Programs & Examples On #Generic.xaml

For issues relating to the generic.xaml file which is used to define default styles of custom WPF controls.

How to get ID of the last updated row in MySQL?

If you are only doing insertions, and want one from the same session, do as per peirix's answer. If you are doing modifications, you will need to modify your database schema to store which entry was most recently updated.

If you want the id from the last modification, which may have been from a different session (i.e. not the one that was just done by the PHP code running at present, but one done in response to a different request), you can add a TIMESTAMP column to your table called last_modified (see http://dev.mysql.com/doc/refman/5.1/en/datetime.html for information), and then when you update, set last_modified=CURRENT_TIME.

Having set this, you can then use a query like: SELECT id FROM table ORDER BY last_modified DESC LIMIT 1; to get the most recently modified row.

master branch and 'origin/master' have diverged, how to 'undiverge' branches'?

To view the differences:

git difftool --dir-diff master origin/master

This will display the changes or differences between the two branches. In araxis (My favorite) it displays it in a folder diff style. Showing each of the changed files. I can then click on a file to see the details of the changes in the file.

Drop rows containing empty cells from a pandas DataFrame

Pythonic + Pandorable: df[df['col'].astype(bool)]

Empty strings are falsy, which means you can filter on bool values like this:

df = pd.DataFrame({
    'A': range(5),
    'B': ['foo', '', 'bar', '', 'xyz']
})
df
   A    B
0  0  foo
1  1     
2  2  bar
3  3     
4  4  xyz
df['B'].astype(bool)                                                                                                                      
0     True
1    False
2     True
3    False
4     True
Name: B, dtype: bool

df[df['B'].astype(bool)]                                                                                                                  
   A    B
0  0  foo
2  2  bar
4  4  xyz

If your goal is to remove not only empty strings, but also strings only containing whitespace, use str.strip beforehand:

df[df['B'].str.strip().astype(bool)]
   A    B
0  0  foo
2  2  bar
4  4  xyz

Faster than you Think

.astype is a vectorised operation, this is faster than every option presented thus far. At least, from my tests. YMMV.

Here is a timing comparison, I've thrown in some other methods I could think of.

enter image description here

Benchmarking code, for reference:

import pandas as pd
import perfplot

df1 = pd.DataFrame({
    'A': range(5),
    'B': ['foo', '', 'bar', '', 'xyz']
})

perfplot.show(
    setup=lambda n: pd.concat([df1] * n, ignore_index=True),
    kernels=[
        lambda df: df[df['B'].astype(bool)],
        lambda df: df[df['B'] != ''],
        lambda df: df[df['B'].replace('', np.nan).notna()],  # optimized 1-col
        lambda df: df.replace({'B': {'': np.nan}}).dropna(subset=['B']),  
    ],
    labels=['astype', "!= ''", "replace + notna", "replace + dropna", ],
    n_range=[2**k for k in range(1, 15)],
    xlabel='N',
    logx=True,
    logy=True,
    equality_check=pd.DataFrame.equals)

How to fix JSP compiler warning: one JAR was scanned for TLDs yet contained no TLDs?

The warning comes up because Tomcat scans all Jars for TLDs (Tagging Library Definitions).

Step1: To see which JARs are throwing up this warning, insert he following line to tomcat/conf/logging.properties

org.apache.jasper.servlet.TldScanner.level = FINE

Now you should be able to see warnings with a detail of which JARs are causing the intial warning

Step2 Since skipping unneeded JARs during scanning can improve startup time and JSP compilation time, we will skip un-needed JARS in the catalina.properties file. You have two options here -

  1. List all the JARs under the tomcat.util.scan.StandardJarScanFilter.jarsToSkip. But this can get cumbersome if you have a lot jars or if the jars keep changing.
  2. Alternatively, Insert tomcat.util.scan.StandardJarScanFilter.jarsToSkip=* to skip all the jars

You should now not see the above warnings and if you have a considerably large application, it should save you significant time in deploying an application.

Note: Tested in Tomcat8

How do I get the path of the current executed file in Python?

First, you need to import from inspect and os

from inspect import getsourcefile
from os.path import abspath

Next, wherever you want to find the source file from you just use

abspath(getsourcefile(lambda:0))

How do I rename a repository on GitHub?

I have tried to rename the repository on the web page:

  1. Click on the top of the right pages that it's your avatar.
  2. you can look at the icon of setting, click it and then you can find the Repositories under the Personal setting.
  3. click the Repositories and enter your directories of Repositories, choose the Repository that you want to rename.
  4. Then you will enter the chosen Repository and you will find the icon of setting is added to the top line, just click it and enter the new name then click Rename.

Done, so easy.

Laravel Eloquent - Get one Row

You can also use this

$user = User::whereEmail($email)->first();

How to add checkboxes to JTABLE swing

1) JTable knows JCheckbox with built-in Boolean TableCellRenderers and TableCellEditor by default, then there is contraproductive declare something about that,

2) AbstractTableModel should be useful, where is in the JTable required to reduce/restrict/change nested and inherits methods by default implemented in the DefaultTableModel,

3) consider using DefaultTableModel, (if you are not sure about how to works) instead of AbstractTableModel,

table_with_BooleanType_column

could be generated from simple code:

import javax.swing.*;
import javax.swing.table.*;

public class TableCheckBox extends JFrame {

    private static final long serialVersionUID = 1L;
    private JTable table;

    public TableCheckBox() {
        Object[] columnNames = {"Type", "Company", "Shares", "Price", "Boolean"};
        Object[][] data = {
            {"Buy", "IBM", new Integer(1000), new Double(80.50), false},
            {"Sell", "MicroSoft", new Integer(2000), new Double(6.25), true},
            {"Sell", "Apple", new Integer(3000), new Double(7.35), true},
            {"Buy", "Nortel", new Integer(4000), new Double(20.00), false}
        };
        DefaultTableModel model = new DefaultTableModel(data, columnNames);
        table = new JTable(model) {

            private static final long serialVersionUID = 1L;

            /*@Override
            public Class getColumnClass(int column) {
            return getValueAt(0, column).getClass();
            }*/
            @Override
            public Class getColumnClass(int column) {
                switch (column) {
                    case 0:
                        return String.class;
                    case 1:
                        return String.class;
                    case 2:
                        return Integer.class;
                    case 3:
                        return Double.class;
                    default:
                        return Boolean.class;
                }
            }
        };
        table.setPreferredScrollableViewportSize(table.getPreferredSize());
        JScrollPane scrollPane = new JScrollPane(table);
        getContentPane().add(scrollPane);
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {

            @Override
            public void run() {
                TableCheckBox frame = new TableCheckBox();
                frame.setDefaultCloseOperation(EXIT_ON_CLOSE);
                frame.pack();
                frame.setLocation(150, 150);
                frame.setVisible(true);
            }
        });
    }
}

What is the proper way to re-throw an exception in C#?

The first preserves the original stack trace of the exception, the second one replaces it with the current location.

Therefore the first is BY FAR the better.

Make DateTimePicker work as TimePicker only in WinForms

Add below event to DateTimePicker

Private Sub DateTimePicker1_KeyPress(sender As Object, e As KeyPressEventArgs) Handles DateTimePicker1.KeyPress
    e.Handled = True
End Sub

Checking if a textbox is empty in Javascript

function valid(id)
    {
        var textVal=document.getElementById(id).value;
        if (!textVal.match("Tryit") 
        {
            alert("Field says Tryit");
            return false;
        } 
        else 
        {
            return true;
        }
     }

Use this for expressing things

Speed tradeoff of Java's -Xms and -Xmx options

I have found that in some cases too much memory can slow the program down.

For example I had a hibernate based transform engine that started running slowly as the load increased. It turned out that each time we got an object from the db, hibernate was checking memory for objects that would never be used again.

The solution was to evict the old objects from the session.

Stuart

How can INSERT INTO a table 300 times within a loop in SQL?

DECLARE @first AS INT = 1
DECLARE @last AS INT = 300

WHILE(@first <= @last)
BEGIN
    INSERT INTO tblFoo VALUES(@first)
    SET @first += 1
END

Are there any SHA-256 javascript implementations that are generally considered trustworthy?

Besides the Stanford lib that tylerl mentioned. I found jsrsasign very useful (Github repo here:https://github.com/kjur/jsrsasign). I don't know how exactly trustworthy it is, but i've used its API of SHA256, Base64, RSA, x509 etc. and it works pretty well. In fact, it includes the Stanford lib as well.

If all you want to do is SHA256, jsrsasign might be a overkill. But if you have other needs in the related area, I feel it's a good fit.

Fatal error: Class 'PHPMailer' not found

PHPMailerAutoload needs to be in the same folder as class.phpmailer.php

This is the PHPMailerAutoload code that I assume this:

 $filename = dirname(__FILE__).DIRECTORY_SEPARATOR.'class.'.strtolower($classname).'.php';

How to list the files inside a JAR file?

A jar file is just a zip file with a structured manifest. You can open the jar file with the usual java zip tools and scan the file contents that way, inflate streams, etc. Then use that in a getResourceAsStream call, and it should be all hunky dory.

EDIT / after clarification

It took me a minute to remember all the bits and pieces and I'm sure there are cleaner ways to do it, but I wanted to see that I wasn't crazy. In my project image.jpg is a file in some part of the main jar file. I get the class loader of the main class (SomeClass is the entry point) and use it to discover the image.jpg resource. Then some stream magic to get it into this ImageInputStream thing and everything is fine.

InputStream inputStream = SomeClass.class.getClassLoader().getResourceAsStream("image.jpg");
JPEGImageReaderSpi imageReaderSpi = new JPEGImageReaderSpi();
ImageReader ir = imageReaderSpi.createReaderInstance();
ImageInputStream iis = new MemoryCacheImageInputStream(inputStream);
ir.setInput(iis);
....
ir.read(0); //will hand us a buffered image

How to export data as CSV format from SQL Server using sqlcmd?

You can do it in a hackish way. Careful using the sqlcmd hack. If the data has double quotes or commas you will run into trouble.

You can use a simple script to do it properly:

'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
' Data Exporter                                                 '
'                                                               '
' Description: Allows the output of data to CSV file from a SQL '
'       statement to either Oracle, SQL Server, or MySQL        '
' Author: C. Peter Chen, http://dev-notes.com                   '
' Version Tracker:                                              '
'       1.0   20080414 Original version                         '
'   1.1   20080807 Added email functionality                '
'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
option explicit
dim dbType, dbHost, dbName, dbUser, dbPass, outputFile, email, subj, body, smtp, smtpPort, sqlstr

'''''''''''''''''
' Configuration '
'''''''''''''''''
dbType = "oracle"                 ' Valid values: "oracle", "sqlserver", "mysql"
dbHost = "dbhost"                 ' Hostname of the database server
dbName = "dbname"                 ' Name of the database/SID
dbUser = "username"               ' Name of the user
dbPass = "password"               ' Password of the above-named user
outputFile = "c:\output.csv"      ' Path and file name of the output CSV file
email = "[email protected]"           ' Enter email here should you wish to email the CSV file (as attachment); if no email, leave it as empty string ""
  subj = "Email Subject"          ' The subject of your email; required only if you send the CSV over email
  body = "Put a message here!"    ' The body of your email; required only if you send the CSV over email
  smtp = "mail.server.com"        ' Name of your SMTP server; required only if you send the CSV over email
  smtpPort = 25                   ' SMTP port used by your server, usually 25; required only if you send the CSV over email
sqlStr = "select user from dual"  ' SQL statement you wish to execute
'''''''''''''''''''''
' End Configuration '
'''''''''''''''''''''



dim fso, conn

'Create filesystem object 
set fso = CreateObject("Scripting.FileSystemObject")

'Database connection info
set Conn = CreateObject("ADODB.connection")
Conn.ConnectionTimeout = 30
Conn.CommandTimeout = 30
if dbType = "oracle" then
    conn.open("Provider=MSDAORA.1;User ID=" & dbUser & ";Password=" & dbPass & ";Data Source=" & dbName & ";Persist Security Info=False")
elseif dbType = "sqlserver" then
    conn.open("Driver={SQL Server};Server=" & dbHost & ";Database=" & dbName & ";Uid=" & dbUser & ";Pwd=" & dbPass & ";")
elseif dbType = "mysql" then
    conn.open("DRIVER={MySQL ODBC 3.51 Driver}; SERVER=" & dbHost & ";PORT=3306;DATABASE=" & dbName & "; UID=" & dbUser & "; PASSWORD=" & dbPass & "; OPTION=3")
end if

' Subprocedure to generate data.  Two parameters:
'   1. fPath=where to create the file
'   2. sqlstr=the database query
sub MakeDataFile(fPath, sqlstr)
    dim a, showList, intcount
    set a = fso.createtextfile(fPath)

    set showList = conn.execute(sqlstr)
    for intcount = 0 to showList.fields.count -1
        if intcount <> showList.fields.count-1 then
            a.write """" & showList.fields(intcount).name & ""","
        else
            a.write """" & showList.fields(intcount).name & """"
        end if
    next
    a.writeline ""

    do while not showList.eof
        for intcount = 0 to showList.fields.count - 1
            if intcount <> showList.fields.count - 1 then
                a.write """" & showList.fields(intcount).value & ""","
            else
                a.write """" & showList.fields(intcount).value & """"
            end if
        next
        a.writeline ""
        showList.movenext
    loop
    showList.close
    set showList = nothing

    set a = nothing
end sub

' Call the subprocedure
call MakeDataFile(outputFile,sqlstr)

' Close
set fso = nothing
conn.close
set conn = nothing

if email <> "" then
    dim objMessage
    Set objMessage = CreateObject("CDO.Message")
    objMessage.Subject = "Test Email from vbs"
    objMessage.From = email
    objMessage.To = email
    objMessage.TextBody = "Please see attached file."
    objMessage.AddAttachment outputFile

    objMessage.Configuration.Fields.Item ("http://schemas.microsoft.com/cdo/configuration/sendusing") = 2
    objMessage.Configuration.Fields.Item ("http://schemas.microsoft.com/cdo/configuration/smtpserver") = smtp
    objMessage.Configuration.Fields.Item ("http://schemas.microsoft.com/cdo/configuration/smtpserverport") = smtpPort

objMessage.Configuration.Fields.Update

    objMessage.Send
end if

'You're all done!!  Enjoy the file created.
msgbox("Data Writer Done!")

Source: Writing SQL output to CSV with VBScript.

Changing column names of a data frame

If you need to rename not all but multiple column at once when you only know the old column names you can use colnames function and %in% operator. Example:

df = data.frame(bad=1:3, worse=rnorm(3), worst=LETTERS[1:3])

   bad      worse    worst
1   1 -0.77915455       A
2   2  0.06717385       B
3   3 -0.02827242       C

Now you want to change "bad" and "worst" to "good" and "best". You can use

colnames(df)[which(colnames(df) %in% c("bad","worst") )] <- c("good","best")

This results in

  good      worse  best
1    1 -0.6010363    A
2    2  0.7336155    B
3    3  0.9435469    C

Unix command to find lines common in two files

Maybe you mean comm ?

Compare sorted files FILE1 and FILE2 line by line.

With no options, produce three-column output. Column one contains lines unique to FILE1, column two contains lines unique to FILE2, and column three contains lines common to both files.

