101196289 seconds; 
regexp execution time: 0.14043688774109 seconds; explode execution time: 0.066350221633911 seconds; strpos execution time: 0.066242933273315 seconds; tok execution time: 0.041517972946167 seconds; 
regexp execution time: 0.14228296279907 seconds; explode execution time: 0.06665301322937 seconds; strpos execution time: 0.063700199127197 seconds; tok execution time: 0.041836977005005 seconds; 

strtok wins, and is by far the smallest code.

How do I add multiple "NOT LIKE '%?%' in the WHERE clause of sqlite3?

If you have any problems with the "not like" query, Consider that you may have a null in the database. In this case, Use:

IFNULL(word, '') NOT LIKE '%something%'

Nested Git repositories?

Summary.

Can I nest git repositories?

Yes. However, by default git does not track the .git folder of the nested repository. Git has features designed to manage nested repositories (read on).

Does it make sense to git init/add the /project_root to ease management of everything locally or do I have to manage my_project and the 3rd party one separately?

It probably doesn't make sense as git has features to manage nested repositories. Git's built in features to manage nested repositories are submodule and subtree.

Here is a blog on the topic and here is a SO question that covers the pros and cons of using each.

Limit results in jQuery UI Autocomplete

I did it in following way :

success: function (result) {
response($.map(result.d.slice(0,10), function (item) {
return {
// Mapping to Required columns (Employee Name and Employee No)
label: item.EmployeeName,
value: item.EmployeeNo
}
}
));

How to build a 2 Column (Fixed - Fluid) Layout with Twitter Bootstrap?

Update 2018

Bootstrap 4

Now that BS4 is flexbox, the fixed-fluid is simple. Just set the width of the fixed column, and use the .col class on the fluid column.

.sidebar {
    width: 180px;
    min-height: 100vh;
}

<div class="row">
    <div class="sidebar p-2">Fixed width</div>
    <div class="col bg-dark text-white pt-2">
        Content
    </div>
</div>

http://www.codeply.com/go/7LzXiPxo6a

Bootstrap 3..

One approach to a fixed-fluid layout is using media queries that align with Bootstrap's breakpoints so that you only use the fixed width columns are larger screens and then let the layout stack responsively on smaller screens...

@media (min-width:768px) {
  #sidebar {
      min-width: 300px;
      max-width: 300px;
  }
  #main {
      width:calc(100% - 300px);
  }
}

Working Bootstrap 3 Fixed-Fluid Demo

Related Q&A:
Fixed width column with a container-fluid in bootstrap
How to left column fixed and right scrollable in Bootstrap 4, responsive?

Comparison of full text search engine - Lucene, Sphinx, Postgresql, MySQL?

I don't know Sphinx, but as for Lucene vs a database full-text search, I think that Lucene performance is unmatched. You should be able to do almost any search in less than 10 ms, no matter how many records you have to search, provided that you have set up your Lucene index correctly.

Here comes the biggest hurdle though: personally, I think integrating Lucene in your project is not easy. Sure, it is not too hard to set it up so you can do some basic search, but if you want to get the most out of it, with optimal performance, then you definitely need a good book about Lucene.

As for CPU & RAM requirements, performing a search in Lucene doesn't task your CPU too much, though indexing your data is, although you don't do that too often (maybe once or twice a day), so that isn't much of a hurdle.

It doesn't answer all of your questions but in short, if you have a lot of data to search, and you want great performance, then I think Lucene is definitely the way to go. If you're not going to have that much data to search, then you might as well go for a database full-text search. Setting up a MySQL full-text search is definitely easier in my book.

Loop through properties in JavaScript object with Lodash

You can definitely do this with vanilla JS like stecb has shown, but I think each is the best answer to the core question concerning how to do it with lodash.

_.each( myObject.options, ( val, key ) => { 
    console.log( key, val ); 
} );

Like JohnnyHK mentioned, there is also the has method which would be helpful for the use case, but from what is originally stated set may be more useful. Let's say you wanted to add something to this object dynamically as you've mentioned:

let dynamicKey = 'someCrazyProperty';
let dynamicValue = 'someCrazyValue';

_.set( myObject.options, dynamicKey, dynamicValue );

That's how I'd do it, based on the original description.

How to configure static content cache per folder and extension in IIS7?

I had the same issue.For me the problem was how to configure a cache limit to images.And i came across this site which gave some insights to the procedure on how the issue can be handled.Hope it will be helpful for you too Link:[https://varvy.com/pagespeed/cache-control.html]

Java and unlimited decimal places?

