Programs & Examples On #Metadata

Meta-data provides information about one or more aspects of the data. Meta-data may refer to either structural metadata (data about the containers of data) or descriptive metadata (data about data content).

Accessing MP3 metadata with Python

After some initial research I thought songdetails might fit my use case, but it doesn't handle .m4b files. Mutagen does. Note that while some have (reasonably) taken issue with Mutagen's surfacing of format-native keys, that vary from format to format (TIT2 for mp3, title for ogg, \xa9nam for mp4, Title for WMA etc.), mutagen.File() has a (new?) easy=True parameter that provides EasyMP3/EasyID3 tags, which have a consistent, albeit limited, set of keys. I've only done limited testing so far, but the common keys, like album, artist, albumartist, genre, tracknumber, discnumber, etc. are all present and identical for .mb4 and .mp3 files when using easy=True, making it very convenient for my purposes.

VS 2017 Metadata file '.dll could not be found

Another thing that you should check is the Target Framework of any referenced projects to make sure that the calling project is using the same or later version of the framework.

I had this issue, I tried all of the previously suggested answers and then on a hunch checked the frameworks. One of projects being referenced was targeting 4.6.1 when the calling project was only 4.5.2.

How to query the permissions on an Oracle directory?

With Oracle 11g R2 (at least with 11.2.02) there is a view named datapump_dir_objs.

SELECT * FROM datapump_dir_objs;

The view shows the NAME of the directory object, the PATH as well as READ and WRITE permissions for the currently connected user. It does not show any directory objects which the current user has no permission to read from or write to, though.

SQL Server: Extract Table Meta-Data (description, fields and their data types)

Generic information about tables and columns can be found in these tables:

select * from INFORMATION_SCHEMA.TABLES
select * from INFORMATION_SCHEMA.COLUMNS

The table description is an extended property, you can query them from sys.extended_properties:

select 
    TableName = tbl.table_schema + '.' + tbl.table_name, 
    TableDescription = prop.value,
    ColumnName = col.column_name, 
    ColumnDataType = col.data_type
FROM information_schema.tables tbl
INNER JOIN information_schema.columns col 
    ON col.table_name = tbl.table_name
    AND col.table_schema = tbl.table_schema
LEFT JOIN sys.extended_properties prop 
    ON prop.major_id = object_id(tbl.table_schema + '.' + tbl.table_name) 
    AND prop.minor_id = 0
    AND prop.name = 'MS_Description' 
WHERE tbl.table_type = 'base table'

How do I list all tables in all databases in SQL Server in a single result set?

I realize this is a very old thread, but it was very helpful when I had to put together some system documentation for several different servers that were hosting different versions of Sql Server. I ended up creating 4 stored procedures which I am posting here for the benefit of the community. We use Dynamics NAV so the two stored procedures with NAV in the name split the Nav company out of the table name. Enjoy...

1 of 4 - ListServerDatabases

USE [YourDatabase]
GO

/****** Object:  StoredProcedure [pssi].[ListServerDatabases]    Script Date: 10/3/2017 8:56:45 AM ******/
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO

ALTER PROC [dbo].[ListServerDatabases]
(
    @SearchDatabases varchar(max) = NULL,  
    @ExcludeSystemDatabases bit = 1,
    @Sql varchar(max) OUTPUT
)
AS BEGIN

/**************************************************************************************************************************************
* Lists all of the databases for a given server.
*   Parameters
*       SearchDatabases - Comma delimited list of database names for which to search - converted into series of Like statements
*                         Defaults to null  
*       ExcludeSystemDatabases - 1 to exclude system databases, otherwise 0
*                                Defaults to 1
*       Sql - Output - the stored proc generated sql
*
*   Adapted from answer by 
*   From: How do I list all tables in all databases in SQL Server in a single result set?
*   Link: https://stackoverflow.com/questions/2875768/how-do-i-list-all-tables-in-all-databases-in-sql-server-in-a-single-result-set
*
**************************************************************************************************************************************/

    SET NOCOUNT ON

    DECLARE @l_CompoundLikeStatement varchar(max) = ''
    DECLARE @l_DatabaseName sysname

    DECLARE @l_Index int

    DECLARE @lUseAndText bit = 0

    DECLARE @l_AllDatabases table (ServerName sysname, DbName sysname)

    SET @Sql = 
        'select @@ServerName as ''ServerName'', ''?'' as ''DbName'''

    IF @SearchDatabases IS NOT NULL BEGIN
        SET @l_CompoundLikeStatement = char(13) + 'where (' + char(13)
        WHILE LEN(LTRIM(RTRIM(@SearchDatabases))) > 0 BEGIN
            SET @l_Index = CHARINDEX(',', @SearchDatabases)
            IF @l_Index = 0 BEGIN
                SET @l_DatabaseName = LTRIM(RTRIM(@SearchDatabases))
            END ELSE BEGIN
                SET @l_DatabaseName = LTRIM(RTRIM(LEFT(@SearchDatabases, @l_Index - 1)))
            END

            SET @SearchDatabases = LTRIM(RTRIM(REPLACE(LTRIM(RTRIM(REPLACE(@SearchDatabases, @l_DatabaseName, ''))), ',', '')))
            SET @l_CompoundLikeStatement = @l_CompoundLikeStatement + char(13) + ' ''?'' like ''' + @l_DatabaseName + '%'' COLLATE Latin1_General_CI_AS or '
        END

        -- Trim trailing Or and add closing right parenthesis )
        SET @l_CompoundLikeStatement = LTRIM(RTRIM(@l_CompoundLikeStatement))
        SET @l_CompoundLikeStatement = LEFT(@l_CompoundLikeStatement, LEN(@l_CompoundLikeStatement) - 2) + ' )'