The secret in finding these information are the info pages. For GNU programs, they are much more detailed than their man-pages. Try info coreutils and it will list you all the small useful utils.

Returning http status code from Web Api controller

I don't like having to change my signature to use the HttpCreateResponse type, so I came up with a little bit of an extended solution to hide that.

public class HttpActionResult : IHttpActionResult
{
    public HttpActionResult(HttpRequestMessage request) : this(request, HttpStatusCode.OK)
    {
    }

    public HttpActionResult(HttpRequestMessage request, HttpStatusCode code) : this(request, code, null)
    {
    }

    public HttpActionResult(HttpRequestMessage request, HttpStatusCode code, object result)
    {
        Request = request;
        Code = code;
        Result = result;
    }

    public HttpRequestMessage Request { get; }
    public HttpStatusCode Code { get; }
    public object Result { get; }

    public Task<HttpResponseMessage> ExecuteAsync(CancellationToken cancellationToken)
    {
        return Task.FromResult(Request.CreateResponse(Code, Result));
    }
}

You can then add a method to your ApiController (or better your base controller) like this:

protected IHttpActionResult CustomResult(HttpStatusCode code, object data) 
{
    // Request here is the property on the controller.
    return new HttpActionResult(Request, code, data);
}

Then you can return it just like any of the built in methods:

[HttpPost]
public IHttpActionResult Post(Model model)
{
    return model.Id == 1 ?
                Ok() :
                CustomResult(HttpStatusCode.NotAcceptable, new { 
                    data = model, 
                    error = "The ID needs to be 1." 
                });
}

How to convert SQL Query result to PANDAS Data Structure?

If you are using SQLAlchemy's ORM rather than the expression language, you might find yourself wanting to convert an object of type sqlalchemy.orm.query.Query to a Pandas data frame.

The cleanest approach is to get the generated SQL from the query's statement attribute, and then execute it with pandas's read_sql() method. E.g., starting with a Query object called query:

df = pd.read_sql(query.statement, query.session.bind)

How to SHA1 hash a string in Android?

String.format("%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X", result[0], result[1], result[2], result[3], 
    result[4], result[5], result[6], result[7],
    result[8], result[9], result[10], result[11],
    result[12], result[13], result[14], result[15],
    result[16], result[17], result[18], result[19]);

compare differences between two tables in mysql

Problem below, is to compare table before and after i do big update!.

If you use Linux, you can use commands as follow:

In terminal,

mysqldump -hlocalhost -uroot -p schema_name_here table_name_here > /home/ubuntu/database_dumps/dump_table_before_running_update.sql

mysqldump -hlocalhost -uroot -p schema_name_here table_name_here > /home/ubuntu/database_dumps/dump_table_after_running_update.sql

diff -uP /home/ubuntu/database_dumps/dump_some_table_after_running_update.sql /home/ubuntu/database_dumps/dump_table_before_running_update.sql > /home/ubuntu/database_dumps/diff.txt

You will need online tools for

  • Formatting SQL exported from the dumps,

e.g http://www.dpriver.com/pp/sqlformat.htm [Not the best I've seen]

  • We have diff.txt, you have to take manually the + - showing inside, which is 1 line of insert statements, that has the values.

  • Do diff online for the 2 lines - & + in diff.txt, past them in online diff tool

e.g https://www.diffchecker.com [you can save and share it, and has no limit on file size!]

Note: be extra careful if its sensitive/production data!

diff preview

How diff.txt will look like

How do I convert from a string to an integer in Visual Basic?

Use

Convert.toInt32(txtPrice.Text)

This is assuming VB.NET.

Judging by the name "txtPrice", you really don't want an Integer but a Decimal. So instead use:

Convert.toDecimal(txtPrice.Text)

If this is the case, be sure whatever you assign this to is Decimal not an Integer.

Converting SVG to PNG using C#

you can use altsoft xml2pdf lib for this

Export a graph to .eps file with R

Another way is to use Cairographics-based SVG, PDF and PostScript Graphics Devices. This way you don't need to setEPS()

cairo_ps("image.eps")
plot(1, 10)
dev.off()

CSS to hide INPUT BUTTON value text

color:transparent;  /* For FF */
*padding-left:1000px ;  /* FOR IE6,IE7 */

Converting HTML to PDF using PHP?

If you wish to create a pdf from php, pdflib will help you (as some others suggested).

Else, if you want to convert an HTML page to PDF via PHP, you'll find a little trouble outta here.. For 3 years I've been trying to do it as best as I can.

So, the options I know are:

DOMPDF : php class that wraps the html and builds the pdf. Works good, customizable (if you know php), based on pdflib, if I remember right it takes even some CSS. Bad news: slow when the html is big or complex.

HTML2PS: same as DOMPDF, but this one converts first to a .ps (ghostscript) file, then, to whatever format you need (pdf, jpg, png). For me is little better than dompdf, but has the same speed problem.. but, better compatibility with CSS.

Those two are php classes, but if you can install some software on the server, and access it throught passthru() or system(), give a look to these too:

wkhtmltopdf: based on webkit (safari's wrapper), is really fast and powerful.. seems like this is the best one (atm) for converting html pages to pdf on the fly; taking only 2 seconds for a 3 page xHTML document with CSS2. It is a recent project, anyway, the google.code page is often updated.

htmldoc : This one is a tank, it never really stops/crashes.. the project looks dead since 2007, but anyway if you don't need CSS compatibility this can be nice for you.

How to create a DataFrame from a text file in Spark

You can read a file to have an RDD and then assign schema to it. Two common ways to creating schema are either using a case class or a Schema object [my preferred one]. Follows the quick snippets of code that you may use.

Case Class approach

case class Test(id:String,name:String)
val myFile = sc.textFile("file.txt")
val df= myFile.map( x => x.split(";") ).map( x=> Test(x(0),x(1)) ).toDF()

Schema Approach

import org.apache.spark.sql.types._
val schemaString = "id name"
val fields = schemaString.split(" ").map(fieldName => StructField(fieldName, StringType, nullable=true))
val schema = StructType(fields)

val dfWithSchema = sparkSess.read.option("header","false").schema(schema).csv("file.txt")
dfWithSchema.show()

The second one is my preferred approach since case class has a limitation of max 22 fields and this will be a problem if your file has more than 22 fields!

Return in Scala

Use case match for early return purpose. It will force you to declare all return branches explicitly, preventing the careless mistake of forgetting to write return somewhere.

Subtracting Dates in Oracle - Number or Interval Datatype?

Ok, I don't normally answer my own questions but after a bit of tinkering, I have figured out definitively how Oracle stores the result of a DATE subtraction.

When you subtract 2 dates, the value is not a NUMBER datatype (as the Oracle 11.2 SQL Reference manual would have you believe). The internal datatype number of a DATE subtraction is 14, which is a non-documented internal datatype (NUMBER is internal datatype number 2). However, it is actually stored as 2 separate two's complement signed numbers, with the first 4 bytes used to represent the number of days and the last 4 bytes used to represent the number of seconds.

An example of a DATE subtraction resulting in a positive integer difference:

select date '2009-08-07' - date '2008-08-08' from dual;

Results in:

DATE'2009-08-07'-DATE'2008-08-08'
---------------------------------
                              364

select dump(date '2009-08-07' - date '2008-08-08') from dual;

DUMP(DATE'2009-08-07'-DATE'2008
-------------------------------
Typ=14 Len=8: 108,1,0,0,0,0,0,0

Recall that the result is represented as a 2 seperate two's complement signed 4 byte numbers. Since there are no decimals in this case (364 days and 0 hours exactly), the last 4 bytes are all 0s and can be ignored. For the first 4 bytes, because my CPU has a little-endian architecture, the bytes are reversed and should be read as 1,108 or 0x16c, which is decimal 364.

An example of a DATE subtraction resulting in a negative integer difference:

select date '1000-08-07' - date '2008-08-08' from dual;

Results in:

DATE'1000-08-07'-DATE'2008-08-08'
---------------------------------
                          -368160

select dump(date '1000-08-07' - date '2008-08-08') from dual;

DUMP(DATE'1000-08-07'-DATE'2008-08-0
------------------------------------
Typ=14 Len=8: 224,97,250,255,0,0,0,0

Again, since I am using a little-endian machine, the bytes are reversed and should be read as 255,250,97,224 which corresponds to 11111111 11111010 01100001 11011111. Now since this is in two's complement signed binary numeral encoding, we know that the number is negative because the leftmost binary digit is a 1. To convert this into a decimal number we would have to reverse the 2's complement (subtract 1 then do the one's complement) resulting in: 00000000 00000101 10011110 00100000 which equals -368160 as suspected.

An example of a DATE subtraction resulting in a decimal difference:

select to_date('08/AUG/2004 14:00:00', 'DD/MON/YYYY HH24:MI:SS'
 - to_date('08/AUG/2004 8:00:00', 'DD/MON/YYYY HH24:MI:SS') from dual;

TO_DATE('08/AUG/200414:00:00','DD/MON/YYYYHH24:MI:SS')-TO_DATE('08/AUG/20048:00:
--------------------------------------------------------------------------------
                                                                             .25

The difference between those 2 dates is 0.25 days or 6 hours.

select dump(to_date('08/AUG/2004 14:00:00', 'DD/MON/YYYY HH24:MI:SS')
 - to_date('08/AUG/2004 8:00:00', 'DD/MON/YYYY HH24:MI:SS')) from dual;

DUMP(TO_DATE('08/AUG/200414:00:
-------------------------------
Typ=14 Len=8: 0,0,0,0,96,84,0,0

Now this time, since the difference is 0 days and 6 hours, it is expected that the first 4 bytes are 0. For the last 4 bytes, we can reverse them (because CPU is little-endian) and get 84,96 = 01010100 01100000 base 2 = 21600 in decimal. Converting 21600 seconds to hours gives you 6 hours which is the difference which we expected.

Hope this helps anyone who was wondering how a DATE subtraction is actually stored.


You get the syntax error because the date math does not return a NUMBER, but it returns an INTERVAL:

SQL> SELECT DUMP(SYSDATE - start_date) from test;

DUMP(SYSDATE-START_DATE)
-------------------------------------- 
Typ=14 Len=8: 188,10,0,0,223,65,1,0

You need to convert the number in your example into an INTERVAL first using the NUMTODSINTERVAL Function

For example:

SQL> SELECT (SYSDATE - start_date) DAY(5) TO SECOND from test;

(SYSDATE-START_DATE)DAY(5)TOSECOND
----------------------------------
+02748 22:50:04.000000

SQL> SELECT (SYSDATE - start_date) from test;

(SYSDATE-START_DATE)
--------------------
           2748.9515

SQL> select NUMTODSINTERVAL(2748.9515, 'day') from dual;

NUMTODSINTERVAL(2748.9515,'DAY')
--------------------------------
+000002748 22:50:09.600000000

SQL>

Based on the reverse cast with the NUMTODSINTERVAL() function, it appears some rounding is lost in translation.

Use jQuery to navigate away from page

window.location = myUrl;

Anyway, this is not jQuery: it's plain javascript

CSS Animation and Display None

CSS (or jQuery, for that matter) can't animate between display: none; and display: block;. Worse yet: it can't animate between height: 0 and height: auto. So you need to hard code the height (if you can't hard code the values then you need to use javascript, but this is an entirely different question);

#main-image{
    height: 0;
    overflow: hidden;
    background: red;
   -prefix-animation: slide 1s ease 3.5s forwards;
}

@-prefix-keyframes slide {
  from {height: 0;}
  to {height: 300px;}
}

You mention that you're using Animate.css, which I'm not familiar with, so this is a vanilla CSS.

You can see a demo here: http://jsfiddle.net/duopixel/qD5XX/

Pass arguments into C program from command line

Instead of getopt(), you may also consider using argp_parse() (an alternative interface to the same library).

From libc manual:

getopt is more standard (the short-option only version of it is a part of the POSIX standard), but using argp_parse is often easier, both for very simple and very complex option structures, because it does more of the dirty work for you.

But I was always happy with the standard getopt.

N.B. GNU getopt with getopt_long is GNU LGPL.

Percentage width in a RelativeLayout

I have solved this creating a custom View:

public class FractionalSizeView extends View {
  public FractionalSizeView(Context context, AttributeSet attrs) {
    super(context, attrs);
  }

  public FractionalSizeView(Context context, AttributeSet attrs, int defStyle) {
    super(context, attrs, defStyle);
  }

  @Override
  protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
    int width = MeasureSpec.getSize(widthMeasureSpec);
    setMeasuredDimension(width * 70 / 100, 0);
  }
}

This is invisible strut I can use to align other views within RelativeLayout.

increase font size of hyperlink text html

There is a way simpler way. You put the href in a paragraph just created for that href. For example:

HREF name

Removing a list of characters in string

You can use the translate method.

s.translate(None, '!.;,')

Android error: Failed to install *.apk on device *: timeout

I have encountered the same problem and tried to change the ADB connection timeout. That did not work. I switched between my PC's USB ports (front -> back) and it fixed the problem!!!

How to open spss data files in excel?

I tried the below and it worked well,

Install Dimensions Data Model and OLE DB Access

and follow the below steps in excel

Data->Get External Data ->From Other sources -> From Data Connection Wizard -> Other/Advanced-> SPSS MR DM-2 OLE DB Provider-> Metadata type as SPSS File(SAV)-> SPSS data file in Metadata Location->Finish

How can I get the current user directory?

Messing around with environment variables or hard-coded parent folder offsets is never a good idea when there is a API to get the info you want, call SHGetSpecialFolderPath(...,CSIDL_PROFILE,...)

How to write a multiline command?

If you came here looking for an answer to this question but not exactly the way the OP meant, ie how do you get multi-line CMD to work in a single line, I have a sort of dangerous answer for you.

Trying to use this with things that actually use piping, like say findstr is quite problematic. The same goes for dealing with elses. But if you just want a multi-line conditional command to execute directly from CMD and not via a batch file, this should do work well.

Let's say you have something like this in a batch that you want to run directly in command prompt:

@echo off
for /r %%T IN (*.*) DO (
    if /i "%%~xT"==".sln" (
        echo "%%~T" is a normal SLN file, and not a .SLN.METAPROJ or .SLN.PROJ file
        echo Dumping SLN file contents
        type "%%~T"
    )
)

Now, you could use the line-continuation carat (^) and manually type it out like this, but warning, it's tedious and if you mess up you can learn the joy of typing it all out again.

Well, it won't work with just ^ thanks to escaping mechanisms inside of parentheses shrug At least not as-written. You actually would need to double up the carats like so:

@echo off ^
More? for /r %T IN (*.sln) DO (^^
More? if /i "%~xT"==".sln" (^^
More? echo "%~T" is a normal SLN file, and not a .SLN.METAPROJ or .SLN.PROJ file^^
More? echo Dumping SLN file contents^^
More? type "%~T"))

Instead, you can be a dirty sneaky scripter from the wrong side of the tracks that don't need no carats by swapping them out for a single pipe (|) per continuation of a loop/expression:

@echo off
for /r %T IN (*.sln) DO if /i "%~xT"==".sln" echo "%~T" is a normal SLN file, and not a .SLN.METAPROJ or .SLN.PROJ file | echo Dumping SLN file contents | type "%~T"

DTO pattern: Best way to copy properties between two objects

You can use reflection to find all the get methods in your DAO objects and call the equivalent set method in the DTO. This will only work if all such methods exist. It should be easy to find example code for this.