I believe that you are looking for the java.lang.BigDecimal class.

<div> cannot appear as a descendant of <p>

Based on the warning message, the component ReactTooltip renders an HTML that might look like this:

<p>
   <div>...</div>
</p>

According to this document, a <p></p> tag can only contain inline elements. That means putting a <div></div> tag inside it should be improper, since the div tag is a block element. Improper nesting might cause glitches like rendering extra tags, which can affect your javascript and css.

If you want to get rid of this warning, you might want to customize the ReactTooltip component, or wait for the creator to fix this warning.

data.frame rows to a list

A couple of more options :

With asplit

asplit(xy.df, 1)
#[[1]]
#     x      y 
#0.1137 0.6936 

#[[2]]
#     x      y 
#0.6223 0.5450 

#[[3]]
#     x      y 
#0.6093 0.2827 
#....

With split and row

split(xy.df, row(xy.df)[, 1])

#$`1`
#       x      y
#1 0.1137 0.6936

#$`2`
#       x     y
#2 0.6223 0.545

#$`3`
#       x      y
#3 0.6093 0.2827
#....

data

set.seed(1234)
xy.df <- data.frame(x = runif(10),  y = runif(10))

jQuery checkbox change and click event

// this works on all browsers.

$(document).ready(function() {
    //set initial state.
    $('#textbox1').val($(this).is(':checked'));

    $('#checkbox1').change(function(e) {
        this.checked =  $(this).is(":checked") && !!confirm("Are you sure?");
        $('#textbox1').val(this.checked);
        return true;
    });
});

Fit image into ImageView, keep aspect ratio and then resize ImageView to image dimensions?

Edited Jarno Argillanders answer:

How to fit Image with your Width and Height:

1) Initialize ImageView and set Image:

iv = (ImageView) findViewById(R.id.iv_image);
iv.setImageBitmap(image);

2) Now resize:

scaleImage(iv);

Edited scaleImage method: (you can replace EXPECTED bounding values)

private void scaleImage(ImageView view) {
    Drawable drawing = view.getDrawable();
    if (drawing == null) {
        return;
    }
    Bitmap bitmap = ((BitmapDrawable) drawing).getBitmap();

    int width = bitmap.getWidth();
    int height = bitmap.getHeight();
    int xBounding = ((View) view.getParent()).getWidth();//EXPECTED WIDTH
    int yBounding = ((View) view.getParent()).getHeight();//EXPECTED HEIGHT

    float xScale = ((float) xBounding) / width;
    float yScale = ((float) yBounding) / height;

    Matrix matrix = new Matrix();
    matrix.postScale(xScale, yScale);

    Bitmap scaledBitmap = Bitmap.createBitmap(bitmap, 0, 0, width, height, matrix, true);
    width = scaledBitmap.getWidth();
    height = scaledBitmap.getHeight();
    BitmapDrawable result = new BitmapDrawable(context.getResources(), scaledBitmap);

    view.setImageDrawable(result);

    LinearLayout.LayoutParams params = (LinearLayout.LayoutParams) view.getLayoutParams(); 
    params.width = width;
    params.height = height;
    view.setLayoutParams(params);
}

And .xml:

<ImageView
    android:id="@+id/iv_image"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_gravity="center_horizontal" />

Return HTML from ASP.NET Web API

ASP.NET Core. Approach 1

If your Controller extends ControllerBase or Controller you can use Content(...) method:

[HttpGet]
public ContentResult Index() 
{
    return base.Content("<div>Hello</div>", "text/html");
}

ASP.NET Core. Approach 2

If you choose not to extend from Controller classes, you can create new ContentResult:

[HttpGet]
public ContentResult Index() 
{
    return new ContentResult 
    {
        ContentType = "text/html",
        Content = "<div>Hello World</div>"
    };
}

Legacy ASP.NET MVC Web API

Return string content with media type text/html:

public HttpResponseMessage Get()
{
    var response = new HttpResponseMessage();
    response.Content = new StringContent("<div>Hello World</div>");
    response.Content.Headers.ContentType = new MediaTypeHeaderValue("text/html");
    return response;
}