        SET @Sql = @Sql + char(13) +
            @l_CompoundLikeStatement

        SET @lUseAndText = 1
    END

    IF @ExcludeSystemDatabases = 1 BEGIN
        SET @Sql = @Sql + char(13)
        SET @Sql = @Sql + case when @lUseAndText = 1 THEN '  and ' ELSE 'where ' END +
            '''?'' not in (''master'' COLLATE Latin1_General_CI_AS, ''model'' COLLATE Latin1_General_CI_AS, ''msdb'' COLLATE Latin1_General_CI_AS, ''tempdb'' COLLATE Latin1_General_CI_AS)' 
    END

/*  PRINT @Sql  */

    INSERT INTO @l_AllDatabases 
    EXEC sp_msforeachdb @Sql

    SELECT * FROM @l_AllDatabases ORDER BY DbName
END

Clean out Eclipse workspace metadata

In my case eclipse is not showing parent class function on $this, so I perform below mention points and it starts works:-

I go to my /var/www/ folder and check for .metadata folder (Here check the .log file and it shows) Resource is out of sync with the file system: 1. Go to Eclipse --> Project --> Clean 2. Windows -- preferences --> General --> Workspace --> And set it to "Refresh Automatically"

After that boom - things gets start working :)

If you want to load variables from other files too then ado this :- Eclipse-->Windows-->Preferences-->Php-->Editor-->Content Assist --> and check "show variable from other files"

Then it will show element , variables and other functions also.

From a Sybase Database, how I can get table description ( field names and types)?

sp_tables will also work in isql. It gives you the list of tables in the current database.

Select data from "show tables" MySQL query

Not that I know of, unless you select from INFORMATION_SCHEMA, as others have mentioned.

However, the SHOW command is pretty flexible, E.g.:

SHOW tables like '%s%'

How to find available directory objects on Oracle 11g system?

The ALL_DIRECTORIES data dictionary view will have information about all the directories that you have access to. That includes the operating system path

SELECT owner, directory_name, directory_path
  FROM all_directories

How do you determine what SQL Tables have an identity column programmatically

Another potential way to do this for SQL Server, which has less reliance on the system tables (which are subject to change, version to version) is to use the INFORMATION_SCHEMA views:

select COLUMN_NAME, TABLE_NAME
from INFORMATION_SCHEMA.COLUMNS
where COLUMNPROPERTY(object_id(TABLE_SCHEMA+'.'+TABLE_NAME), COLUMN_NAME, 'IsIdentity') = 1
order by TABLE_NAME 

How to list the tables in a SQLite database file that was opened with ATTACH?

It appears you need to go through the sqlite_master table, like this:

SELECT * FROM dbname.sqlite_master WHERE type='table';

And then manually go through each table with a SELECT or similar to look at the rows.

The .DUMP and .SCHEMA commands doesn't appear to see the database at all.

List of foreign keys and the tables they reference in Oracle DB

For Load UserTable (List of foreign keys and the tables they reference)

WITH

reference_view AS
     (SELECT a.owner, a.table_name, a.constraint_name, a.constraint_type,
             a.r_owner, a.r_constraint_name, b.column_name
        FROM dba_constraints a, dba_cons_columns b
       WHERE 
          a.owner = b.owner
         AND a.constraint_name = b.constraint_name
         AND constraint_type = 'R'),
constraint_view AS
     (SELECT a.owner a_owner, a.table_name, a.column_name, b.owner b_owner,
             b.constraint_name
        FROM dba_cons_columns a, dba_constraints b
       WHERE a.owner = b.owner
         AND a.constraint_name = b.constraint_name
         AND b.constraint_type = 'P'

         ) ,
usertableviewlist AS 
(
      select  TABLE_NAME  from user_tables  
) 
SELECT  
       rv.table_name FK_Table , rv.column_name FK_Column ,
       CV.table_name PK_Table , rv.column_name PK_Column , rv.r_constraint_name Constraint_Name 
  FROM reference_view rv, constraint_view CV , usertableviewlist UTable
 WHERE rv.r_constraint_name = CV.constraint_name AND rv.r_owner = CV.b_owner And UTable.TABLE_NAME = rv.table_name; 

Sql Query to list all views in an SQL Server 2005 database

To finish the set off (with what has already been suggested):

SELECT * FROM sys.views

This gives extra properties on each view, not available from sys.objects (which contains properties common to all types of object) or INFORMATION_SCHEMA.VIEWS. Though INFORMATION_SCHEMA approach does provide the view definition out-of-the-box.

How do I find the date a video (.AVI .MP4) was actually recorded?

The existence of that piece of metadata is entirely dependent on the application that wrote the file. It's very common to load up JPG files with metadata (EXIF tags) about the file, such as a timestamp or camera information or geolocation. ID3 tags in MP3 files are also very common. But it's a lot less common to see this kind of metadata in video files.

If you just need a tool to read this data from files manually, GSpot might do the trick: http://www.videohelp.com/tools/Gspot

If you want to read this in code then I imagine each container format is going to have its own standards and each one will take a bit of research and implementation to support.

How do I start a program with arguments when debugging?

I would suggest using the directives like the following:

        static void Main(string[] args)
        {
#if DEBUG
            args = new[] { "A" };
#endif

            Console.WriteLine(args[0]);
        }

Good luck!

string in namespace std does not name a type

Nouns.h doesn't include <string>, but it needs to. You need to add

#include <string>

at the top of that file, otherwise the compiler doesn't know what std::string is when it is encountered for the first time.