How can I insert values into a table, using a subquery with more than one result?

INSERT INTO prices (group, id, price)
  SELECT 7, articleId, 1.50 FROM article WHERE name LIKE 'ABC%'

What is the difference between tinyint, smallint, mediumint, bigint and int in MySQL?

When it gets to real world usage of these datatypes, it is very important that you understand that using certain integer types could just be an overkill or under used. For example, using integer datatype for employeeCount in a table say employee could be an overkill since it supports a range of integer values from ~ negative 2 billion to positive 2 billion or zero to approximately 4 billion (unsigned). So, even if you consider one of the US biggest employer such as Walmart with roughly about 2.2 million employees using an integer datatype for the employeeCount column would be unnecessary. In such a case you use mediumint (that supports from 0 to 16 million (unsigned)) for example. Having said that if your range is expected to be unusually large you might consider bigint which as you can see from Daniel's notes supports a range larger than I care to decipher.

How can I get the browser's scrollbar sizes?

Here's the more concise and easy to read solution based on offset width difference:

function getScrollbarWidth(): number {

  // Creating invisible container
  const outer = document.createElement('div');
  outer.style.visibility = 'hidden';
  outer.style.overflow = 'scroll'; // forcing scrollbar to appear
  outer.style.msOverflowStyle = 'scrollbar'; // needed for WinJS apps
  document.body.appendChild(outer);

  // Creating inner element and placing it in the container
  const inner = document.createElement('div');
  outer.appendChild(inner);

  // Calculating difference between container's full width and the child width
  const scrollbarWidth = (outer.offsetWidth - inner.offsetWidth);

  // Removing temporary elements from the DOM
  outer.parentNode.removeChild(outer);

  return scrollbarWidth;

}

See the JSFiddle.

How to store token in Local or Session Storage in Angular 2?

Adding onto Bojan Kogoj's answer:

In your app.module.ts, add a new provider for storage.

@NgModule({
   providers: [
      { provide: Storage, useValue: localStorage }
   ],
   imports:[],
   declarations:[]
})

And then you can use DI to get it wherever you need it.

 @Injectable({
    providedIn:'root'
 })
 export class StateService {
    constructor(private storage: Storage) { }
 }

Undefined reference to vtable

What is a vtable?

It might be useful to know what the error message is talking about before trying to fix it. I'll start at a high level, then work down to some more details. That way people can skip ahead once they are comfortable with their understanding of vtables. …and there goes a bunch of people skipping ahead right now. :) For those sticking around:

A vtable is basically the most common implementation of polymorphism in C++. When vtables are used, every polymorphic class has a vtable somewhere in the program; you can think of it as a (hidden) static data member of the class. Every object of a polymorphic class is associated with the vtable for its most-derived class. By checking this association, the program can work its polymorphic magic. Important caveat: a vtable is an implementation detail. It is not mandated by the C++ standard, even though most (all?) C++ compilers use vtables to implement polymorphic behavior. The details I am presenting are either typical or reasonable approaches. Compilers are allowed to deviate from this!

Each polymorphic object has a (hidden) pointer to the vtable for the object's most-derived class (possibly multiple pointers, in the more complex cases). By looking at the pointer, the program can tell what the "real" type of an object is (except during construction, but let's skip that special case). For example, if an object of type A does not point to the vtable of A, then that object is actually a sub-object of something derived from A.

The name "vtable" comes from "virtual function table". It is a table that stores pointers to (virtual) functions. A compiler chooses its convention for how the table is laid out; a simple approach is to go through the virtual functions in the order they are declared within class definitions. When a virtual function is called, the program follows the object's pointer to a vtable, goes to the entry associated with the desired function, then uses the stored function pointer to invoke the correct function. There are various tricks for making this work, but I won't go into those here.

Where/when is a vtable generated?

A vtable is automatically generated (sometimes called "emitted") by the compiler. A compiler could emit a vtable in every translation unit that sees a polymorphic class definition, but that would usually be unnecessary overkill. An alternative (used by gcc, and probably by others) is to pick a single translation unit in which to place the vtable, similar to how you would pick a single source file in which to put a class' static data members. If this selection process fails to pick any translation units, then the vtable becomes an undefined reference. Hence the error, whose message is admittedly not particularly clear.

Similarly, if the selection process does pick a translation unit, but that object file is not provided to the linker, then the vtable becomes an undefined reference. Unfortunately, the error message can be even less clear in this case than in the case where the selection process failed. (Thanks to the answerers who mentioned this possibility. I probably would have forgotten it otherwise.)

The selection process used by gcc makes sense if we start with the tradition of devoting a (single) source file to each class that needs one for its implementation. It would be nice to emit the vtable when compiling that source file. Let's call that our goal. However, the selection process needs to work even if this tradition is not followed. So instead of looking for the implementation of the entire class, let's look for the implementation of a specific member of the class. If tradition is followed – and if that member is in fact implemented – then this achieves the goal.

The member selected by gcc (and potentially by other compilers) is the first non-inline virtual function that is not pure virtual. If you are part of the crowd that declares constructors and destructors before other member functions, then that destructor has a good chance of being selected. (You did remember to make the destructor virtual, right?) There are exceptions; I'd expect that the most common exceptions are when an inline definition is provided for the destructor and when the default destructor is requested (using "= default").

The astute might notice that a polymorphic class is allowed to provide inline definitions for all of its virtual functions. Doesn't that cause the selection process to fail? It does in older compilers. I've read that the latest compilers have addressed this situation, but I do not know relevant version numbers. I could try looking this up, but it's easier to either code around it or wait for the compiler to complain.

In summary, there are three key causes of the "undefined reference to vtable" error:

  1. A member function is missing its definition.
  2. An object file is not being linked.
  3. All virtual functions have inline definitions.

These causes are by themselves insufficient to cause the error on their own. Rather, these are what you would address to resolve the error. Do not expect that intentionally creating one of these situations will definitely produce this error; there are other requirements. Do expect that resolving these situations will resolve this error.

(OK, number 3 might have been sufficient when this question was asked.)

How to fix the error?

Welcome back people skipping ahead! :)

  1. Look at your class definition. Find the first non-inline virtual function that is not pure virtual (not "= 0") and whose definition you provide (not "= default").
    • If there is no such function, try modifying your class so there is one. (Error possibly resolved.)
    • See also the answer by Philip Thomas for a caveat.
  2. Find the definition for that function. If it is missing, add it! (Error possibly resolved.)
  3. Check your link command. If it does not mention the object file with that function's definition, fix that! (Error possibly resolved.)
  4. Repeat steps 2 and 3 for each virtual function, then for each non-virtual function, until the error is resolved. If you're still stuck, repeat for each static data member.

Example
The details of what to do can vary, and sometimes branch off into separate questions (like What is an undefined reference/unresolved external symbol error and how do I fix it?). I will, though, provide an example of what to do in a specific case that might befuddle newer programmers.

Step 1 mentions modifying your class so that it has a function of a certain type. If the description of that function went over your head, you might be in the situation I intend to address. Keep in mind that this is a way to accomplish the goal; it is not the only way, and there easily could be better ways in your specific situation. Let's call your class A. Is your destructor declared (in your class definition) as either

virtual ~A() = default;

or

virtual ~A() {}

? If so, two steps will change your destructor into the type of function we want. First, change that line to

virtual ~A();

Second, put the following line in a source file that is part of your project (preferably the file with the class implementation, if you have one):

A::~A() {}

That makes your (virtual) destructor non-inline and not generated by the compiler. (Feel free to modify things to better match your code formatting style, such as adding a header comment to the function definition.)

How to start up spring-boot application via command line?

Run Spring Boot app using Maven

You can also use Maven plugin to run your Spring Boot app. Use the below example to run your Spring Boot app with Maven plugin:

mvn spring-boot:run

Run Spring Boot App with Gradle

And if you use Gradle you can run the Spring Boot app with the following command:

gradle bootRun

How can I parse a local JSON file from assets folder into a ListView?

Using OKIO

public static String readJsonFromAssets(Context context, String filePath) {
    
        try {
            InputStream input = context.getAssets().open(filePath);
            BufferedSource source = Okio.buffer(Okio.source(input));
            return source.readByteString().string(Charset.forName("utf-8"));
        } catch (IOException e) {
            e.printStackTrace();
        }
    
        return null;
}

and then...

String data = readJsonFromAssets(context, "json/some.json"); //here is my file inside the folder assets/json/some.json

Type reviewType = new TypeToken<List<Object>>() {}.getType();

if (data != null) {
    Object object = new Gson().fromJson(data, reviewType);
}

Set maxlength in Html Textarea

resize:none; This property fix your text area and bound it. you use this css property id your textarea.gave text area an id and on the behalf of that id you can use this css property.

Accessing dictionary value by index in python

Standard Python dictionaries are inherently unordered, so what you're asking to do doesn't really make sense.

If you really, really know what you're doing, use

value_at_index = dic.values()[index]

Bear in mind that adding or removing an element can potentially change the index of every other element.

SQL Insert Query Using C#

public static string textDataSource = "Data Source=localhost;Initial 
Catalog=TEST_C;User ID=sa;Password=P@ssw0rd";
public static bool ExtSql(string sql) {
    SqlConnection cnn;
    SqlCommand cmd;
    cnn = new SqlConnection(textDataSource);
    cmd = new SqlCommand(sql, cnn);
    try {
        cnn.Open();
        cmd.ExecuteNonQuery();
        cnn.Close();
        return true;
    }
    catch (Exception) {
        return false;
    }
    finally {
        cmd.Dispose();
        cnn = null;
        cmd = null; 
    }
}

Change color of bootstrap navbar on hover link?

_x000D_
_x000D_
.navbar-default .navbar-nav > li > a{_x000D_
  color: #e9b846;_x000D_
}_x000D_
.navbar-default .navbar-nav > li > a:hover{_x000D_
  background-color: #e9b846;_x000D_
  color: #FFFFFF;_x000D_
}
_x000D_
_x000D_
_x000D_

Set style for TextView programmatically

I have only tested with EditText but you can use the method

public void setBackgroundResource (int resid)

to apply a style defined in an XML file.

Sine this method belongs to View I believe it will work with any UI element.

regards.

The name 'InitializeComponent' does not exist in the current context

You might get this error when you import a class from another project, or change the path of the xaml file, or the namespace of either the xaml or behind .cs file.

One: It might have a namespace that is not the same as what you have in you new project

namespace TrainerB.MVC.Forms
{
     public partial class AboutDeveloper : ContentPage
     {
          public AboutDeveloper()
          {
               InitializeComponent();
          }
     }
}

As you can see the name space in the imported file begins with the old project name: "TrainerB", but your new project might have a different name, so just change it to the correct new project name, in both the .xaml file and the behind .cs file.

Two:

change the properties of the .xaml file to:

Build Action: Embedded Resource

Custom Tool: MSBuild:UpdateDesignTimeXaml

Xaml file properties

Xaml Namespace Correcting 01

Xaml Namespace Correcting 02

How can I print variable and string on same line in Python?

Two more

The First one

>>> births = str(5)
>>> print("there are " + births + " births.")
there are 5 births.

When adding strings, they concatenate.

The Second One

Also the format (Python 2.6 and newer) method of strings is probably the standard way:

>>> births = str(5)
>>>
>>> print("there are {} births.".format(births))
there are 5 births.

This format method can be used with lists as well

>>> format_list = ['five', 'three']
>>> # * unpacks the list:
>>> print("there are {} births and {} deaths".format(*format_list))  
there are five births and three deaths

or dictionaries

>>> format_dictionary = {'births': 'five', 'deaths': 'three'}
>>> # ** unpacks the dictionary
>>> print("there are {births} births, and {deaths} deaths".format(**format_dictionary))
there are five births, and three deaths

Dealing with timestamps in R

You want the (standard) POSIXt type from base R that can be had in 'compact form' as a POSIXct (which is essentially a double representing fractional seconds since the epoch) or as long form in POSIXlt (which contains sub-elements). The cool thing is that arithmetic etc are defined on this -- see help(DateTimeClasses)

Quick example:

R> now <- Sys.time()
R> now
[1] "2009-12-25 18:39:11 CST"
R> as.numeric(now)
[1] 1.262e+09
R> now + 10  # adds 10 seconds
[1] "2009-12-25 18:39:21 CST"
R> as.POSIXlt(now)
[1] "2009-12-25 18:39:11 CST"
R> str(as.POSIXlt(now))
 POSIXlt[1:9], format: "2009-12-25 18:39:11"
R> unclass(as.POSIXlt(now))
$sec
[1] 11.79

$min
[1] 39

$hour
[1] 18

$mday
[1] 25

$mon
[1] 11

$year
[1] 109

$wday
[1] 5

$yday
[1] 358

$isdst
[1] 0

attr(,"tzone")
[1] "America/Chicago" "CST"             "CDT"            
R> 

As for reading them in, see help(strptime)

As for difference, easy too:

R> Jan1 <- strptime("2009-01-01 00:00:00", "%Y-%m-%d %H:%M:%S")
R> difftime(now, Jan1, unit="week")
Time difference of 51.25 weeks
R> 

Lastly, the zoo package is an extremely versatile and well-documented container for matrix with associated date/time indices.

facebook: permanent Page Access Token?

In addition to the recommended steps in the Vlasec answer, you can use:

  • Graph API explorer to make the queries, e.g. /{pageId}?fields=access_token&access_token=THE_ACCESS_TOKEN_PROVIDED_BY_GRAPH_EXPLORER
  • Access Token Debugger to get information about the access token.

Why is "using namespace std;" considered bad practice?

Here is an example showing how using namespace std; can lead to name clash problems:

Unable to define a global variable in C++

In the example a very generic algorithm name (std::count) name clashes with a very reasonable variable name (count).

Simple example for Intent and Bundle

Basically this is what you need to do:
in the first activity:

Intent intent = new Intent();
intent.setAction(this, SecondActivity.class);
intent.putExtra(tag, value);
startActivity(intent);

and in the second activtiy:

Intent intent = getIntent();
intent.getBooleanExtra(tag, defaultValue);
intent.getStringExtra(tag, defaultValue);
intent.getIntegerExtra(tag, defaultValue);

one of the get-functions will give return you the value, depending on the datatype you are passing through.

Android EditText delete(backspace) key event

My problem was, that I had custom Textwatcher, so I didn't want to add OnKeyListener to an EditText as well as I didn't want to create custom EditText. I wanted to detect if backspace was pressed in my afterTextChanged method, so I shouldn't trigger my event.

This is how I solved this. Hope it would be helpful for someone.

public class CustomTextWatcher extends AfterTextChangedTextWatcher {

private boolean backspacePressed;

@Override
public void afterTextChanged(Editable s) {
    if (!backspacePressed) {
        triggerYourEvent();
    }
}

@Override
public void onTextChanged(CharSequence s, int start, int before, int count) {
    super.onTextChanged(s, start, before, count);
    backspacePressed = count == 0; //if count == 0, backspace is pressed
}
}

How to make <input type="date"> supported on all browsers? Any alternatives?

Just use <script src="modernizr.js"></script> in the <head> section, and the script will add classes which help you to separate the two cases: if it's supported by the current browser, or if it's not.