Hyper-V: Create shared folder between host and guest with internal network

  • Open Hyper-V Manager
  • Create a new internal virtual switch (e.g. "Internal Network Connection")
  • Go to your Virtual Machine and create a new Network Adapter -> choose "Internal Network Connection" as virtual switch
  • Start the VM
  • Assign both your host as well as guest an IP address as well as a Subnet mask (IP4, e.g. 192.168.1.1 (host) / 192.168.1.2 (guest) and 255.255.255.0)
  • Open cmd both on host and guest and check via "ping" if host and guest can reach each other (if this does not work disable/enable the network adapter via the network settings in the control panel, restart...)
  • If successfull create a folder in the VM (e.g. "VMShare"), right-click on it -> Properties -> Sharing -> Advanced Sharing -> checkmark "Share this folder" -> Permissions -> Allow "Full Control" -> Apply
  • Now you should be able to reach the folder via the host -> to do so: open Windows Explorer -> enter the path to the guest (\192.168.1.xx...) in the address line -> enter the credentials of the guest (Choose "Other User" - it can be necessary to change the domain therefore enter ".\"[username] and [password])

There is also an easy way for copying via the clipboard:

  • If you start your VM and go to "View" you can enable "Enhanced Session". If you do it is not possible to drag and drop but to copy and paste.

Enhanced Session

How to check if an object is a certain type

In VB.NET, you need to use the GetType method to retrieve the type of an instance of an object, and the GetType() operator to retrieve the type of another known type.

Once you have the two types, you can simply compare them using the Is operator.

So your code should actually be written like this:

Sub FillCategories(ByVal Obj As Object)
    Dim cmd As New SqlCommand("sp_Resources_Categories", Conn)
    cmd.CommandType = CommandType.StoredProcedure
    Obj.DataSource = cmd.ExecuteReader
    If Obj.GetType() Is GetType(System.Web.UI.WebControls.DropDownList) Then

    End If
    Obj.DataBind()
End Sub

You can also use the TypeOf operator instead of the GetType method. Note that this tests if your object is compatible with the given type, not that it is the same type. That would look like this:

If TypeOf Obj Is System.Web.UI.WebControls.DropDownList Then

End If

Totally trivial, irrelevant nitpick: Traditionally, the names of parameters are camelCased (which means they always start with a lower-case letter) when writing .NET code (either VB.NET or C#). This makes them easy to distinguish at a glance from classes, types, methods, etc.

Reading InputStream as UTF-8

String file = "";

try {

    InputStream is = new FileInputStream(filename);
    String UTF8 = "utf8";
    int BUFFER_SIZE = 8192;

    BufferedReader br = new BufferedReader(new InputStreamReader(is,
            UTF8), BUFFER_SIZE);
    String str;
    while ((str = br.readLine()) != null) {
        file += str;
    }
} catch (Exception e) {

}

Try this,.. :-)

Alternate table row color using CSS?

You have the :nth-child() pseudo-class:

table tr:nth-child(odd) td{
    ...
}
table tr:nth-child(even) td{
    ...
}

In the early days of :nth-child() its browser support was kind of poor. That's why setting class="odd" became such a common technique. In late 2013 I'm glad to say that IE6 and IE7 are finally dead (or sick enough to stop caring) but IE8 is still around — thankfully, it's the only exception.

Add leading zeroes/0's to existing Excel values to certain length

I hit this page trying to pad hexadecimal values when I realized that DEC2HEX() provides that very feature for free.

You just need to add a second parameter. For example, tying to turn 12 into 0C
DEC2HEX(12,2) => 0C
DEC2HEX(12,4) => 000C
... and so on

Get absolute path to workspace directory in Jenkins Pipeline plugin

"WORKSPACE" environment variable works for the latest version of Jenkins Pipeline. You can use this in your Jenkins file: "${env.WORKSPACE}"

Sample use below:

def files = findFiles glob: '**/reports/*.json'
for (def i=0; i<files.length; i++) {
jsonFilePath = "${files[i].path}"       
jsonPath = "${env.WORKSPACE}" + "/" + jsonFilePath
echo jsonPath

hope that helps!!

Batch file to run a command in cmd within a directory

Mine DID execute commands in order. Here's my version of what I was using it for:

START cmd.exe /k "U: & cd U:\Design_stuff\new_lcso_website_2017 & python -m http.server"

I needed to

  1. Change to my U drive
  2. CD to a specific folder containing a website I'm redesigning
  3. Execute python with the http server module (to display the contents in my browser).

If those commands are out of order, it would not display the correct files. I initially forgot to change to U: and, running the batch file on my Desktop, it created a web page in my browser at http://localhost:8000 showing me the contents of my Desktop instead of the folder I wanted.