SQL Server Configuration Manager not found

I know this is old but you can directly browse it using this paths..

SQL Server 2019 C:\Windows\SysWOW64\SQLServerManager15.msc

SQL Server 2017 C:\Windows\SysWOW64\SQLServerManager14.msc

SQL Server 2016 C:\Windows\SysWOW64\SQLServerManager13.msc

SQL Server 2014 C:\Windows\SysWOW64\SQLServerManager12.msc

SQL Server 2012 C:\Windows\SysWOW64\SQLServerManager11.msc

SQL Server 2008 C:\Windows\SysWOW64\SQLServerManager10.msc

source is from ms site https://msdn.microsoft.com/en-us/library/ms174212.aspx

One can also specify %systemroot% for the path of Windows directory. For example:

SQL Server 2019: %systemroot%\SysWOW64\SQLServerManager15.msc

How to increase the timeout period of web service in asp.net?

you can do this in different ways:

  1. Setting a timeout in the web service caller from code (not 100% sure but I think I have seen this done);
  2. Setting a timeout in the constructor of the web service proxy in the web references;
  3. Setting a timeout in the server side, web.config of the web service application.

see here for more details on the second case:

http://msdn.microsoft.com/en-us/library/ff647786.aspx#scalenetchapt10_topic14

and here for details on the last case:

How to increase the timeout to a web service request?

Custom fonts and XML layouts (Android)

It may be useful to know that starting from Android 8.0 (API level 26) you can use a custom font in XML.

You can apply a custom font to the entire application in the following way.

  1. Put the font in the folder res/font.

  2. In res/values/styles.xml use it in the application theme. <style name="AppTheme" parent="{whatever you like}"> <item name="android:fontFamily">@font/myfont</item> </style>

How to expand and compute log(a + b)?

In general, one doesn't expand out log(a + b); you just deal with it as is. That said, there are occasionally circumstances where it makes sense to use the following identity:

log(a + b) = log(a * (1 + b/a)) = log a + log(1 + b/a)

(In fact, this identity is often used when implementing log in math libraries).

How to hide code from cells in ipython notebook visualized with nbviewer?

There is a nice solution provided here that works well for notebooks exported to HTML. The website even links back here to this SO post, but I don't see Chris's solution here! (Chris, where are you at?)

This is basically the same solution as the accepted answer from harshil, but it has the advantage of hiding the toggle code itself in the exported HTML. I also like that this approach avoids the need for the IPython HTML function.

To implement this solution, add the following code to a 'Raw NBConvert' cell at the top of your notebook:

<script>
  function code_toggle() {
    if (code_shown){
      $('div.input').hide('500');
      $('#toggleButton').val('Show Code')
    } else {
      $('div.input').show('500');
      $('#toggleButton').val('Hide Code')
    }
    code_shown = !code_shown
  }

  $( document ).ready(function(){
    code_shown=false;
    $('div.input').hide()
  });
</script>
<form action="javascript:code_toggle()">
  <input type="submit" id="toggleButton" value="Show Code">
</form>

Then simply export the notebook to HTML. There will be a toggle button at the top of the notebook to show or hide the code.

Chris also provides an example here.

I can verify that this works in Jupyter 5.0.0

Update: It is also convenient to show/hide the div.prompt elements along with the div.input elements. This removes the In [##]: and Out: [##] text and reduces the margins on the left.

Appending items to a list of lists in python

Python lists are mutable objects and here:

plot_data = [[]] * len(positions) 

you are repeating the same list len(positions) times.

>>> plot_data = [[]] * 3
>>> plot_data
[[], [], []]
>>> plot_data[0].append(1)
>>> plot_data
[[1], [1], [1]]
>>> 

Each list in your list is a reference to the same object. You modify one, you see the modification in all of them.

If you want different lists, you can do this way:

plot_data = [[] for _ in positions]

for example:

>>> pd = [[] for _ in range(3)]
>>> pd
[[], [], []]
>>> pd[0].append(1)
>>> pd
[[1], [], []]

Bootstrap datepicker hide after selection

You can change source code, bootstrap-datepicker.js. Add this.hide(); like ne

  if (this.viewMode !== 0) {
    this.date = new Date(this.viewDate);
    this.element.trigger({
        type: 'changeDate',
        date: this.date,
        viewMode: DPGlobal.modes[this.viewMode].clsName
    });
    this.hide();//here
 }

What is the best way to uninstall gems from a rails3 project?

This will uninstall a gem installed by bundler:

bundle exec gem uninstall GEM_NAME

Note that this throws

ERROR: While executing gem ... (NoMethodError) undefined method `delete' for #<Bundler::SpecSet:0x00000101142268>

but the gem is actually removed. Next time you run bundle install the gem will be reinstalled.

How can I add a column that doesn't allow nulls in a Postgresql database?

Since rows already exist in the table, the ALTER statement is trying to insert NULL into the newly created column for all of the existing rows. You would have to add the column as allowing NULL, then fill the column with the values you want, and then set it to NOT NULL afterwards.

Pass in an array of Deferreds to $.when()

If you're transpiling and have access to ES6, you can use spread syntax which specifically applies each iterable item of an object as a discrete argument, just the way $.when() needs it.

$.when(...deferreds).done(() => {
    // do stuff
});

MDN Link - Spread Syntax

Effect of using sys.path.insert(0, path) and sys.path(append) when loading modules

Because python checks in the directories in sequential order starting at the first directory in sys.path list, till it find the .py file it was looking for.