Plus follow the links posted in this thread. It will help you: HTML5 input type date, color, range support in Firefox and Internet Explorer

Replacing &nbsp; from javascript dom text node

var text = "&quot;&nbsp;&amp;&lt;&gt;";
text = text.replaceHtmlEntites();

String.prototype.replaceHtmlEntites = function() {
var s = this;
var translate_re = /&(nbsp|amp|quot|lt|gt);/g;
var translate = {"nbsp": " ","amp" : "&","quot": "\"","lt"  : "<","gt"  : ">"};
return ( s.replace(translate_re, function(match, entity) {
  return translate[entity];
}) );
};

try this.....this worked for me

SQLException : String or binary data would be truncated

With Linq To SQL I debugged by logging the context, eg. Context.Log = Console.Out Then scanned the SQL to check for any obvious errors, there were two:

-- @p46: Input Char (Size = -1; Prec = 0; Scale = 0) [some long text value1]
-- @p8: Input Char (Size = -1; Prec = 0; Scale = 0) [some long text value2]

the last one I found by scanning the table schema against the values, the field was nvarchar(20) but the value was 22 chars

-- @p41: Input NVarChar (Size = 4000; Prec = 0; Scale = 0) [1234567890123456789012]

gitx How do I get my 'Detached HEAD' commits back into master

If checkout master was the last thing you did, then the reflog entry HEAD@{1} will contain your commits (otherwise use git reflog or git log -p to find them). Use git merge HEAD@{1} to fast forward them into master.

EDIT:

As noted in the comments, Git Ready has a great article on this.

git reflog and git reflog --all will give you the commit hashes of the mis-placed commits.

Git Ready: Reflog, Your Safety Net

Source: http://gitready.com/intermediate/2009/02/09/reflog-your-safety-net.html

Show an image preview before upload

Here I did with jQuery using FileReader API.

Html Markup:

<input id="fileUpload" type="file" multiple />
<div id="image-holder"></div>

jQuery:

Here in jQuery code,first I check for file extension. i.e valid image file to be processed, then will check whether the browser support FileReader API is yes then only processed else display respected message

$("#fileUpload").on('change', function () {

     //Get count of selected files
     var countFiles = $(this)[0].files.length;

     var imgPath = $(this)[0].value;
     var extn = imgPath.substring(imgPath.lastIndexOf('.') + 1).toLowerCase();
     var image_holder = $("#image-holder");
     image_holder.empty();

     if (extn == "gif" || extn == "png" || extn == "jpg" || extn == "jpeg") {
         if (typeof (FileReader) != "undefined") {

             //loop for each file selected for uploaded.
             for (var i = 0; i < countFiles; i++) {

                 var reader = new FileReader();
                 reader.onload = function (e) {
                     $("<img />", {
                         "src": e.target.result,
                             "class": "thumb-image"
                     }).appendTo(image_holder);
                 }

                 image_holder.show();
                 reader.readAsDataURL($(this)[0].files[i]);
             }

         } else {
             alert("This browser does not support FileReader.");
         }
     } else {
         alert("Pls select only images");
     }
 });

Detailed Article: How to Preview Image before upload it, jQuery, HTML5 FileReader() with Live Demo

How do I redirect to the previous action in ASP.NET MVC?

You could return to the previous page by using ViewBag.ReturnUrl property.

What is the difference between join and merge in Pandas?

  • Join: Default Index (If any same column name then it will throw an error in default mode because u have not defined lsuffix or rsuffix))
df_1.join(df_2)
  • Merge: Default Same Column Names (If no same column name it will throw an error in default mode)
df_1.merge(df_2)
  • on parameter has different meaning in both cases
df_1.merge(df_2, on='column_1')

df_1.join(df_2, on='column_1') // It will throw error
df_1.join(df_2.set_index('column_1'), on='column_1')

PHP include relative path

function relativepath($to){
    $a=explode("/",$_SERVER["PHP_SELF"] );
    $index= array_search("$to",$a);
    $str=""; 
    for ($i = 0; $i < count($a)-$index-2; $i++) {
        $str.= "../";
    }
    return $str;
    }

Here is the best solution i made about that, you just need to specify at which level you want to stop, but the problem is that you have to use this folder name one time.

App.Config Transformation for projects which are not Web Projects in Visual Studio?

So I ended up taking a slightly different approach. I followed Dan's steps through step 3, but added another file: App.Base.Config. This file contains the configuration settings you want in every generated App.Config. Then I use BeforeBuild (with Yuri's addition to TransformXml) to transform the current configuration with the Base config into the App.config. The build process then uses the transformed App.config as normal. However, one annoyance is you kind of want to exclude the ever-changing App.config from source control afterwards, but the other config files are now dependent upon it.

  <UsingTask TaskName="TransformXml" AssemblyFile="$(MSBuildExtensionsPath)\Microsoft\VisualStudio\v$(VisualStudioVersion)\Web\Microsoft.Web.Publishing.Tasks.dll" />
  <Target Name="BeforeBuild" Condition="exists('app.$(Configuration).config')">
    <TransformXml Source="App.Base.config" Transform="App.$(Configuration).config" Destination="App.config" />
  </Target>

Changing Underline color

Problem with border-bottom is the extra distance between the text and the line. Problem with text-decoration-color is lack of browser support. Therefore my solution is the use of a background-image with a line. This supports any markup, color(s) and style of the line. top (12px in my example) is dependent on line-height of your text.

 u {
    text-decoration: none;
    background: transparent url(blackline.png) repeat-x 0px 12px;
}

How does cookie based authentication work?

Cookie-Based Authentication

Cookies based Authentication works normally in these 4 steps-

  1. The user provides a username and password in the login form and clicks Log In.
  2. After the request is made, the server validate the user on the backend by querying in the database. If the request is valid, it will create a session by using the user information fetched from the database and store them, for each session a unique id called session Id is created ,by default session Id is will be given to client through the Browser.
  3. Browser will submit this session Id on each subsequent requests, the session ID is verified against the database, based on this session id website will identify the session belonging to which client and then give access the request.

  4. Once a user logs out of the app, the session is destroyed both client-side and server-side.

How to set Spring profile from system variable?

You can set the spring profile by supplying -Dspring.profiles.active=<env>

For java files in source(src) directory, you can use by System.getProperty("spring.profiles.active")

For java files in test directory you can supply

  • SPRING_PROFILES_ACTIVE to <env>

OR

Since, "environment", "jvmArgs" and "systemProperties" are ignored for the "test" task. In root build.gradle add a task to set jvm property and environment variable.

test {
    def profile = System.properties["spring.profiles.active"]
    systemProperty "spring.profiles.active",profile
    environment "SPRING.PROFILES_ACTIVE", profile
    println "Running ${project} tests with profile: ${profile}"
}

Check if an HTML input element is empty or has no value entered by user

getElementById will return false if the element was not found in the DOM.

var el = document.getElementById("customx");
if (el !== null && el.value === "")
{
  //The element was found and the value is empty.
}

Can't get Python to import from a different folder

My preferred way is to have __init__.py on every directory that contains modules that get used by other modules, and in the entry point, override sys.path as below:

def get_path(ss):
  return os.path.join(os.path.dirname(__file__), ss)
sys.path += [
  get_path('Server'), 
  get_path('Models')
]

This makes the files in specified directories visible for import, and I can import user from Server.py.

Is it possible to set UIView border properties from interface builder?

If you want to save time, just use two UIViews on top of each other, the one at the back being the border color, and the one in front smaller, giving the bordered effect. I don't think this is an elegant solution either, but if Apple cared a little more then you shouldn't have to do this.

How can I append a string to an existing field in MySQL?

You need to use the CONCAT() function in MySQL for string concatenation:

UPDATE categories SET code = CONCAT(code, '_standard') WHERE id = 1;

set the iframe height automatically

If you a framework like Bootstrap you can make any iframe video responsive by using this snippet:

<div class="embed-responsive embed-responsive-16by9">
    <iframe class="embed-responsive-item" src="vid.mp4" allowfullscreen></iframe>
</div>

Removing all empty elements from a hash / YAML?

works for both hashes and arrays

module Helpers
  module RecursiveCompact
    extend self

    def recursive_compact(hash_or_array)
      p = proc do |*args|
        v = args.last
        v.delete_if(&p) if v.respond_to? :delete_if
        v.nil? || v.respond_to?(:"empty?") && v.empty?
      end

      hash_or_array.delete_if(&p)
    end
  end
end

P.S. based on someones answer, cant find

usage - Helpers::RecursiveCompact.recursive_compact(something)

How to make the Facebook Like Box responsive?

None of the css trick worked for me (in my case the fb-like box was pulled right with "float:right"). However, what worked without any additional tricks is an IFRAME version of the button code. I.e.:

<iframe src="//www.facebook.com/plugins/like.php?href=..." 
        scrolling="no" frameborder="0" 
        style="border:none; overflow:hidden; width:71px; height:21px;" 
        allowTransparency="true">
</iframe>

(Note custom width in style, and no need to include additional javascript.)

How to add element in List while iterating in java?

You can't use a foreach statement for that. The foreach is using internally an iterator:

The iterators returned by this class's iterator and listIterator methods are fail-fast: if the list is structurally modified at any time after the iterator is created, in any way except through the iterator's own remove or add methods, the iterator will throw a ConcurrentModificationException.

(From ArrayList javadoc)

In the foreach statement you don't have access to the iterator's add method and in any case that's still not the type of add that you want because it does not append at the end. You'll need to traverse the list manually:

int listSize = list.size();
for(int i = 0; i < listSize; ++i)
  list.add("whatever");

Note that this is only efficient for Lists that allow random access. You can check for this feature by checking whether the list implements the RandomAccess marker interface. An ArrayList has random access. A linked list does not.

How to replace negative numbers in Pandas Data Frame by zero

With lambda function

df['column'] = df['column'].apply(lambda x : x if x > 0 else 0)

Explanation of the UML arrows

enter image description here

enter image description here

I think these pictures are understandable.

How can I get the number of days between 2 dates in Oracle 11g?

I figured it out myself. I need

select extract(day from sysdate - to_date('2009-10-01', 'yyyy-mm-dd')) from dual

How can I declare and use Boolean variables in a shell script?

TL;DR

bool=true

if [ "$bool" = true ]

Issues with Miku's (original) answer

I do not recommend the accepted answer1. Its syntax is pretty, but it has some flaws.

Say we have the following condition.

if $var; then
  echo 'Muahahaha!'
fi

In the following cases2, this condition will evaluate to true and execute the nested command.

# Variable var not defined beforehand. Case 1
var=''  # Equivalent to var="".      # Case 2
var=                                 # Case 3
unset var                            # Case 4
var='<some valid command>'           # Case 5

Typically you only want your condition to evaluate to true when your "Boolean" variable, var in this example, is explicitly set to true. All the other cases are dangerously misleading!

The last case (#5) is especially naughty because it will execute the command contained in the variable (which is why the condition evaluates to true for valid commands3, 4).

Here is a harmless example:

var='echo this text will be displayed when the condition is evaluated'
if $var; then
  echo 'Muahahaha!'
fi

# Outputs:
# this text will be displayed when the condition is evaluated
# Muahahaha!

Quoting your variables is safer, e.g. if "$var"; then. In the above cases, you should get a warning that the command is not found. But we can still do better (see my recommendations at the bottom).

Also see Mike Holt's explanation of Miku's original answer.

Issues with Hbar's answer

This approach also has unexpected behavior.

var=false
if [ $var ]; then
  echo "This won't print, var is false!"
fi

# Outputs:
# This won't print, var is false!

You would expect the above condition to evaluate to false, thus never executing the nested statement. Surprise!

Quoting the value ("false"), quoting the variable ("$var"), or using test or [[ instead of [, do not make a difference.

What I do recommend:

Here are ways I recommend you check your "Booleans". They work as expected.

bool=true

if [ "$bool" = true ]; then
if [ "$bool" = "true" ]; then

if [[ "$bool" = true ]]; then
if [[ "$bool" = "true" ]]; then
if [[ "$bool" == true ]]; then
if [[ "$bool" == "true" ]]; then

if test "$bool" = true; then
if test "$bool" = "true"; then

They're all pretty much equivalent. You'll have to type a few more keystrokes than the approaches in the other answers5, but your code will be more defensive.


Footnotes

  1. Miku's answer has since been edited and no longer contains (known) flaws.
  2. Not an exhaustive list.
  3. A valid command in this context means a command that exists. It doesn't matter if the command is used correctly or incorrectly. E.g. man woman would still be considered a valid command, even if no such man page exists.
  4. For invalid (non-existent) commands, Bash will simply complain that the command wasn't found.
  5. If you care about length, the first recommendation is the shortest.

Generate Json schema from XML schema (XSD)

Copy your XML schema here & get the JSON schema code to the online tools which are available to generate JSON schema from XML schema.

How to check if a string contains only digits in Java

Using regular expressions is costly in terms of performance. Trying to parse string as a long value is inefficient and unreliable, and may be not what you need.

What I suggest is to simply check if each character is a digit, what can be efficiently done using Java 8 lambda expressions:

boolean isNumeric = someString.chars().allMatch(x -> Character.isDigit(x));

Can I prevent text in a div block from overflowing?

You can use the CSS property text-overflow to truncate long texts.

<div id="greetings">
  Hello universe!
</div>

#greetings
{
  width: 100px;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis; // This is where the magic happens
}

reference: http://makandracards.com/makandra/5883-use-css-text-overflow-to-truncate-long-texts

How to justify navbar-nav in Bootstrap 3

I know this is an old post but I would like share my solution. I spent several hours trying to make a justified navigation menu. You do not really need to modify anything in bootstrap css. Just need to add the correct class in the html.

   <nav class="nav navbar-default navbar-fixed-top">
        <div class="navbar-header">
            <button type="button" class="navbar-toggle collapsed" data-toggle="collapse" data-target="#collapsable-1" aria-expanded="false">
                <span class="sr-only">Toggle navigation</span>
                <span class="icon-bar"></span>
                <span class="icon-bar"></span>
                <span class="icon-bar"></span>
            </button>
            <a class="navbar-brand" href="#top">Brand Name</a>
        </div>
        <div class="collapse navbar-collapse" id="collapsable-1">
            <ul class="nav nav-justified">
                <li><a href="#about-me">About Me</a></li>
                <li><a href="#skills">Skills</a></li>
                <li><a href="#projects">Projects</a></li>
                <li><a href="#contact-me">Contact Me</a></li>
            </ul>
        </div>
    </nav>

This CSS code will simply remove the navbar-brand class when the screen reaches 768px.

media@(min-width: 768px){
   .navbar-brand{
        display: none;
    }
}

"%%" and "%/%" for the remainder and the quotient

I think it is because % has often be associated with the modulus operator in many programming languages.

It is the case, e.g., in C, C++, C# and Java, and many other languages which derive their syntax from C (C itself took it from B).

Getting data-* attribute for onclick event for an html element

Check if the data attribute is present, then do the stuff...