Append data to a POST NSURLRequest

All the changes to the NSMutableURLRequest must be made before calling NSURLConnection.

I see this problem as I copy and paste the code above and run TCPMon and see the request is GET instead of the expected POST.

NSURL *aUrl = [NSURL URLWithString:@"http://www.apple.com/"];
NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:aUrl
                                     cachePolicy:NSURLRequestUseProtocolCachePolicy
                                 timeoutInterval:60.0];


[request setHTTPMethod:@"POST"];
NSString *postString = @"company=Locassa&quality=AWESOME!";
[request setHTTPBody:[postString dataUsingEncoding:NSUTF8StringEncoding]];

NSURLConnection *connection= [[NSURLConnection alloc] initWithRequest:request 
                                                         delegate:self];

`require': no such file to load -- mkmf (LoadError)

You can use RVM(Ruby version manager) which helps in managing all versions of ruby on your machine , which is very helpful for you development (when migrating to unstable release to stable release )

or for Linux (ubuntu) go for sudo apt-get install ruby1.8-dev

then sudo gem install rails to verify it do rails -v it will show version on rails

after that you can install bundles (required gems for development)

Parse JSON String into a Particular Object Prototype in JavaScript

Do you want to add JSON serialization/deserialization functionality, right? Then look at this:

You want to achieve this:

UML

toJson() is a normal method.
fromJson() is a static method.

Implementation:

var Book = function (title, author, isbn, price, stock){
    this.title = title;
    this.author = author;
    this.isbn = isbn;
    this.price = price;
    this.stock = stock;

    this.toJson = function (){
        return ("{" +
            "\"title\":\"" + this.title + "\"," +
            "\"author\":\"" + this.author + "\"," +
            "\"isbn\":\"" + this.isbn + "\"," +
            "\"price\":" + this.price + "," +
            "\"stock\":" + this.stock +
        "}");
    };
};

Book.fromJson = function (json){
    var obj = JSON.parse (json);
    return new Book (obj.title, obj.author, obj.isbn, obj.price, obj.stock);
};

Usage:

var book = new Book ("t", "a", "i", 10, 10);
var json = book.toJson ();
alert (json); //prints: {"title":"t","author":"a","isbn":"i","price":10,"stock":10}

var book = Book.fromJson (json);
alert (book.title); //prints: t

Note: If you want you can change all property definitions like this.title, this.author, etc by var title, var author, etc. and add getters to them to accomplish the UML definition.

JPA Query.getResultList() - use in a generic way

If you need a more convenient way to access the results, it's possible to transform the result of an arbitrarily complex SQL query to a Java class with minimal hassle:

Query query = em.createNativeQuery("select 42 as age, 'Bob' as name from dual", 
        MyTest.class);
MyTest myTest = (MyTest) query.getResultList().get(0);
assertEquals("Bob", myTest.name);

The class needs to be declared an @Entity, which means you must ensure it has an unique @Id.

@Entity
class MyTest {
    @Id String name;
    int age;
}

How can I select all rows with sqlalchemy?

I use the following snippet to view all the rows in a table. Use a query to find all the rows. The returned objects are the class instances. They can be used to view/edit the values as required:

from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy import create_engine, Sequence
from sqlalchemy import String, Integer, Float, Boolean, Column
from sqlalchemy.orm import sessionmaker

Base = declarative_base()

class MyTable(Base):
    __tablename__ = 'MyTable'
    id = Column(Integer, Sequence('user_id_seq'), primary_key=True)
    some_col = Column(String(500))

    def __init__(self, some_col):
        self.some_col = some_col

engine = create_engine('sqlite:///sqllight.db', echo=True)
Session = sessionmaker(bind=engine)
session = Session()

for class_instance in session.query(MyTable).all():
    print(vars(class_instance))

session.close()

Java error: Implicit super constructor is undefined for default constructor

You could also get this error when JRE is not set. If so, try adding JRE System Library to your project.

Under Eclipse IDE:

  1. open menu Project --> Properties, or right-click on your project in Package Explorer and choose Properties (Alt+Enter on Windows, Command+I on Mac)
  2. click on Java Build Path then Libraries tab
  3. choose Modulepath or Classpath and press Add Library... button
  4. select JRE System Library then click Next
  5. keep Workspace default JRE selected (you can also take another option) and click Finish
  6. finally press Apply and Close.