Ideally, the current directory or the directory of the script is the first always the first element in the list, unless you modify it, like you did. From documentation -

As initialized upon program startup, the first item of this list, path[0], is the directory containing the script that was used to invoke the Python interpreter. If the script directory is not available (e.g. if the interpreter is invoked interactively or if the script is read from standard input), path[0] is the empty string, which directs Python to search modules in the current directory first. Notice that the script directory is inserted before the entries inserted as a result of PYTHONPATH.

So, most probably, you had a .py file with the same name as the module you were trying to import from, in the current directory (where the script was being run from).

Also, a thing to note about ImportErrors , lets say the import error says - ImportError: No module named main - it doesn't mean the main.py is overwritten, no if that was overwritten we would not be having issues trying to read it. Its some module above this that got overwritten with a .py or some other file.

Example -

My directory structure looks like -

 - test
    - shared
         - __init__.py
         - phtest.py
  - testmain.py

Now From testmain.py , I call from shared import phtest , it works fine.

Now lets say I introduce a shared.py in test directory` , example -

 - test
    - shared
         - __init__.py
         - phtest.py
  - testmain.py 
  - shared.py

Now when I try to do from shared import phtest from testmain.py , I will get the error -

ImportError: cannot import name 'phtest'

As you can see above, the file that is causing the issue is shared.py , not phtest.py .

How to run python script in webpage

With your current requirement this would work :

    def start_html():
        return '<html>'

    def end_html():
        return '</html>'

    def print_html(text):
        text = str(text)
        text = text.replace('\n', '<br>')
        return '<p>' + str(text) + '</p>'
if __name__ == '__main__':
        webpage_data =  start_html()
        webpage_data += print_html("Hi Welcome to Python test page\n")
        webpage_data += fd.write(print_html("Now it will show a calculation"))
        webpage_data += print_html("30+2=")
        webpage_data += print_html(30+2)
        webpage_data += end_html()
        with open('index.html', 'w') as fd: fd.write(webpage_data)

open the index.html and you will see what you want

Remove special symbols and extra spaces and replace with underscore using the replace method

If you have a text as

var sampleText ="ä_öü_ßÄ_ TESTED Ö_Ü!@#$%^&())(&&++===.XYZ"

To replace all special character (!@#$%^&())(&&++= ==.) without replacing the characters(including umlaut)

Use below regex

sampleText = sampleText.replace(/[`~!@#$%^&*()|+-=?;:'",.<>{}[]\/\s]/gi,'');

OUTPUT : sampleText = "ä_öü_ßÄ____TESTED_Ö_Ü_____________________XYZ"

This would replace all with an underscore which is provided as second argument to the replace function.You can add whatever you want as per your requirement

Show tables, describe tables equivalent in redshift

All the information can be found in a PG_TABLE_DEF table, documentation.

Listing all tables in a public schema (default) - show tables equivalent:

SELECT DISTINCT tablename
FROM pg_table_def
WHERE schemaname = 'public'
ORDER BY tablename;

Description of all the columns from a table called table_name - describe table equivalent:

SELECT *
FROM pg_table_def
WHERE tablename = 'table_name'
AND schemaname = 'public';

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

This kind of JOIN is not optimizable to a HASH JOIN or a MERGE JOIN.

It can be expressed as a concatenation of two resultsets:

SELECT  *
FROM    maintable m
JOIN    othertable o
ON      o.parentId = m.id
UNION
SELECT  *
FROM    maintable m
JOIN    othertable o
ON      o.id = m.parentId

, each of them being an equijoin, however, SQL Server's optimizer is not smart enough to see it in the query you wrote (though they are logically equivalent).

How to make a redirection on page load in JSF 1.x

Edit 2

I finally found a solution by implementing my forward action like that:

private void applyForward() {
    FacesContext facesContext = FacesContext.getCurrentInstance();
    // Find where to redirect the user.
    String redirect = getTheFromOutCome();

    // Change the Navigation context.
    NavigationHandler myNav = facesContext.getApplication().getNavigationHandler();
    myNav.handleNavigation(facesContext, null, redirect);

    // Update the view root
    UIViewRoot vr = facesContext.getViewRoot();
    if (vr != null) {
        // Get the URL where to redirect the user
        String url = facesContext.getExternalContext().getRequestContextPath();
        url = url + "/" + vr.getViewId().replace(".xhtml", ".jsf");
        Object obj = facesContext.getExternalContext().getResponse();
        if (obj instanceof HttpServletResponse) {
            HttpServletResponse response = (HttpServletResponse) obj;
            try {
                // Redirect the user now.
                response.sendRedirect(response.encodeURL(url));
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }
}

It works (at least regarding my first tests), but I still don't like the way it is implemented... Any better idea?


Edit This solution does not work. Indeed, when the doForward() function is called, the JSF lifecycle has already been started, and then recreate a new request is not possible.


One idea to solve this issue, but I don't really like it, is to force the doForward() action during one of the setBindedInputHidden() method:

private boolean actionDefined = false;
private boolean actionParamDefined = false;

public void setHiddenActionParam(HtmlInputHidden hiddenActionParam) {
    this.hiddenActionParam = hiddenActionParam;
    String actionParam = FacesContext.getCurrentInstance().getExternalContext().getRequestParameterMap().get("actionParam");
    this.hiddenActionParam.setValue(actionParam);
    actionParamDefined = true;
    forwardAction();
}

public void setHiddenAction(HtmlInputHidden hiddenAction) {
    this.hiddenAction = hiddenAction;
    String action = FacesContext.getCurrentInstance().getExternalContext().getRequestParameterMap().get("action");
    this.hiddenAction.setValue(action);
    actionDefined = true;
    forwardAction();
}

private void forwardAction() {
    if (!actionDefined || !actionParamDefined) {
        // As one of the inputHidden was not binded yet, we do nothing...
        return;
    }
    // Now, both action and actionParam inputHidden are binded, we can execute the forward...
    doForward(null);
}

This solution does not involve any Javascript call, and works does not work.