$('body').on('click', '.CLICK_BUTTON_CLASS', function (e) {
                        if(e.target.getAttribute('data-title')) {
                            var careerTitle = $(this).attr('data-title');
                            if (careerTitle.length > 0) $('.careerFormTitle').text(careerTitle);
                        }
                });

Converting Float to Dollars and Cents

Building on @JustinBarber's example and noting @eric.frederich's comment, if you want to format negative values like -$1,000.00 rather than $-1,000.00 and don't want to use locale:

def as_currency(amount):
    if amount >= 0:
        return '${:,.2f}'.format(amount)
    else:
        return '-${:,.2f}'.format(-amount)

Tensorflow set CUDA_VISIBLE_DEVICES within jupyter

You can set environment variables in the notebook using os.environ. Do the following before initializing TensorFlow to limit TensorFlow to first GPU.

import os
os.environ["CUDA_DEVICE_ORDER"]="PCI_BUS_ID"   # see issue #152
os.environ["CUDA_VISIBLE_DEVICES"]="0"

You can double check that you have the correct devices visible to TF

from tensorflow.python.client import device_lib
print device_lib.list_local_devices()

I tend to use it from utility module like notebook_util

import notebook_util
notebook_util.pick_gpu_lowest_memory()
import tensorflow as tf

Difference between InvariantCulture and Ordinal string comparison

Another handy difference (in English where accents are uncommon) is that an InvariantCulture comparison compares the entire strings by case-insensitive first, and then if necessary (and requested) distinguishes by case after first comparing only on the distinct letters. (You can also do a case-insensitive comparison, of course, which won't distinguish by case.) Corrected: Accented letters are considered to be another flavor of the same letters and the string is compared first ignoring accents and then accounting for them if the general letters all match (much as with differing case except not ultimately ignored in a case-insensitive compare). This groups accented versions of the otherwise same word near each other instead of completely separate at the first accent difference. This is the sort order you would typically find in a dictionary, with capitalized words appearing right next to their lowercase equivalents, and accented letters being near the corresponding unaccented letter.

An ordinal comparison compares strictly on the numeric character values, stopping at the first difference. This sorts capitalized letters completely separate from the lowercase letters (and accented letters presumably separate from those), so capitalized words would sort nowhere near their lowercase equivalents.

InvariantCulture also considers capitals to be greater than lower case, whereas Ordinal considers capitals to be less than lowercase (a holdover of ASCII from the old days before computers had lowercase letters, the uppercase letters were allocated first and thus had lower values than the lowercase letters added later).

For example, by Ordinal: "0" < "9" < "A" < "Ab" < "Z" < "a" < "aB" < "ab" < "z" < "Á" < "Áb" < "á" < "áb"

And by InvariantCulture: "0" < "9" < "a" < "A" < "á" < "Á" < "ab" < "aB" < "Ab" < "áb" < "Áb" < "z" < "Z"

What is the difference between primary, unique and foreign key constraints, and indexes?

Here are some reference for you:

Primary & foreign key Constraint.

Primary Key: A primary key is a field or combination of fields that uniquely identify a record in a table, so that an individual record can be located without confusion.

Foreign Key: A foreign key (sometimes called a referencing key) is a key used to link two tables together. Typically you take the primary key field from one table and insert it into the other table where it becomes a foreign key (it remains a primary key in the original table).

Index, on the other hand, is an attribute that you can apply on some columns so that the data retrieval done on those columns can be speed up.

Where is Maven's settings.xml located on Mac OS?

After I have downloaded the binary from apache site I, have placed the extracted folder in /Library
So now the location of the settings.xml file is in:

/Library/apache_maven_3.6.3/conf

TestNG ERROR Cannot find class in classpath

I had to make a jar file from my test classes and add it to my class path. Previously I added my test class file to class path and then I got above error. So I created a jar and added to classpath.

e.g

java -cp "my_jars/*" org.testng.TestNG testing.xml

How to get only filenames within a directory using c#?

You could use the DirectoryInfo and FileInfo classes.

//GetFiles on DirectoryInfo returns a FileInfo object.
var pdfFiles = new DirectoryInfo("C:\\Documents").GetFiles("*.pdf");

//FileInfo has a Name property that only contains the filename part.
var firstPdfFilename = pdfFiles[0].Name;

Not showing placeholder for input type="date" field

None of the solutions were working correctly for me on Chrome in iOS 12 and most of them are not tailored to cope with possible multiple date inputs on a page. I did the following, which basically creates a fake label over the date input and removes it on tap. I am also removing the fake label if viewport width is beyond 992px.

JS:

function addMobileDatePlaceholder() {
    if (window.matchMedia("(min-width: 992px)").matches) {
        $('input[type="date"]').next("span.date-label").remove();
        return false;
    }

    $('input[type="date"]').after('<span class="date-label" />');

    $('span.date-label').each(function() {
        var $placeholderText = $(this).prev('input[type="date"]').attr('placeholder');
        $(this).text($placeholderText);
    });

    $('input[type="date"]').on("click", function() {
        $(this).next("span.date-label").remove();
    });
}

CSS:

@media (max-width: 991px) {
    input[type="date"] {
        padding-left: calc(50% - 45px);
    }

    span.date-label {
        pointer-events: none;
        position: absolute;
        top: 2px;
        left: 50%;
        transform: translateX(-50%);
        text-align: center;
        height: 27px;
        width: 70%;
        padding-top: 5px;
    }
}

How to insert newline in string literal?

newer .net versions allow you to use $ in front of the literal which allows you to use variables inside like follows:

var x = $"Line 1{Environment.NewLine}Line 2{Environment.NewLine}Line 3";

How do I show the value of a #define at compile-time?

You could write a program that prints out BOOST_VERSION and compile and run it as part of your build system. Otherwise, I think you're out of luck.

How can I save a base64-encoded image to disk?

I think you are converting the data a bit more than you need to. Once you create the buffer with the proper encoding, you just need to write the buffer to the file.

var base64Data = req.rawBody.replace(/^data:image\/png;base64,/, "");

require("fs").writeFile("out.png", base64Data, 'base64', function(err) {
  console.log(err);
});

new Buffer(..., 'base64') will convert the input string to a Buffer, which is just an array of bytes, by interpreting the input as a base64 encoded string. Then you can just write that byte array to the file.

Update

As mentioned in the comments, req.rawBody is no longer a thing. If you are using express/connect then you should use the bodyParser() middleware and use req.body, and if you are doing this using standard Node then you need to aggregate the incoming data event Buffer objects and do this image data parsing in the end callback.

Arduino Tools > Serial Port greyed out

For a Windows solution I've found that disabling and re-enabling the Arduino in Device Manager, then restarting the Arduino IDE does the trick without fail (no unplugging necessary). Why this error occurs in the first place is beyond me. Perhaps the corresponding method for Linux will fix your problem.

Slightly related (not really), I had an issue with an AVR board a while back which was fixed by setting the device to a new COM port in the driver settings. Again, however you linux bunnies do it, I'm sure it'll be cookies and cream.

Cheers brother,

How to capitalize the first letter of text in a TextView in an Android Application

The accepted answer is good, but if you are using it to get values from a textView in android, it would be good to check if the string is empty. If the string is empty it would throw an exception.

private String capitizeString(String name){
    String captilizedString="";
    if(!name.trim().equals("")){
       captilizedString = name.substring(0,1).toUpperCase() + name.substring(1);
    }
    return captilizedString;
}

Keyboard shortcut to comment lines in Sublime Text 3

In Windows use ctrl + shift + : to comment for Python.

How to implement drop down list in flutter?

place the value inside the items.then it will work,

new DropdownButton<String>(
              items:_dropitems.map((String val){
                return DropdownMenuItem<String>(
                  value: val,
                  child: new Text(val),
                );
              }).toList(),
              hint:Text(_SelectdType),
              onChanged:(String val){
                _SelectdType= val;
                setState(() {});
                })

Python readlines() usage and efficient practice for reading

The short version is: The efficient way to use readlines() is to not use it. Ever.


I read some doc notes on readlines(), where people has claimed that this readlines() reads whole file content into memory and hence generally consumes more memory compared to readline() or read().

The documentation for readlines() explicitly guarantees that it reads the whole file into memory, and parses it into lines, and builds a list full of strings out of those lines.

But the documentation for read() likewise guarantees that it reads the whole file into memory, and builds a string, so that doesn't help.


On top of using more memory, this also means you can't do any work until the whole thing is read. If you alternate reading and processing in even the most naive way, you will benefit from at least some pipelining (thanks to the OS disk cache, DMA, CPU pipeline, etc.), so you will be working on one batch while the next batch is being read. But if you force the computer to read the whole file in, then parse the whole file, then run your code, you only get one region of overlapping work for the entire file, instead of one region of overlapping work per read.


You can work around this in three ways:

  1. Write a loop around readlines(sizehint), read(size), or readline().
  2. Just use the file as a lazy iterator without calling any of these.
  3. mmap the file, which allows you to treat it as a giant string without first reading it in.

For example, this has to read all of foo at once:

with open('foo') as f:
    lines = f.readlines()
    for line in lines:
        pass

But this only reads about 8K at a time:

with open('foo') as f:
    while True:
        lines = f.readlines(8192)
        if not lines:
            break
        for line in lines:
            pass

And this only reads one line at a time—although Python is allowed to (and will) pick a nice buffer size to make things faster.

with open('foo') as f:
    while True:
        line = f.readline()
        if not line:
            break
        pass

And this will do the exact same thing as the previous:

with open('foo') as f:
    for line in f:
        pass

Meanwhile:

but should the garbage collector automatically clear that loaded content from memory at the end of my loop, hence at any instant my memory should have only the contents of my currently processed file right ?

Python doesn't make any such guarantees about garbage collection.

The CPython implementation happens to use refcounting for GC, which means that in your code, as soon as file_content gets rebound or goes away, the giant list of strings, and all of the strings within it, will be freed to the freelist, meaning the same memory can be reused again for your next pass.

However, all those allocations, copies, and deallocations aren't free—it's much faster to not do them than to do them.

On top of that, having your strings scattered across a large swath of memory instead of reusing the same small chunk of memory over and over hurts your cache behavior.

Plus, while the memory usage may be constant (or, rather, linear in the size of your largest file, rather than in the sum of your file sizes), that rush of mallocs to expand it the first time will be one of the slowest things you do (which also makes it much harder to do performance comparisons).


Putting it all together, here's how I'd write your program:

for filename in os.listdir(input_dir):
    with open(filename, 'rb') as f:
        if filename.endswith(".gz"):
            f = gzip.open(fileobj=f)
        words = (line.split(delimiter) for line in f)
        ... my logic ...  

Or, maybe:

for filename in os.listdir(input_dir):
    if filename.endswith(".gz"):
        f = gzip.open(filename, 'rb')
    else:
        f = open(filename, 'rb')
    with contextlib.closing(f):
        words = (line.split(delimiter) for line in f)
        ... my logic ...

Limit text length to n lines using CSS

.class{
   word-break: break-word;
   overflow: hidden;
   text-overflow: ellipsis;
   display: -webkit-box;
   line-height: 16px; /* fallback */
   max-height: 32px; /* fallback */
   -webkit-line-clamp: 2; /* number of lines to show */
   -webkit-box-orient: vertical;
}

Why there is this "clear" class before footer?

Most likely, as mentioned by others, it is a class carrying the css values:

.clear{clear: both;} 

in order to prevent any more page elements from extending into the footer element. It is a quick and easy way of making sure that pages with columns of varying heights don't cause the footer to render oddly, by possibly setting its top position at the end of a shorter column.

In many cases it is not necessary, but if you are using best-practice standards it is a good idea to use, if you are floating page elements left and right. It functions with page elements similar to the way a horizontal rule works with text, to ensure proper and complete sepperation.

Difference between $(document.body) and $('body')

Outputwise both are equivalent. Though the second expression goes through a top down lookup from the DOM root. You might want to avoid the additional overhead (however minuscule it may be) if you already have document.body object in hand for JQuery to wrap over. See http://api.jquery.com/jQuery/ #Selector Context

How to parse a CSV in a Bash script?

A sed or awk solution would probably be shorter, but here's one for Perl:

perl -F/,/ -ane 'print if $F[<INDEX>] eq "<VALUE>"`

where <INDEX> is 0-based (0 for first column, 1 for 2nd column, etc.)

Set Font Color, Font Face and Font Size in PHPExcel

I recommend you start reading the documentation (4.6.18. Formatting cells). When applying a lot of formatting it's better to use applyFromArray() According to the documentation this method is also suppose to be faster when you're setting many style properties. There's an annex where you can find all the possible keys for this function.

This will work for you:

$phpExcel = new PHPExcel();

$styleArray = array(
    'font'  => array(
        'bold'  => true,
        'color' => array('rgb' => 'FF0000'),
        'size'  => 15,
        'name'  => 'Verdana'
    ));

$phpExcel->getActiveSheet()->getCell('A1')->setValue('Some text');
$phpExcel->getActiveSheet()->getStyle('A1')->applyFromArray($styleArray);

To apply font style to complete excel document:

 $styleArray = array(
   'font'  => array(
        'bold'  => true,
        'color' => array('rgb' => 'FF0000'),
        'size'  => 15,
        'name'  => 'Verdana'
    ));      
 $phpExcel->getDefaultStyle()
    ->applyFromArray($styleArray);

jquery get all input from specific form

Use HTML Form "elements" attribute:

$.each($("form").elements, function(){ 
    console.log($(this));
    });

Now it's not necessary to provide such names as "input, textarea, select ..." etc.

How to find keys of a hash?

I wanted to use the top rated answer above

Object.prototype.keys = function () ...

However when using in conjunction with the google maps API v3, google maps is non-functional.

for (var key in h) ...

works well.

Java java.sql.SQLException: Invalid column index on preparing statement

In date '?', the '?' is a literal string with value ?, not a parameter placeholder, so your query does not have any parameters. The date is a shorthand cast from (literal) string to date. You need to replace date '?' with ? to actually have a parameter.

Also if you know it is a date, then use setDate(..) and not setString(..) to set the parameter.

Returning IEnumerable<T> vs. IQueryable<T>

I would like to clarify a few things due to seemingly conflicting responses (mostly surrounding IEnumerable).

(1) IQueryable extends the IEnumerable interface. (You can send an IQueryable to something which expects IEnumerable without error.)

(2) Both IQueryable and IEnumerable LINQ attempt lazy loading when iterating over the result set. (Note that implementation can be seen in interface extension methods for each type.)

In other words, IEnumerables are not exclusively "in-memory". IQueryables are not always executed on the database. IEnumerable must load things into memory (once retrieved, possibly lazily) because it has no abstract data provider. IQueryables rely on an abstract provider (like LINQ-to-SQL), although this could also be the .NET in-memory provider.

Sample use case

(a) Retrieve list of records as IQueryable from EF context. (No records are in-memory.)

(b) Pass the IQueryable to a view whose model is IEnumerable. (Valid. IQueryable extends IEnumerable.)

(c) Iterate over and access the data set's records, child entities and properties from the view. (May cause exceptions!)

Possible Issues

(1) The IEnumerable attempts lazy loading and your data context is expired. Exception thrown because provider is no longer available.

(2) Entity Framework entity proxies are enabled (the default), and you attempt to access a related (virtual) object with an expired data context. Same as (1).

(3) Multiple Active Result Sets (MARS). If you are iterating over the IEnumerable in a foreach( var record in resultSet ) block and simultaneously attempt to access record.childEntity.childProperty, you may end up with MARS due to lazy loading of both the data set and the relational entity. This will cause an exception if it is not enabled in your connection string.

Solution

  • I have found that enabling MARS in the connection string works unreliably. I suggest you avoid MARS unless it is well-understood and explicitly desired.