Exception: Can't bind to 'ngFor' since it isn't a known native property

Just to cover one more case when I was getting the same error and the reason was using in instead of of in iterator

Wrong way let file in files

Correct way let file of files

How to remove all ListBox items?

  • VB ListBox2.DataSource = Nothing
  • C# ListBox2.DataSource = null;

Nth word in a string variable

echo $STRING | cut -d " " -f $N

Importing csv file into R - numeric values read as characters

version for data.table based on code from dmanuge :

convNumValues<-function(ds){
  ds<-data.table(ds)
  dsnum<-data.table(data.matrix(ds))
  num_cols <- sapply(dsnum,function(x){mean(as.numeric(is.na(x)))<0.5})
  nds <- data.table(  dsnum[, .SD, .SDcols=attributes(num_cols)$names[which(num_cols)]]
                        ,ds[, .SD, .SDcols=attributes(num_cols)$names[which(!num_cols)]] )
return(nds)
}

top nav bar blocking top content of the page

you can set margin based on screen resolution

@media screen and (min-width:768px) and (max-width:991px) {
body {
    margin-top:100px;
}

@media screen and (min-width:992px) and (max-width:1199px) {
  body {
    margin-top:50px;
  }
}

body{
  padding-top: 10%;
}

#nav{
   position: fixed;
   background-color: #8b0000;
   width: 100%;
   top:0;
}

estimating of testing effort as a percentage of development time

Gartner in Oct 2006 states that testing typically consumes between 10% and 35% of work on a system integration project. I assume that it applies to the waterfall method. This is quite a wide range - but there are many dependencies on the amount of customisations to a standard product and the number of systems to be integrated.

How do I iterate over a range of numbers defined by variables in Bash?

If you need it prefix than you might like this

 for ((i=7;i<=12;i++)); do echo `printf "%2.0d\n" $i |sed "s/ /0/"`;done

that will yield

07
08
09
10
11
12

Postgresql, update if row with some unique value exists, else insert

Firstly It tries insert. If there is a conflict on url column then it updates content and last_analyzed fields. If updates are rare this might be better option.

INSERT INTO URLs (url, content, last_analyzed)
VALUES
    (
        %(url)s,
        %(content)s,
        NOW()
    ) 
ON CONFLICT (url) 
DO
UPDATE
SET content=%(content)s, last_analyzed = NOW();

Passing arrays as url parameter

There is a very simple solution: http_build_query(). It takes your query parameters as an associative array:

$data = array(
    1,
    4,
    'a' => 'b',
    'c' => 'd'
);
$query = http_build_query(array('aParam' => $data));

will return

string(63) "aParam%5B0%5D=1&aParam%5B1%5D=4&aParam%5Ba%5D=b&aParam%5Bc%5D=d"

http_build_query() handles all the necessary escaping for you (%5B => [ and %5D => ]), so this string is equal to aParam[0]=1&aParam[1]=4&aParam[a]=b&aParam[c]=d.

Google Maps V3 - How to calculate the zoom level for a given bounds

None of the highly upvoted answers worked for me. They threw various undefined errors and ended up calculating inf/nan for angles. I suspect perhaps the behavior of LatLngBounds has changed over time. In any case, I found this code to work for my needs, perhaps it can help someone:

function latRad(lat) {
  var sin = Math.sin(lat * Math.PI / 180);
  var radX2 = Math.log((1 + sin) / (1 - sin)) / 2;
  return Math.max(Math.min(radX2, Math.PI), -Math.PI) / 2;
}

function getZoom(lat_a, lng_a, lat_b, lng_b) {

      let latDif = Math.abs(latRad(lat_a) - latRad(lat_b))
      let lngDif = Math.abs(lng_a - lng_b)

      let latFrac = latDif / Math.PI 
      let lngFrac = lngDif / 360 

      let lngZoom = Math.log(1/latFrac) / Math.log(2)
      let latZoom = Math.log(1/lngFrac) / Math.log(2)

      return Math.min(lngZoom, latZoom)

}

html "data-" attribute as javascript parameter

The short answer is that the syntax is this.dataset.whatever.

Your code should look like this:

<div data-uid="aaa" data-name="bbb" data-value="ccc"
    onclick="fun(this.dataset.uid, this.dataset.name, this.dataset.value)">

Another important note: Javascript will always strip out hyphens and make the data attributes camelCase, regardless of whatever capitalization you use. data-camelCase will become this.dataset.camelcase and data-Camel-case will become this.dataset.camelCase.

jQuery (after v1.5 and later) always uses lowercase, regardless of your capitalization.