Check if option is selected with jQuery, if not select a default

lencioni's answer is what I'd recommend. You can change the selector for the option ('#mySelect option:last') to select the option with a specific value using "#mySelect option[value='yourDefaultValue']". More on selectors.

If you're working extensively with select lists on the client check out this plugin: http://www.texotela.co.uk/code/jquery/select/. Take a look the source if you want to see some more examples of working with select lists.

How to make an AJAX call without jQuery?

<html>
  <script>
    var xmlDoc = null ;

  function load() {
    if (typeof window.ActiveXObject != 'undefined' ) {
      xmlDoc = new ActiveXObject("Microsoft.XMLHTTP");
      xmlDoc.onreadystatechange = process ;
    }
    else {
      xmlDoc = new XMLHttpRequest();
      xmlDoc.onload = process ;
    }
    xmlDoc.open( "GET", "background.html", true );
    xmlDoc.send( null );
  }

  function process() {
    if ( xmlDoc.readyState != 4 ) return ;
    document.getElementById("output").value = xmlDoc.responseText ;
  }

  function empty() {
    document.getElementById("output").value = '<empty>' ;
  }
</script>

<body>
  <textarea id="output" cols='70' rows='40'><empty></textarea>
  <br></br>
  <button onclick="load()">Load</button> &nbsp;
  <button onclick="empty()">Clear</button>
</body>
</html>

How do I overload the square-bracket operator in C#?

For CLI C++ (compiled with /clr) see this MSDN link.

In short, a property can be given the name "default":

ref class Class
{
 public:
  property System::String^ default[int i]
  {
    System::String^ get(int i) { return "hello world"; }
  }
};

Why does configure say no C compiler found when GCC is installed?

I had the same issue with mind. I tried using sudo apt-get install build-essential It still won't work. I simply created a hardlink to the gcc-x binary in the /usr/bin/ folder. sudo ls /usr/bin/gcc-x /usr/bin/gcc

That worked for me!

Sending data from HTML form to a Python script in Flask

The form tag needs some attributes set:

  1. action: The URL that the form data is sent to on submit. Generate it with url_for. It can be omitted if the same URL handles showing the form and processing the data.
  2. method="post": Submits the data as form data with the POST method. If not given, or explicitly set to get, the data is submitted in the query string (request.args) with the GET method instead.
  3. enctype="multipart/form-data": When the form contains file inputs, it must have this encoding set, otherwise the files will not be uploaded and Flask won't see them.

The input tag needs a name parameter.

Add a view to handle the submitted data, which is in request.form under the same key as the input's name. Any file inputs will be in request.files.

@app.route('/handle_data', methods=['POST'])
def handle_data():
    projectpath = request.form['projectFilepath']
    # your code
    # return a response

Set the form's action to that view's URL using url_for:

<form action="{{ url_for('handle_data') }}" method="post">
    <input type="text" name="projectFilepath">
    <input type="submit">
</form>

getting the difference between date in days in java

Like this.

import java.util.Date;
import java.util.GregorianCalendar;

/**
 * DateDiff -- compute the difference between two dates.
 */
public class DateDiff {
  public static void main(String[] av) {
    /** The date at the end of the last century */
    Date d1 = new GregorianCalendar(2000, 11, 31, 23, 59).getTime();

    /** Today's date */
    Date today = new Date();

    // Get msec from each, and subtract.
    long diff = today.getTime() - d1.getTime();

    System.out.println("The 21st century (up to " + today + ") is "
        + (diff / (1000 * 60 * 60 * 24)) + " days old.");
  }

}

Here is an article on Java date arithmetic.

Responsive Google Map?

in the iframe tag, you can easily add width='100%' instead of the preset value giving to you by the map

like this:

 <iframe src="https://www.google.com/maps/embed?anyLocation" width="100%" height="400" frameborder="0" style="border:0;" allowfullscreen=""></iframe>

Why I can't change directories using "cd"?

When you fire a shell script, it runs a new instance of that shell (/bin/bash). Thus, your script just fires up a shell, changes the directory and exits. Put another way, cd (and other such commands) within a shell script do not affect nor have access to the shell from which they were launched.

Color theme for VS Code integrated terminal

The best colors I've found --which aside from being so beautiful, are very easy to look at too and do not boil my eyes-- are the ones I've found listed in this GitHub repository: VSCode Snazzy

Very Easy Installation:

Copy the contents of snazzy.json into your VS Code "settings.json" file.

(In case you don't know how to open the "settings.json" file, first hit Ctrl+Shift+P and then write Preferences: open settings(JSON) and hit enter).


Notice: For those who have tried ColorTool and it works outside VSCode but not inside VSCode, you've made no mistakes in implementing it, that's just a decision of VSCode developers for the VSCode's terminal to be colored independently.

Instagram how to get my user id from username?

Working solution without access token as of October-14-2018:

Search for the username:

https://www.instagram.com/web/search/topsearch/?query=<username>

Example:

https://www.instagram.com/web/search/topsearch/?query=therock

This is a search query. Find the exact matched entry in the reply and get user ID from the entry.