Execute the query and store results by invoking resultList = resultSet.ToList() This seems to be the most straightforward way of ensuring your entities are in-memory.

In cases where the you are accessing related entities, you may still require a data context. Either that, or you can disable entity proxies and explicitly Include related entities from your DbSet.

How to get data from database in javascript based on the value passed to the function

'SELECT * FROM Employ where number = ' + parseInt(val, 10) + ';'

For example, if val is "10" then this will end up building the string:

"SELECT * FROM Employ where number = 10;"

Lock screen orientation (Android)

In the Manifest, you can set the screenOrientation to landscape. It would look something like this in the XML:

<activity android:name="MyActivity"
android:screenOrientation="landscape"
android:configChanges="keyboardHidden|orientation|screenSize">
...
</activity>

Where MyActivity is the one you want to stay in landscape.

The android:configChanges=... line prevents onResume(), onPause() from being called when the screen is rotated. Without this line, the rotation will stay as you requested but the calls will still be made.

Note: keyboardHidden and orientation are required for < Android 3.2 (API level 13), and all three options are required 3.2 or above, not just orientation.

Which Java library provides base64 encoding/decoding?

Java 9

Use the Java 8 solution. Note DatatypeConverter can still be used, but it is now within the java.xml.bind module which will need to be included.

module org.example.foo {
    requires java.xml.bind;
}

Java 8

Java 8 now provides java.util.Base64 for encoding and decoding base64.

Encoding

byte[] message = "hello world".getBytes(StandardCharsets.UTF_8);
String encoded = Base64.getEncoder().encodeToString(message);
System.out.println(encoded);
// => aGVsbG8gd29ybGQ=

Decoding

byte[] decoded = Base64.getDecoder().decode("aGVsbG8gd29ybGQ=");
System.out.println(new String(decoded, StandardCharsets.UTF_8));
// => hello world

Java 6 and 7

Since Java 6 the lesser known class javax.xml.bind.DatatypeConverter can be used. This is part of the JRE, no extra libraries required.

Encoding

byte[] message = "hello world".getBytes("UTF-8");
String encoded = DatatypeConverter.printBase64Binary(message);
System.out.println(encoded);
// => aGVsbG8gd29ybGQ=  

Decoding

byte[] decoded = DatatypeConverter.parseBase64Binary("aGVsbG8gd29ybGQ=");
System.out.println(new String(decoded, "UTF-8"));
// => hello world

Html: Difference between cell spacing and cell padding

CellSpacing as the name suggests it is the Space between the Adjacent cells and CellPadding on the other hand means the padding around the cell content.

DateTime and CultureInfo

You may try the following:

System.Globalization.CultureInfo cultureinfo =
        new System.Globalization.CultureInfo("nl-NL");
DateTime dt = DateTime.Parse(date, cultureinfo);

Submitting a form on 'Enter' with jQuery?

Return false to prevent the keystroke from continuing.

non static method cannot be referenced from a static context

Violating the Java naming conventions (variable names and method names start with lowercase, class names start with uppercase) is contributing to your confusion.

The variable Random is only "in scope" inside the main method. It's not accessible to any methods called by main. When you return from main, the variable disappears (it's part of the stack frame).

If you want all of the methods of your class to use the same Random instance, declare a member variable:

class MyObj {
  private final Random random = new Random();
  public void compTurn() {
    while (true) {
      int a = random.nextInt(10);
      if (possibles[a] == 1) 
        break;
    }
  }
}

Prevent a webpage from navigating away using JavaScript

The equivalent in a more modern and browser compatible way, using modern addEventListener APIs.

window.addEventListener('beforeunload', (event) => {
  // Cancel the event as stated by the standard.
  event.preventDefault();
  // Chrome requires returnValue to be set.
  event.returnValue = '';
});

Source: https://developer.mozilla.org/en-US/docs/Web/Events/beforeunload

What is the purpose of a plus symbol before a variable?

As explained in other answers it converts the variable to a number. Specially useful when d can be either a number or a string that evaluates to a number.

Example (using the addMonths function in the question):

addMonths(34,1,true);
addMonths("34",1,true);

then the +d will evaluate to a number in all cases. Thus avoiding the need to check for the type and take different code paths depending on whether d is a number, a function or a string that can be converted to a number.

Postgres: check if array field contains value?

This should work:

select * from mytable where 'Journal'=ANY(pub_types);

i.e. the syntax is <value> = ANY ( <array> ). Also notice that string literals in postresql are written with single quotes.

Calling async method synchronously

You can access the Result property of the task, which will cause your thread to block until the result is available:

string code = GenerateCodeAsync().Result;

Note: In some cases, this might lead to a deadlock: Your call to Result blocks the main thread, thereby preventing the remainder of the async code to execute. You have the following options to make sure that this doesn't happen:

This does not mean that you should just mindlessly add .ConfigureAwait(false) after all your async calls! For a detailed analysis on why and when you should use .ConfigureAwait(false), see the following blog post:

Converting Java objects to JSON with Jackson

Note: To make the most voted solution work, attributes in the POJO have to be public or have a public getter/setter:

By default, Jackson 2 will only work with fields that are either public, or have a public getter method – serializing an entity that has all fields private or package private will fail.

Not tested yet, but I believe that this rule also applies for other JSON libs like google Gson.

Angular2 RC6: '<component> is not a known element'

I fixed it with help of Sanket's answer and the comments.

What you couldn't know and was not apparent in the Error Message is: I imported the PlannerComponent as a @NgModule.declaration in my App Module (= RootModule).

The error was fixed by importing the PlannerModule as @NgModule.imports.

Before:

@NgModule({
  declarations: [
    AppComponent,
    PlannerComponent,
    ProfilAreaComponent,
    HeaderAreaComponent,
    NavbarAreaComponent,
    GraphAreaComponent,
    EreignisbarAreaComponent
  ],
  imports: [
    BrowserModule,
    RouterModule.forRoot(routeConfig),
    PlannerModule
  ],
  bootstrap: [AppComponent]
})
export class AppModule {

After:

@NgModule({
  declarations: [
    AppComponent
  ],
  imports: [
    BrowserModule,
    RouterModule.forRoot(routeConfig),
    PlannerModule
  ],
  bootstrap: [AppComponent]
})
export class AppModule {
}

Thanks for your help :)

Force page scroll position to top at page refresh in HTML

You can use location.replace instead of location.reload:

location.replace(location.href);

This way page will reload with scroll on top.

Bootstrap - floating navbar button right

Create a separate ul.nav for just that list item and float that ul right.

jsFiddle

Save internal file in my own internal folder in Android

Save:

public boolean saveFile(Context context, String mytext){
    Log.i("TESTE", "SAVE");
    try {
        FileOutputStream fos = context.openFileOutput("file_name"+".txt",Context.MODE_PRIVATE);
        Writer out = new OutputStreamWriter(fos);
        out.write(mytext);
        out.close();
        return true;
    } catch (IOException e) {
        e.printStackTrace();
        return false;
    }
}

Load:

public String load(Context context){
    Log.i("TESTE", "FILE");
    try {
        FileInputStream fis = context.openFileInput("file_name"+".txt");
        BufferedReader r = new BufferedReader(new InputStreamReader(fis));
        String line= r.readLine();
        r.close();
        return line;
    } catch (IOException e) {
        e.printStackTrace();
        Log.i("TESTE", "FILE - false");
        return null;
    }
}

HTTP GET Request in Node.js Express

If you ever need to send GET request to an IP as well as a Domain (Other answers did not mention you can specify a port variable), you can make use of this function:

function getCode(host, port, path, queryString) {
    console.log("(" + host + ":" + port + path + ")" + "Running httpHelper.getCode()")

    // Construct url and query string
    const requestUrl = url.parse(url.format({
        protocol: 'http',
        hostname: host,
        pathname: path,
        port: port,
        query: queryString
    }));

    console.log("(" + host + path + ")" + "Sending GET request")
    // Send request
    console.log(url.format(requestUrl))
    http.get(url.format(requestUrl), (resp) => {
        let data = '';

        // A chunk of data has been received.
        resp.on('data', (chunk) => {
            console.log("GET chunk: " + chunk);
            data += chunk;
        });

        // The whole response has been received. Print out the result.
        resp.on('end', () => {
            console.log("GET end of response: " + data);
        });

    }).on("error", (err) => {
        console.log("GET Error: " + err);
    });
}

Don't miss requiring modules at the top of your file:

http = require("http");
url = require('url')

Also bare in mind that you may use https module for communicating over secured network. so these two lines would change:

https = require("https");
...
https.get(url.format(requestUrl), (resp) => { ......

Nothing was returned from render. This usually means a return statement is missing. Or, to render nothing, return null

Another way this issue can pop up on your screen is when you give a condition and insert the return inside of it. If the condition is not satisfied, then there is nothing to return. Hence the error.

export default function Component({ yourCondition }) {

    if(yourCondition === "something") {
        return(
            This will throw this error if this condition is false.
        );
    }
}

All that I did was to insert an outer return with null and it worked fine again.

What is the difference between a static and const variable?

const means constant and their values are defined at compile time rather than explicitly change it during run time also, the value of constant cannot be changed during runtime

However static variables are variables that can be initialised and changed at run time. However, static are different from the variables in the sense that static variables retain their values for the whole of the program ie their lifetime is of the program or until the memory is de allocated by the program by using dynamic allocation method. However, even though they retain their values for the whole lifetime of the program they are inaccessible outside the code block they are in

For more info on static variables refer here

installing apache: no VCRUNTIME140.dll

Be sure you have C++ Redistributable for Visual Studio 2015 RC. Try to download the last version:

https://www.microsoft.com/en-us/download/details.aspx?id=52685

Obs: Credit to parsecer

Eliminate space before \begin{itemize}

\renewcommand{\@listI}{%
\leftmargin=25pt
\rightmargin=0pt
\labelsep=5pt
\labelwidth=20pt
\itemindent=0pt
\listparindent=0pt
\topsep=0pt plus 2pt minus 4pt
\partopsep=0pt plus 1pt minus 1pt
\parsep=0pt plus 1pt
\itemsep=\parsep}

jQuery date/time picker

Just to add to the info here, The Fluid Project has a nice wiki write-up overviewing a large number of date and/or time pickers here.

Center Oversized Image in Div

Do not use fixed or an explicit width or height to the image tag. Instead, code it:

      max-width:100%;
      max-height:100%;

ex: http://jsfiddle.net/xwrvxser/1/

Mysql Compare two datetime fields

Do you want to order it?

Select * From temp where mydate > '2009-06-29 04:00:44' ORDER BY mydate;

Failed to execute 'postMessage' on 'DOMWindow': The target origin provided does not match the recipient window's origin ('null')

My issue was I was instatiating the player completely from start but I used an iframe instead of a wrapper div.

How do I rewrite URLs in a proxy response in NGINX

We should first read the documentation on proxy_pass carefully and fully.

The URI passed to upstream server is determined based on whether "proxy_pass" directive is used with URI or not. Trailing slash in proxy_pass directive means that URI is present and equal to /. Absense of trailing slash means hat URI is absent.

Proxy_pass with URI:

location /some_dir/ {
    proxy_pass http://some_server/;
}

With the above, there's the following proxy:

http:// your_server/some_dir/ some_subdir/some_file ->
http:// some_server/          some_subdir/some_file

Basically, /some_dir/ gets replaced by / to change the request path from /some_dir/some_subdir/some_file to /some_subdir/some_file.

Proxy_pass without URI:

location /some_dir/ {
    proxy_pass http://some_server;
}

With the second (no trailing slash): the proxy goes like this:

http:// your_server /some_dir/some_subdir/some_file ->
http:// some_server /some_dir/some_subdir/some_file

Basically, the full original request path gets passed on without changes.


So, in your case, it seems you should just drop the trailing slash to get what you want.


Caveat

Note that automatic rewrite only works if you don't use variables in proxy_pass. If you use variables, you should do rewrite yourself:

location /some_dir/ {
  rewrite    /some_dir/(.*) /$1 break;
  proxy_pass $upstream_server;
}

There are other cases where rewrite wouldn't work, that's why reading documentation is a must.


Edit

Reading your question again, it seems I may have missed that you just want to edit the html output.

For that, you can use the sub_filter directive. Something like ...

location /admin/ {
    proxy_pass http://localhost:8080/;
    sub_filter "http://your_server/" "http://your_server/admin/";
    sub_filter_once off;
}

Basically, the string you want to replace and the replacement string

Freezing Row 1 and Column A at the same time

Select cell B2 and click "Freeze Panes" this will freeze Row 1 and Column A.

For future reference, selecting Freeze Panes in Excel will freeze the rows above your selected cell and the columns to the left of your selected cell. For example, to freeze rows 1 and 2 and column A, you could select cell B3 and click Freeze Panes. You could also freeze columns A and B and row 1, by selecting cell C2 and clicking "Freeze Panes".

Visual Aid on Freeze Panes in Excel 2010 - http://www.dummies.com/how-to/content/how-to-freeze-panes-in-an-excel-2010-worksheet.html

Microsoft Reference Guide (More Complicated, but resourceful none the less) - http://office.microsoft.com/en-us/excel-help/freeze-or-lock-rows-and-columns-HP010342542.aspx

How do I use StringUtils in Java?

If you're developing for Android there is TextUtils class which may help you:

import android.text.TextUtils;

It is really helps a lot to check equality of Strings.
For example if you need to check Strings s1, s2 equality (which may be nulls) you may use instead of

if( (s1 != null && !s1.equals(s2)) || (s1 == null && s2 != null) ) 
{ ... }

this simple method:

if( !TextUtils.equals(s1, s2) )
{ ... }

As for initial question - for replacement it's easier to use s1.replace().

Regex Named Groups in Java

For people coming to this late: Java 7 adds named groups. Matcher.group(String groupName) documentation.

joining two select statements

Not sure what you are trying to do, but you have two select clauses. Do this instead:

SELECT * 
FROM ( SELECT * 
       FROM orders_products 
       INNER JOIN orders ON orders_products.orders_id = orders.orders_id 
       WHERE products_id = 181) AS A
JOIN ( SELECT * 
       FROM orders_products 
       INNER JOIN orders ON orders_products.orders_id = orders.orders_id
       WHERE products_id = 180) AS B

ON A.orders_id=B.orders_id

Update:

You could probably reduce it to something like this:

SELECT o.orders_id, 
       op1.products_id, 
       op1.quantity, 
       op2.products_id, 
       op2.quantity
FROM orders o
INNER JOIN orders_products op1 on o.orders_id = op1.orders_id  
INNER JOIN orders_products op2 on o.orders_id = op2.orders_id  
WHERE op1.products_id = 180
AND op2.products_id = 181

How does HTTP_USER_AGENT work?

http://www.useragentstring.com/

Visit that page, it'll give you a good explanation of each element of your user agent.

Mozilla:

MozillaProductSlice. Claims to be a Mozilla based user agent, which is only true for Gecko browsers like Firefox and Netscape. For all other user agents it means 'Mozilla-compatible'. In modern browsers, this is only used for historical reasons. It has no real meaning anymore

How to remove package using Angular CLI?

I think best approach until Angular team add this feature to cli is first create angular (ng new something) in other place and then add what you want to delete. Using git to check witch files are changed or added by angular cli. then you can revert that changes. Be careful of untracked files from .gitignore.