So when referencing your data attributes using this method, remember the camelCase:

<div data-this-is-wild="yes, it's true"
    onclick="fun(this.dataset.thisIsWild)">

Also, you don't need to use commas to separate attributes.

Test for multiple cases in a switch, like an OR (||)

You need to make two case labels.

Control will fall through from the first label to the second, so they'll both execute the same code.

How to parseInt in Angular.js

Inside template this working finely.

<!DOCTYPE html>
<html>
<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.6.9/angular.min.js"></script>
<body>

<div ng-app="">
<input ng-model="name" value="0">
<p>My first expression: {{ (name-0) + 5 }}</p>
</div>

</body>
</html>

How should I store GUID in MySQL tables?

Binary(16) would be fine, better than use of varchar(32).

Why is my power operator (^) not working?

There is no way to use the ^ (Bitwise XOR) operator to calculate the power of a number. Therefore, in order to calculate the power of a number we have two options, either we use a while loop or the pow() function.

1. Using a while loop.

#include <stdio.h>

int main() {

    int base, expo;
    long long result = 1;

    printf("Enter a base no.: ");
    scanf("%d", &base);

    printf("Enter an exponent: ");
    scanf("%d", &expo);

    while (expo != 0) {
        result *= base;
        --expo;
    }

    printf("Answer = %lld", result);
    return 0;
}    
             

2. Using the pow() function

#include <math.h>
#include <stdio.h>

int main() {

    double base, exp, result;

    printf("Enter a base number: ");
    scanf("%lf", &base);

    printf("Enter an exponent: ");
    scanf("%lf", &exp);

    // calculate the power of our input numbers
    result = pow(base, exp);

    printf("%.1lf^%.1lf = %.2lf", base, exp, result);

    return 0;
}
     

Disable button in jQuery

Simply it's work fine, in HTML:

<button type="button" id="btn_CommitAll"class="btn_CommitAll">save</button>

In JQuery side put this function for disable button:

function disableButton() {
    $('.btn_CommitAll').prop("disabled", true);
}

For enable button:

function enableButton() {
    $('.btn_CommitAll').prop("disabled", false);
}

That's all.

How to make a pure css based dropdown menu?

There is different ways to make dropdown menu using css. Here is simple code.

HTML Code

    <label class="dropdown">

  <div class="dd-button">
    Dropdown
  </div>

  <input type="checkbox" class="dd-input" id="test">

  <ul class="dd-menu">
    <li>Dropdown 1</li>
    <li>Dropdown 2</li>
  </ul>

</label>

CSS Code

body {
  color: #000000;
  font-family: Sans-Serif;
  padding: 30px;
  background-color: #f6f6f6;
}

a {
  text-decoration: none;
  color: #000000;
}

a:hover {
  color: #222222
}

/* Dropdown */

.dropdown {
  display: inline-block;
  position: relative;
}

.dd-button {
  display: inline-block;
  border: 1px solid gray;
  border-radius: 4px;
  padding: 10px 30px 10px 20px;
  background-color: #ffffff;
  cursor: pointer;
  white-space: nowrap;
}

.dd-button:after {
  content: '';
  position: absolute;
  top: 50%;
  right: 15px;
  transform: translateY(-50%);
  width: 0; 
  height: 0; 
  border-left: 5px solid transparent;
  border-right: 5px solid transparent;
  border-top: 5px solid black;
}

.dd-button:hover {
  background-color: #eeeeee;
}


.dd-input {
  display: none;
}

.dd-menu {
  position: absolute;
  top: 100%;
  border: 1px solid #ccc;
  border-radius: 4px;
  padding: 0;
  margin: 2px 0 0 0;
  box-shadow: 0 0 6px 0 rgba(0,0,0,0.1);
  background-color: #ffffff;
  list-style-type: none;
}

.dd-input + .dd-menu {
  display: none;
} 

.dd-input:checked + .dd-menu {
  display: block;
} 

.dd-menu li {
  padding: 10px 20px;
  cursor: pointer;
  white-space: nowrap;
}

.dd-menu li:hover {
  background-color: #f6f6f6;
}

.dd-menu li a {
  display: block;
  margin: -10px -20px;
  padding: 10px 20px;
}

.dd-menu li.divider{
  padding: 0;
  border-bottom: 1px solid #cccccc;
}

More css code example