Extracting numbers from vectors of strings

Or simply:

as.numeric(gsub("\\D", "", years))
# [1] 20  1

Hide HTML element by id

@Adam Davis, the code you entered is actually a jQuery call. If you already have the library loaded, that works just fine, otherwise you will need to append the CSS

<style type="text/css">
    #nav-ask{ display:none; }
</style>

or if you already have a "hideMe" CSS Class:

<script type="text/javascript">

    if(document.getElementById && document.createTextNode)
    {
        if(document.getElementById('nav-ask'))
        {
            document.getElementById('nav-ask').className='hideMe';
        }
    }

</script>

How to use ArrayList.addAll()?

Collections.addAll is what you want.

Collections.addAll(myArrayList, '+', '-', '*', '^');

Another option is to pass the list into the constructor using Arrays.asList like this:

List<Character> myArrayList = new ArrayList<Character>(Arrays.asList('+', '-', '*', '^'));

If, however, you are good with the arrayList being fixed-length, you can go with the creation as simple as list = Arrays.asList(...). Arrays.asList specification states that it returns a fixed-length list which acts as a bridge to the passed array, which could be not what you need.

Submit a form in a popup, and then close the popup

I know this is an old question, but I stumbled across it when I was having a similar issue, and just wanted to share how I ended achieving the results you requested so future people can pick what works best for their situation.

First, I utilize the onsubmit event in the form, and pass this to the function to make it easier to deal with this particular form.

<form action="/system/wpacert" onsubmit="return closeSelf(this);" method="post" enctype="multipart/form-data"  name="certform">
    <div>Certificate 1: <input type="file" name="cert1"/></div>
    <div>Certificate 2: <input type="file" name="cert2"/></div>
    <div>Certificate 3: <input type="file" name="cert3"/></div>

    <div><input type="submit" value="Upload"/></div>
</form>

In our function, we'll submit the form data, and then we'll close the window. This will allow it to submit the data, and once it's done, then it'll close the window and return you to your original window.

<script type="text/javascript">
  function closeSelf (f) {
     f.submit();
     window.close();
  }
</script>

Hope this helps someone out. Enjoy!


Option 2: This option will let you submit via AJAX, and if it's successful, it'll close the window. This prevents windows from closing prior to the data being submitted. Credits to http://jquery.malsup.com/form/ for their work on the jQuery Form Plugin

First, remove your onsubmit/onclick events from the form/submit button. Place an ID on the form so AJAX can find it.

<form action="/system/wpacert" method="post" enctype="multipart/form-data"  id="certform">
    <div>Certificate 1: <input type="file" name="cert1"/></div>
    <div>Certificate 2: <input type="file" name="cert2"/></div>
    <div>Certificate 3: <input type="file" name="cert3"/></div>

    <div><input type="submit" value="Upload"/></div>
</form>

Second, you'll want to throw this script at the bottom, don't forget to reference the plugin. If the form submission is successful, it'll close the window.

<script src="http://ajax.googleapis.com/ajax/libs/jquery/1.7/jquery.js"></script> 
<script src="http://malsup.github.com/jquery.form.js"></script> 

    <script>
       $(document).ready(function () {
          $('#certform').ajaxForm(function () {
          window.close();
          });
       });
    </script>

Java AES and using my own Key

This wll work.

public class CryptoUtils {

    private  final String TRANSFORMATION = "AES";
    private  final String encodekey = "1234543444555666";
    public  String encrypt(String inputFile)
            throws CryptoException {
        return doEncrypt(encodekey, inputFile);
    }


    public  String decrypt(String input)
            throws CryptoException {
    // return  doCrypto(Cipher.DECRYPT_MODE, key, inputFile);
    return doDecrypt(encodekey,input);
    }

    private  String doEncrypt(String encodekey, String inputStr)   throws CryptoException {
        try {

            Cipher cipher = Cipher.getInstance(TRANSFORMATION);

            byte[] key = encodekey.getBytes("UTF-8");
            MessageDigest sha = MessageDigest.getInstance("SHA-1");
            key = sha.digest(key);
            key = Arrays.copyOf(key, 16); // use only first 128 bit

            SecretKeySpec secretKeySpec = new SecretKeySpec(key, "AES");

            cipher.init(Cipher.ENCRYPT_MODE, secretKeySpec);

            byte[] inputBytes = inputStr.getBytes();     
            byte[] outputBytes = cipher.doFinal(inputBytes);

            return Base64Utils.encodeToString(outputBytes);

        } catch (NoSuchPaddingException | NoSuchAlgorithmException
                | InvalidKeyException | BadPaddingException
                | IllegalBlockSizeException | IOException ex) {
            throw new CryptoException("Error encrypting/decrypting file", ex);
       }
     }


    public  String doDecrypt(String encodekey,String encrptedStr) { 
          try {     

              Cipher dcipher = Cipher.getInstance(TRANSFORMATION);
              dcipher = Cipher.getInstance("AES");
              byte[] key = encodekey.getBytes("UTF-8");
              MessageDigest sha = MessageDigest.getInstance("SHA-1");
              key = sha.digest(key);
              key = Arrays.copyOf(key, 16); // use only first 128 bit

              SecretKeySpec secretKeySpec = new SecretKeySpec(key, "AES");

              dcipher.init(Cipher.DECRYPT_MODE, secretKeySpec);
            // decode with base64 to get bytes

              byte[] dec = Base64Utils.decode(encrptedStr.getBytes());  
              byte[] utf8 = dcipher.doFinal(dec);

              // create new string based on the specified charset
              return new String(utf8, "UTF8");

          } catch (Exception e) {

            e.printStackTrace();

          }
      return null;
      }
 }

Read input from a JOptionPane.showInputDialog box

Your problem is that, if the user clicks cancel, operationType is null and thus throws a NullPointerException. I would suggest that you move

if (operationType.equalsIgnoreCase("Q")) 

to the beginning of the group of if statements, and then change it to

if(operationType==null||operationType.equalsIgnoreCase("Q")). 