ORA-01034: ORACLE not available ORA-27101: shared memory realm does not exist

I faced the same issue while creating the connection on SQLDeveloper "ORA-01034: ORACLE not available ORA-27101: shared memory realm does not exist"

Solution:

1.Update the listene.ora file to include the SID.

  SID_LIST_LISTENER =
    (SID_LIST =
      (SID_DESC =
        (SID_NAME = PLSExtProc)
        (ORACLE_HOME = C:\oraclexe\app\oracle\product\11.2.0\server)
        (PROGRAM = extproc)
      )
      (SID_DESC =
        (SID_NAME = CLRExtProc)
        (ORACLE_HOME = C:\oraclexe\app\oracle\product\11.2.0\server)
        (PROGRAM = extproc)
      )
      (SID_DESC =
        ((GLOBAL_DBNAME = XE.DB)
        ((ORACLE_HOME = C:\oraclexe\app\oracle\product\11.2.0\server)
        ((SID_NAME = XE)
      )
    )

  LISTENER =
    (DESCRIPTION_LIST =
      (DESCRIPTION =
        (ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC1))
        (ADDRESS = (PROTOCOL = TCP)(HOST = USMUMTBALAKDAS2.us.deloitte.com)(PORT = 1521))
      )
    )

  DEFAULT_SERVICE_LISTENER = (XE)

The Oraclexe directory may have the permission set to "ReadOnly", Change the directory/sub-directory permission to read/write and restart the listener services. Problem is solved.

PostgreSQL how to see which queries have run

Turn on the server log:

log_statement = all

This will log every call to the database server.

I would not use log_statement = all on a production server. Produces huge log files.
The manual about logging-parameters:

log_statement (enum)

Controls which SQL statements are logged. Valid values are none (off), ddl, mod, and all (all statements). [...]

Resetting the log_statement parameter requires a server reload (SIGHUP). A restart is not necessary. Read the manual on how to set parameters.

Don't confuse the server log with pgAdmin's log. Two different things!

You can also look at the server log files in pgAdmin, if you have access to the files (may not be the case with a remote server) and set it up correctly. In pgadmin III, have a look at: Tools -> Server status. That option was removed in pgadmin4.

I prefer to read the server log files with vim (or any editor / reader of your choice).

Iterate Multi-Dimensional Array with Nested Foreach Statement

int[,] arr =  { 
                {1, 2, 3},
                {4, 5, 6},
                {7, 8, 9}
              };
 for(int i = 0; i < arr.GetLength(0); i++){
      for (int j = 0; j < arr.GetLength(1); j++)
           Console.Write( "{0}\t",arr[i, j]);
      Console.WriteLine();
    }

output:  1  2  3
         4  5  6
         7  8  9

Debugging in Maven?

Why not use the JPDA and attach to the launched process from a separate debugger process ? You should be able to specify the appropriate options in Maven to launch your process with the debugging hooks enabled. This article has more information.

Playing a MP3 file in a WinForm application

  1. first go to the properties of your project
  2. click on add references
  3. add the library under COM object for window media player then type your code where you want


    Source:

        WMPLib.WindowsMediaPlayer wplayer = new WMPLib.WindowsMediaPlayer();
    
        wplayer.URL = @"C:\Users\Adil M\Documents\Visual Studio 2012\adil.mp3";
        wplayer.controls.play();
    

The client and server cannot communicate, because they do not possess a common algorithm - ASP.NET C# IIS TLS 1.0 / 1.1 / 1.2 - Win32Exception

In previous answers a few registry keys that might not exist are missed. They are SchUseStrongCrypto that must exist to allow to TLS protocols work properly.

After the registry keys have been imported to registry it should not be required to make changes in code like

ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls;

Below there are all registry keys and values that are needed for x64 windows OS. If you have 32bit OS (x86) just remove the last 2 lines. TLS 1.0 will be disabled by the registry script. Restarting OS is required.

Windows Registry Editor Version 5.00

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols]

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\SSL 2.0]

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\SSL 2.0\Client]
"DisabledByDefault"=dword:00000001
"enabled"=dword:00000000

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\SSL 2.0\server]
"disabledbydefault"=dword:00000001
"enabled"=dword:00000000

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\ssl 3.0]

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\ssl 3.0\client]
"disabledbydefault"=dword:00000001
"enabled"=dword:00000000

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\ssl 3.0\server]
"disabledbydefault"=dword:00000001
"enabled"=dword:00000000

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\tls 1.0]

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\tls 1.0\client]
"disabledbydefault"=dword:00000001
"enabled"=dword:00000000

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\tls 1.0\server]
"disabledbydefault"=dword:00000001
"enabled"=dword:00000000

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\tls 1.1]

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\tls 1.1\client]
"disabledbydefault"=dword:00000000
"enabled"=dword:00000001

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\tls 1.1\server]
"disabledbydefault"=dword:00000000
"enabled"=dword:00000001

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\tls 1.2]

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\tls 1.2\client]
"disabledbydefault"=dword:00000000
"enabled"=dword:00000001

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\tls 1.2\server]
"disabledbydefault"=dword:00000000
"enabled"=dword:00000001

[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\.NETFramework\v4.0.30319]
"SchUseStrongCrypto"=dword:00000001

[HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Microsoft\.NETFramework\v4.0.30319]
"SchUseStrongCrypto"=dword:00000001

Can't bind to 'routerLink' since it isn't a known property

In the current component's module import RouterModule.

Like:-

import {RouterModule} from '@angular/router';
@NgModule({
   declarations:[YourComponents],
   imports:[RouterModule]

...

It helped me.

Bootstrap trying to load map file. How to disable it? Do I need to do it?

Delete /*# sourceMappingURL=bootstrap.min.css.map */ in css/bootstrap.min.css

and delete /*# sourceMappingURL=bootstrap.css.map */ in css/bootstrap.css

How do I detect what .NET Framework versions and service packs are installed?

Enumerate the subkeys of HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\NET Framework Setup\NDP. Each subkey is a .NET version. It should have Install=1 value if it's present on the machine, an SP value that shows the service pack and an MSI=1 value if it was installed using an MSI. (.NET 2.0 on Windows Vista doesn't have the last one for example, as it is part of the OS.)

how to set textbox value in jquery

I think you want to set the response of the call to the URL 'compz.php?prodid=' + x + '&qbuys=' + y as value of the textbox right? If so, you have to do something like:

$.get('compz.php?prodid=' + x + '&qbuys=' + y, function(data) {
    $('#subtotal').val(data);
});

Reference: get()

You have two errors in your code:

  • load() puts the HTML returned from the Ajax into the specified element:

    Load data from the server and place the returned HTML into the matched element.

    You cannot set the value of a textbox with that method.

  • $(selector).load() returns the a jQuery object. By default an object is converted to [object Object] when treated as string.

Further clarification:

Assuming your URL returns 5.

If your HTML looks like:

<div id="foo"></div>

then the result of

$('#foo').load('/your/url');

will be

<div id="foo">5</div>

But in your code, you have an input element. Theoretically (it is not valid HTML and does not work as you noticed), an equivalent call would result in

<input id="foo">5</input>

But you actually need

<input id="foo" value="5" />

Therefore, you cannot use load(). You have to use another method, get the response and set it as value yourself.

Using '<%# Eval("item") %>'; Handling Null Value and showing 0 against

Use IIF.

<asp:Label ID="Label18" Text='<%# IIF(Eval("item") Is DBNull.Value,"0", Eval("item") %>' 
runat="server"></asp:Label>

Scale Image to fill ImageView width and keep aspect ratio

Use these properties in ImageView to keep aspect ratio:

android:adjustViewBounds="true"
android:scaleType="fitXY"

Storing files in SQL Server

You might read up on FILESTREAM. Here is some info from the docs that should help you decide:

If the following conditions are true, you should consider using FILESTREAM:

  • Objects that are being stored are, on average, larger than 1 MB.
  • Fast read access is important.
  • You are developing applications that use a middle tier for application logic.

For smaller objects, storing varbinary(max) BLOBs in the database often provides better streaming performance.

Is there a way to specify which pytest tests to run from a file?

Method 1: Randomly selected tests. Long and ugly.

python -m pytest test/stress/test_performance.py::TestPerformance::test_continuous_trigger test/integration/test_config.py::TestConfig::test_valid_config

Method 2: Use Keyword Expressions.

Note: I am searching by testcase names. Same is applicable to TestClass names.

Case 1: The below will run whichever is found. Since we have used 'OR' .

python -m pytest -k 'test_password_valid or test_no_configuration'

Lets say the two above are actually correct, 2 tests will be run.

Case 2: Now an incorrect name and another correct name.

python -m pytest -k 'test_password_validzzzzzz or test_no_configuration' 

Only one is found and run.

Case 3: If you want all tests to run or no one, then use AND

python -m pytest -k 'test_password_valid and test_no_configuration'

Both will be run if correct or none.

Case 4: Run test only in one folder:

python -m pytest test/project1/integration -k 'test_password_valid or test_no_configuration'

Case 5: Run test from only one file.

python -m pytest test/integration/test_authentication.py -k 'test_password_expiry or test_incorrect_password'

Case 6: Run all tests except the match.

python -m pytest test/integration/test_authentication.py -k 'not  test_incorrect_password'

Python - How to convert JSON File to Dataframe

jsondata = '{"0001":{"FirstName":"John","LastName":"Mark","MiddleName":"Lewis","username":"johnlewis2","password":"2910"}}'
import json
import pandas as pd
jdata = json.loads(jsondata)
df = pd.DataFrame(jdata)
print df.T

This should look like this:.

         FirstName LastName MiddleName password    username
0001      John     Mark      Lewis     2910  johnlewis2

How do you create a temporary table in an Oracle database?

CREATE GLOBAL TEMPORARY TABLE Table_name
    (startdate DATE,
     enddate DATE,
     class CHAR(20))
  ON COMMIT DELETE ROWS;

Git and nasty "error: cannot lock existing info/refs fatal"

I fixed this by doing the following

git branch --unset-upstream
rm .git/refs/remotes/origin/{branch}
git gc --prune=now
git branch --set-upstream-to=origin/{branch} {branch}
#or git push --set-upstream origin {branch}
git pull

This assuming that your local and remote branches are aligned and you are just getting the refs error as non fatal.

Node.js request CERT_HAS_EXPIRED

I had this problem on production with Heroku and locally while debugging on my macbook pro this morning.

After an hour of debugging, this resolved on its own both locally and on production. I'm not sure what fixed it, so that's a bit annoying. It happened right when I thought I did something, but reverting my supposed fix didn't bring the problem back :(

Interestingly enough, it appears my database service, MongoDb has been having server problems since this morning, so there's a good chance this was related to it.

enter image description here

TypeScript sorting an array

Numbers

When sorting numbers, you can use the compact comparison:

var numericArray: number[] = [2, 3, 4, 1, 5, 8, 11];

var sortedArray: number[] = numericArray.sort((n1,n2) => n1 - n2);

i.e. - rather than <.

Other Types

If you are comparing anything else, you'll need to convert the comparison into a number.

var stringArray: string[] = ['AB', 'Z', 'A', 'AC'];

var sortedArray: string[] = stringArray.sort((n1,n2) => {
    if (n1 > n2) {
        return 1;
    }

    if (n1 < n2) {
        return -1;
    }

    return 0;
});

Objects

For objects, you can sort based on a property, bear in mind the above information about being able to short-hand number types. The below example works irrespective of the type.

var objectArray: { age: number; }[] = [{ age: 10}, { age: 1 }, {age: 5}];

var sortedArray: { age: number; }[] = objectArray.sort((n1,n2) => {
    if (n1.age > n2.age) {
        return 1;
    }

    if (n1.age < n2.age) {
        return -1;
    }

    return 0;
});

Responsive css background images

Try this :

background-image: url(_images/bg.png);
background-repeat: no-repeat;
background-position: center center;
background-attachment: fixed;
background-size: cover;

How to generate a QR Code for an Android application?

zxing does not (only) provide a web API; really, that is Google providing the API, from source code that was later open-sourced in the project.

As Rob says here you can use the Java source code for the QR code encoder to create a raw barcode and then render it as a Bitmap.

I can offer an easier way still. You can call Barcode Scanner by Intent to encode a barcode. You need just a few lines of code, and two classes from the project, under android-integration. The main one is IntentIntegrator. Just call shareText().

Using set_facts and with_items together in Ansible

Updated 2018-06-08: My previous answer was a bit of hack so I have come back and looked at this again. This is a cleaner Jinja2 approach.

- name: Set fact 4
  set_fact:
    foo: "{% for i in foo_result.results %}{% do foo.append(i) %}{% endfor %}{{ foo }}"

I am adding this answer as current best answer for Ansible 2.2+ does not completely cover the original question. Thanks to Russ Huguley for your answer this got me headed in the right direction but it left me with a concatenated string not a list. This solution gets a list but becomes even more hacky. I hope this gets resolved in a cleaner manner.

- name: build foo_string
  set_fact:
    foo_string: "{% for i in foo_result.results %}{{ i.ansible_facts.foo_item }}{% if not loop.last %},{% endif %}{%endfor%}"

- name: set fact foo
  set_fact:
    foo: "{{ foo_string.split(',') }}"

Use of Java's Collections.singletonList()?

To answer your immutable question:

Collections.singletonList will create an immutable List. An immutable List (also referred to as an unmodifiable List) cannot have it's contents changed. The methods to add or remove items will throw exceptions if you try to alter the contents.

A singleton List contains only that item and cannot be altered.

SQL query question: SELECT ... NOT IN

SELECT Reservations.idCustomer FROM Reservations (nolock)
LEFT OUTER JOIN @reservations ExcludedReservations (nolock) ON Reservations.idCustomer=ExcludedReservations.idCustomer AND DATEPART(hour, ExcludedReservations.insertDate) < 2
WHERE ExcludedReservations.idCustomer IS NULL AND Reservations.idCustomer IS NOT NULL
GROUP BY Reservations.idCustomer

[Update: Added additional criteria to handle idCustomer being NULL, which was apparently the main issue the original poster had]

How to schedule a stored procedure in MySQL

If you're open to out-of-the-DB solution: You could set up a cron job that runs a script that will itself call the procedure.

Which data type for latitude and longitude?

I strongly advocate for PostGis. It's specific for that kind of datatype and it has out of the box methods to calculate distance between points, among other GIS operations that you can find useful in the future

How do I get rid of an element's offset using CSS?

You can apply a reset css to get rid of those 'defaults'. Here is an example of a reset css http://meyerweb.com/eric/tools/css/reset/ . Just apply the reset styles BEFORE your own styles.

Extract a single (unsigned) integer from a string

For floating numbers,

preg_match_all('!\d+\.?\d+!', $string ,$match);

Thanks for pointing out the mistake. @mickmackusa

Bootstrap button drop-down inside responsive table not visible because of scroll

Inside bootstrap.css search the next code:

.fixed-table-body {
  overflow-x: auto;
  overflow-y: auto;
  height: 100%;
}

...and update with this:

.fixed-table-body {
  overflow-x: visible;
  overflow-y: visible;
  height: 100%;
}

Call an overridden method from super class in typescript

If you want a super class to call a function from a subclass, the cleanest way is to define an abstract pattern, in this manner you explicitly know the method exists somewhere and must be overridden by a subclass.