This will make the program exit just as if the user had selected the quit option when the cancel button is pushed.

Then, change all the rest of the ifs to else ifs. This way, once the program sees whether or not the input is null, it doesn't try to call anything else on operationType. This has the added benefit of making it more efficient - once the program sees that the input is one of the options, it won't bother checking it against the rest of them.

How to install XNA game studio on Visual Studio 2012?

On codeplex was released new XNA Extension for Visual Studio 2012/2013. You can download it from: https://msxna.codeplex.com/releases

Best practices for adding .gitignore file for Python projects?

Covers most of the general stuff -

# Byte-compiled / optimized / DLL files
__pycache__/
*.py[cod]
*$py.class

# C extensions
*.so

# Distribution / packaging
.Python
build/
develop-eggs/
dist/
downloads/
eggs/
.eggs/
lib/
lib64/
parts/
sdist/
var/
wheels/
*.egg-info/
.installed.cfg
*.egg
MANIFEST

# PyInstaller
#  Usually these files are written by a python script from a template
#  before PyInstaller builds the exe, so as to inject date/other infos into it.
*.manifest
*.spec

# Installer logs
pip-log.txt
pip-delete-this-directory.txt

# Unit test / coverage reports
htmlcov/
.tox/
.coverage
.coverage.*
.cache
nosetests.xml
coverage.xml
*.cover
.hypothesis/
.pytest_cache/

# Translations
*.mo
*.pot

# Django stuff:
*.log
local_settings.py
db.sqlite3

# Flask stuff:
instance/
.webassets-cache

# Scrapy stuff:
.scrapy

# Sphinx documentation
docs/_build/

# PyBuilder
target/

# Jupyter Notebook
.ipynb_checkpoints

# pyenv
.python-version

# celery beat schedule file
celerybeat-schedule

# SageMath parsed files
*.sage.py

# Environments
.env
.venv
env/
venv/
ENV/
env.bak/
venv.bak/

# Spyder project settings
.spyderproject
.spyproject

# Rope project settings
.ropeproject

# mkdocs documentation
/site

# mypy
.mypy_cache/

Reference: python .gitignore

Username and password in command for git push

For anyone having issues with passwords with special chars just omit the password and it will prompt you for it:

git push https://[email protected]/YOUR_GIT_USERNAME/yourGitFileName.git

Select <a> which href ends with some string

$("a[href*='id=ABC']").addClass('active_jquery_menu');

How to convert a String to JsonObject using gson library

JsonObject jsonObject = (JsonObject) new JsonParser().parse("YourJsonString");

How to turn a vector into a matrix in R?

Just use matrix:

matrix(vec,nrow = 7,ncol = 7)

One advantage of using matrix rather than simply altering the dimension attribute as Gavin points out, is that you can specify whether the matrix is filled by row or column using the byrow argument in matrix.

.do extension in web pages?

I've occasionally thought that it might serve a purpose to add a layer of security by obscuring the back-end interpreter through a remapping of .php or whatever to .aspx or whatever so that any potential hacker would be sent down the wrong path, at least for a while. I never bothered to try it and I don't do a lot of webserver work any more so I'm unlikely to.

However, I'd be interested in the perspective of an experienced server admin on that notion.

How to serialize Object to JSON?

GSON is easy to use and has relatively small memory footprint. If you loke to have even smaller footprint, you can grab:

https://github.com/ko5tik/jsonserializer

Which is tiny wrapper around stripped down GSON libraries for just POJOs

How do I output coloured text to a Linux terminal?

on OSX shell, this works for me (including 2 spaces in front of "red text"):

$ printf "\e[033;31m  red text\n"
$ echo "$(tput setaf 1)  red text"

How to get a thread and heap dump of a Java process on Windows that's not running in a console

You have to redirect output from second java executable to some file. Then, use SendSignal to send "-3" to your second process.

How do I get interactive plots again in Spyder/IPython/matplotlib?

After applying : Tools > preferences > Graphics > Backend > Automatic Just restart the kernel enter image description here

And you will surely get Interactive Plot. Happy Coding!

How to empty a Heroku database

I always do this with the one-liner 'heroku pg:reset DATABASE'.

Resetting a setTimeout

clearTimeout() and feed the reference of the setTimeout, which will be a number. Then re-invoke it:

var initial;

function invocation() {
    alert('invoked')
    initial = window.setTimeout( 
    function() {
        document.body.style.backgroundColor = 'black'
    }, 5000);
}

invocation();

document.body.onclick = function() {
    alert('stopped')
    clearTimeout( initial )
    // re-invoke invocation()
}

In this example, if you don't click on the body element in 5 seconds the background color will be black.

Reference:

Note: setTimeout and clearTimeout are not ECMAScript native methods, but Javascript methods of the global window namespace.

String to date in Oracle with milliseconds

Oracle stores only the fractions up to second in a DATE field.

Use TIMESTAMP instead:

SELECT  TO_TIMESTAMP('2004-09-30 23:53:48,140000000', 'YYYY-MM-DD HH24:MI:SS,FF9')
FROM    dual

, possibly casting it to a DATE then:

SELECT  CAST(TO_TIMESTAMP('2004-09-30 23:53:48,140000000', 'YYYY-MM-DD HH24:MI:SS,FF9') AS DATE)
FROM    dual

"Object doesn't support this property or method" error in IE11

Best way to solve this until a fix is available (if a fix comes) is to force IE compatibility mode on the user.