This is as an example, normally you do not call a sub method within the constructor as the sub instance is not initialized yet… (reason why you have an "undefined" in your question's example)

abstract class A {
    // The abstract method the subclass will have to call
    protected abstract doStuff():void;

    constructor(){
     alert("Super class A constructed, calling now 'doStuff'")
     this.doStuff();
    }
}

class B extends A{

    // Define here the abstract method
    protected doStuff()
    {
        alert("Submethod called");
    }
}

var b = new B();

Test it Here

And if like @Max you really want to avoid implementing the abstract method everywhere, just get rid of it. I don't recommend this approach because you might forget you are overriding the method.

abstract class A {
    constructor() {
        alert("Super class A constructed, calling now 'doStuff'")
        this.doStuff();
    }

    // The fallback method the subclass will call if not overridden
    protected doStuff(): void {
        alert("Default doStuff");
    };
}

class B extends A {
    // Override doStuff()
    protected doStuff() {
        alert("Submethod called");
    }
}

class C extends A {
    // No doStuff() overriding, fallback on A.doStuff()
}

var b = new B();
var c = new C();

Try it Here

Laravel Update Query

You could use the Laravel query builder, but this is not the best way to do it.

Check Wader's answer below for the Eloquent way - which is better as it allows you to check that there is actually a user that matches the email address, and handle the error if there isn't.

DB::table('users')
        ->where('email', $userEmail)  // find your user by their email
        ->limit(1)  // optional - to ensure only one record is updated.
        ->update(array('member_type' => $plan));  // update the record in the DB. 

If you have multiple fields to update you can simply add more values to that array at the end.

How to change the order of DataFrame columns?

Here is a very simple answer to this(only one line).

You can do that after you added the 'n' column into your df as follows.

import numpy as np
import pandas as pd

df = pd.DataFrame(np.random.rand(10, 5))
df['mean'] = df.mean(1)
df
           0           1           2           3           4        mean
0   0.929616    0.316376    0.183919    0.204560    0.567725    0.440439
1   0.595545    0.964515    0.653177    0.748907    0.653570    0.723143
2   0.747715    0.961307    0.008388    0.106444    0.298704    0.424512
3   0.656411    0.809813    0.872176    0.964648    0.723685    0.805347
4   0.642475    0.717454    0.467599    0.325585    0.439645    0.518551
5   0.729689    0.994015    0.676874    0.790823    0.170914    0.672463
6   0.026849    0.800370    0.903723    0.024676    0.491747    0.449473
7   0.526255    0.596366    0.051958    0.895090    0.728266    0.559587
8   0.818350    0.500223    0.810189    0.095969    0.218950    0.488736
9   0.258719    0.468106    0.459373    0.709510    0.178053    0.414752


### here you can add below line and it should work 
# Don't forget the two (()) 'brackets' around columns names.Otherwise, it'll give you an error.

df = df[list(('mean',0, 1, 2,3,4))]
df

        mean           0           1           2           3           4
0   0.440439    0.929616    0.316376    0.183919    0.204560    0.567725
1   0.723143    0.595545    0.964515    0.653177    0.748907    0.653570
2   0.424512    0.747715    0.961307    0.008388    0.106444    0.298704
3   0.805347    0.656411    0.809813    0.872176    0.964648    0.723685
4   0.518551    0.642475    0.717454    0.467599    0.325585    0.439645
5   0.672463    0.729689    0.994015    0.676874    0.790823    0.170914
6   0.449473    0.026849    0.800370    0.903723    0.024676    0.491747
7   0.559587    0.526255    0.596366    0.051958    0.895090    0.728266
8   0.488736    0.818350    0.500223    0.810189    0.095969    0.218950
9   0.414752    0.258719    0.468106    0.459373    0.709510    0.178053

How to check if X server is running?

You can use xdpyinfo (can be installed via apt-get install x11-utils).

COUNT / GROUP BY with active record?

$this->db->select('overal_points');
$this->db->where('point_publish', 1);
$this->db->order_by('overal_points', 'desc'); 
$query = $this->db->get('company', 4)->result();

Easily measure elapsed time

The reason both values are the same is because your long procedure doesn't take that long - less than one second. You can try just adding a long loop (for (int i = 0; i < 100000000; i++) ; ) at the end of the function to make sure this is the issue, then we can go from there...

In case the above turns out to be true, you will need to find a different system function (I understand you work on linux, so I can't help you with the function name) to measure time more accurately. I am sure there is a function simular to GetTickCount() in linux, you just need to find it.

Editing hosts file to redirect url?

You could use the RedirectMatch directive in Apache to do something similar you want.

It's pretty simple.

RedirectMatch / http://222.222.222.222/

Anyway, I can't see any reason to do that thing. Aren't you trying to intercept traffic? There are better ways. For Linux boxes as a router: iptables -j REDIRECT + Squid or Apache. For Cisco routers, you can use WCCP to a Cache or Web Server...

How to send a "multipart/form-data" with requests in python?

Basically, if you specify a files parameter (a dictionary), then requests will send a multipart/form-data POST instead of a application/x-www-form-urlencoded POST. You are not limited to using actual files in that dictionary, however:

>>> import requests
>>> response = requests.post('http://httpbin.org/post', files=dict(foo='bar'))
>>> response.status_code
200

and httpbin.org lets you know what headers you posted with; in response.json() we have:

>>> from pprint import pprint
>>> pprint(response.json()['headers'])
{'Accept': '*/*',
 'Accept-Encoding': 'gzip, deflate',
 'Connection': 'close',
 'Content-Length': '141',
 'Content-Type': 'multipart/form-data; '
                 'boundary=c7cbfdd911b4e720f1dd8f479c50bc7f',
 'Host': 'httpbin.org',
 'User-Agent': 'python-requests/2.21.0'}

Better still, you can further control the filename, content type and additional headers for each part by using a tuple instead of a single string or bytes object. The tuple is expected to contain between 2 and 4 elements; the filename, the content, optionally a content type, and an optional dictionary of further headers.

I'd use the tuple form with None as the filename, so that the filename="..." parameter is dropped from the request for those parts:

>>> files = {'foo': 'bar'}
>>> print(requests.Request('POST', 'http://httpbin.org/post', files=files).prepare().body.decode('utf8'))
--bb3f05a247b43eede27a124ef8b968c5
Content-Disposition: form-data; name="foo"; filename="foo"

bar
--bb3f05a247b43eede27a124ef8b968c5--
>>> files = {'foo': (None, 'bar')}
>>> print(requests.Request('POST', 'http://httpbin.org/post', files=files).prepare().body.decode('utf8'))
--d5ca8c90a869c5ae31f70fa3ddb23c76
Content-Disposition: form-data; name="foo"

bar
--d5ca8c90a869c5ae31f70fa3ddb23c76--

files can also be a list of two-value tuples, if you need ordering and/or multiple fields with the same name:

requests.post(
    'http://requestb.in/xucj9exu',
    files=(
        ('foo', (None, 'bar')),
        ('foo', (None, 'baz')),
        ('spam', (None, 'eggs')),
    )
)

If you specify both files and data, then it depends on the value of data what will be used to create the POST body. If data is a string, only it willl be used; otherwise both data and files are used, with the elements in data listed first.

There is also the excellent requests-toolbelt project, which includes advanced Multipart support. It takes field definitions in the same format as the files parameter, but unlike requests, it defaults to not setting a filename parameter. In addition, it can stream the request from open file objects, where requests will first construct the request body in memory:

from requests_toolbelt.multipart.encoder import MultipartEncoder

mp_encoder = MultipartEncoder(
    fields={
        'foo': 'bar',
        # plain file object, no filename or mime type produces a
        # Content-Disposition header with just the part name
        'spam': ('spam.txt', open('spam.txt', 'rb'), 'text/plain'),
    }
)
r = requests.post(
    'http://httpbin.org/post',
    data=mp_encoder,  # The MultipartEncoder is posted as data, don't use files=...!
    # The MultipartEncoder provides the content-type header with the boundary:
    headers={'Content-Type': mp_encoder.content_type}
)

Fields follow the same conventions; use a tuple with between 2 and 4 elements to add a filename, part mime-type or extra headers. Unlike the files parameter, no attempt is made to find a default filename value if you don't use a tuple.

How to add a line break in an Android TextView?

As I know in the previous version of android studio uses separate lines " \n " code. But new one (4.1.2) uses "<br/" to separate lines. For example - Old one:

<string name="string_name">Sample text 1 \n Sample text 2 </string>

New one:

<string name="string_name">Sample text 1 <br/> Sample text 2 </string>

Get current date in Swift 3?

You say in a comment you want to get "15.09.2016".

For this, use Date and DateFormatter:

let date = Date()
let formatter = DateFormatter()

Give the format you want to the formatter:

formatter.dateFormat = "dd.MM.yyyy"

Get the result string:

let result = formatter.string(from: date)

Set your label:

label.text = result

Result:

15.09.2016

Find position of a node using xpath

The problem is that the position of the node doesn't mean much without a context.

The following code will give you the location of the node in its parent child nodes

using System;
using System.Xml;

public class XpathFinder
{
    public static void Main(string[] args)
    {
        XmlDocument xmldoc = new XmlDocument();
        xmldoc.Load(args[0]);
        foreach ( XmlNode xn in xmldoc.SelectNodes(args[1]) )
        {
            for (int i = 0; i < xn.ParentNode.ChildNodes.Count; i++)
            {
                if ( xn.ParentNode.ChildNodes[i].Equals( xn ) )
                {
                    Console.Out.WriteLine( i );
                    break;
                }
            }
        }
    }
}

What values for checked and selected are false?

The checked and selected attributes are allowed only two values, which are a copy of the attribute name and (from HTML 5 onwards) an empty string. Giving any other value is an error.

If you don't want to set the attribute, then the entire attribute must be omitted.

Note that in HTML 4 you may omit everything except the value. HTML 5 changed this to omit everything except the name (which makes no practical difference).

Thus, the complete (aside from variations in cAsE) set of valid representations of the attribute are:

<input ... checked="checked"> <!-- All versions of HTML / XHTML -->
<input ...          checked > <!-- Only HTML 4.01 and earlier -->
<input ... checked          > <!-- Only HTML 5 and later -->
<input ... checked=""       > <!-- Only HTML 5 and later -->

Documents served as text/html (HTML or XHTML) will be fed through a tag soup parser, and the presence of a checked attribute (with any value) will be treated as "This element should be checked". Thus, while invalid, checked="true", checked="yes", and checked="false" will all trigger the checked state.

I've not had any inclination to find out what error recovery mechanisms are in place for XML parsing mode should a different value be given to the attribute, but I would expect that the legacy of HTML and/or simple error recovery would treat it in the same way: If the attribute is there then the element is checked.

(And all the above applies equally to selected as it does to checked.)

What are advantages of Artificial Neural Networks over Support Vector Machines?

One thing to note is that the two are actually very related. Linear SVMs are equivalent to single-layer NN's (i.e., perceptrons), and multi-layer NNs can be expressed in terms of SVMs. See here for some details.

What is a tracking branch?

tracking branch is nothing but a way to save us some typing.

If we track a branch, we do not have to always type git push origin <branch-name> or git pull origin <branch-name> or git fetch origin <branch-name> or git merge origin <branch-name>. given we named our remote origin, we can just use git push, git pull, git fetch,git merge, respectively.

We track a branch when we:

  1. clone a repository using git clone
  2. When we use git push -u origin <branch-name>. This -u make it a tracking branch.
  3. When we use git branch -u origin/branch_name branch_name

Use string contains function in oracle SQL query

The answer of ADTC works fine, but I've find another solution, so I post it here if someone wants something different.

I think ADTC's solution is better, but mine's also works.

Here is the other solution I found

select p.name
from   person p
where  instr(p.name,chr(8211)) > 0; --contains the character chr(8211) 
                                    --at least 1 time

Thank you.

Get the last inserted row ID (with SQL statement)

Assuming a simple table:

CREATE TABLE dbo.foo(ID INT IDENTITY(1,1), name SYSNAME);

We can capture IDENTITY values in a table variable for further consumption.

DECLARE @IDs TABLE(ID INT);

-- minor change to INSERT statement; add an OUTPUT clause:
INSERT dbo.foo(name) 
  OUTPUT inserted.ID INTO @IDs(ID)
SELECT N'Fred'
UNION ALL
SELECT N'Bob';

SELECT ID FROM @IDs;

The nice thing about this method is (a) it handles multi-row inserts (SCOPE_IDENTITY() only returns the last value) and (b) it avoids this parallelism bug, which can lead to wrong results, but so far is only fixed in SQL Server 2008 R2 SP1 CU5.

Redirect form to different URL based on select option element

This can be archived by adding code on the onchange event of the select control.

For Example:

<select onchange="this.options[this.selectedIndex].value && (window.location = this.options[this.selectedIndex].value);">
    <option value="http://gmail.com">Gmail</option>
    <option value="http://youtube.com">Youtube</option>
</select>

How to set JAVA_HOME in Linux for all users

All operational steps(finding java, parent dir, editing file,...) one solution

zFileProfile="/etc/profile"
zJavaHomePath=$(readlink -ze $(which java) | xargs -0 dirname | xargs -0 dirname)
echo $zJavaHomePath

echo "export JAVA_HOME=\"${zJavaHomePath}\"" >> $zFileProfile
echo "export PATH=\$PATH:\$JAVA_HOME/bin" >> $zFileProfile

Result:

# tail -2 $zFileProfile
export JAVA_HOME="/usr/lib/jvm/java-11-openjdk-11.0.7.10-1.el8_1.x86_64"
export PATH=$PATH:$JAVA_HOME/bin

Explanation:

1) Let's break the full command into pieces

$(readlink -ze $(which java) | xargs -0 dirname | xargs -0 dirname)

2) Find java path from java command

# $(which java)
"/usr/bin/java"

3) Get relative path from symbolic path

# readlink -ze /usr/bin/java
"/usr/lib/jvm/java-11-openjdk-11.0.7.10-1.el8_1.x86_64/bin/java"

4) Get parent path of /usr/lib/jvm/java-11-openjdk-11.0.7.10-1.el8_1.x86_64/bin/java

# readlink -ze /usr/bin/java | xargs -0 dirname
"/usr/lib/jvm/java-11-openjdk-11.0.7.10-1.el8_1.x86_64/bin"

5) Get parent path of /usr/lib/jvm/java-11-openjdk-11.0.7.10-1.el8_1.x86_64/bin/

# readlink -ze /usr/bin/java | xargs -0 dirname | xargs -0 dirname
"/usr/lib/jvm/java-11-openjdk-11.0.7.10-1.el8_1.x86_64"

How can I use PHP to dynamically publish an ical file to be read by Google Calendar?

http://www.kanzaki.com/docs/ical/ has a slightly more readable version of the older spec. It helps as a starting point - many things are still the same.

Also on my site, I have

  1. Some lists of useful resources (see sidebar bottom right) on
    • ical Spec RFC 5545
    • ical Testing Resources
  2. Some notes recorded on my journey working with .ics over the last few years. In particular, you may find this repeating events 'cheatsheet' to be useful.

.ics areas that need careful handling:

  • 'all day' events
  • types of dates (timezone, UTC, or local 'floating') - nb to understand distinction
  • interoperability of recurrence rules