Use <META http-equiv="X-UA-Compatible" content="IE=9"> ideally in the masterpage so all pages in your site get the workaround.

Which JDK version (Language Level) is required for Android Studio?

Answer Clarification - Android Studio supports JDK8

The following is an answer to the question "What version of Java does Android support?" which is different from "What version of Java can I use to run Android Studio?" which is I believe what was actually being asked. For those looking to answer the 2nd question, you might find Using Android Studio with Java 1.7 helpful.

Also: See http://developer.android.com/sdk/index.html#latest for Android Studio system requirements. JDK8 is actually a requirement for PC and linux (as of 5/14/16).


Java 8 update (3/19/14)

Because I'd assume this question will start popping up soon with the release yesterday: As of right now, there's no set date for when Android will support Java 8.

Here's a discussion over at /androiddev - http://www.reddit.com/r/androiddev/comments/22mh0r/does_android_have_any_plans_for_java_8/

If you really want lambda support, you can checkout Retrolambda - https://github.com/evant/gradle-retrolambda. I've never used it, but it seems fairly promising.

Another Update: Android added Java 7 support

Android now supports Java 7 (minus try-with-resource feature). You can read more about the Java 7 features here: https://stackoverflow.com/a/13550632/413254. If you're using gradle, you can add the following in your build.gradle:

android {
    compileOptions {
        sourceCompatibility JavaVersion.VERSION_1_7
        targetCompatibility JavaVersion.VERSION_1_7
    }
}

Older response

I'm using Java 7 with Android Studio without any problems (OS X - 10.8.4). You need to make sure you drop the project language level down to 6.0 though. See the screenshot below.

enter image description here

What tehawtness said below makes sense, too. If they're suggesting JDK 6, it makes sense to just go with JDK 6. Either way will be fine.

enter image description here


Update: See this SO post -- https://stackoverflow.com/a/9567402/413254

Pandas convert dataframe to array of tuples

#try this one:

tuples = list(zip(data_set["data_date"], data_set["data_1"],data_set["data_2"]))
print (tuples)

Reading and writing to serial port in C on Linux

1) I'd add a /n after init. i.e. write( USB, "init\n", 5);

2) Double check the serial port configuration. Odds are something is incorrect in there. Just because you don't use ^Q/^S or hardware flow control doesn't mean the other side isn't expecting it.

3) Most likely: Add a "usleep(100000); after the write(). The file-descriptor is set not to block or wait, right? How long does it take to get a response back before you can call read? (It has to be received and buffered by the kernel, through system hardware interrupts, before you can read() it.) Have you considered using select() to wait for something to read()? Perhaps with a timeout?

Edited to Add:

Do you need the DTR/RTS lines? Hardware flow control that tells the other side to send the computer data? e.g.

int tmp, serialLines;

cout << "Dropping Reading DTR and RTS\n";
ioctl ( readFd, TIOCMGET, & serialLines );
serialLines &= ~TIOCM_DTR;
serialLines &= ~TIOCM_RTS;
ioctl ( readFd, TIOCMSET, & serialLines );
usleep(100000);
ioctl ( readFd, TIOCMGET, & tmp );
cout << "Reading DTR status: " << (tmp & TIOCM_DTR) << endl;
sleep (2);

cout << "Setting Reading DTR and RTS\n";
serialLines |= TIOCM_DTR;
serialLines |= TIOCM_RTS;
ioctl ( readFd, TIOCMSET, & serialLines );
ioctl ( readFd, TIOCMGET, & tmp );
cout << "Reading DTR status: " << (tmp & TIOCM_DTR) << endl;

Setting the height of a SELECT in IE

You can use a replacement: jQuery Chosen. It looks pretty awesome.

How can I find last row that contains data in a specific column?

All the solutions relying on built-in behaviors (like .Find and .End) have limitations that are not well-documented (see my other answer for details).

I needed something that:

  • Finds the last non-empty cell (i.e. that has any formula or value, even if it's an empty string) in a specific column
  • Relies on primitives with well-defined behavior
  • Works reliably with autofilters and user modifications
  • Runs as fast as possible on 10,000 rows (to be run in a Worksheet_Change handler without feeling sluggish)
  • ...with performance not falling off a cliff with accidental data or formatting put at the very end of the sheet (at ~1M rows)

The solution below:

  • Uses UsedRange to find the upper bound for the row number (to make the search for the true "last row" fast in the common case where it's close to the end of the used range);
  • Goes backwards to find the row with data in the given column;
  • ...using VBA arrays to avoid accessing each row individually (in case there are many rows in the UsedRange we need to skip)

(No tests, sorry)

' Returns the 1-based row number of the last row having a non-empty value in the given column (0 if the whole column is empty)
Private Function getLastNonblankRowInColumn(ws As Worksheet, colNo As Integer) As Long
    ' Force Excel to recalculate the "last cell" (the one you land on after CTRL+END) / "used range"
    ' and get the index of the row containing the "last cell". This is reasonably fast (~1 ms/10000 rows of a used range)
    Dim lastRow As Long: lastRow = ws.UsedRange.Rows(ws.UsedRange.Rows.Count).Row - 1 ' 0-based

    ' Since the "last cell" is not necessarily the one we're looking for (it may be in a different column, have some
    ' formatting applied but no value, etc), we loop backward from the last row towards the top of the sheet).
    Dim wholeRng As Range: Set wholeRng = ws.Columns(colNo)

    ' Since accessing cells one by one is slower than reading a block of cells into a VBA array and looping through the array,
    ' we process in chunks of increasing size, starting with 1 cell and doubling the size on each iteration, until MAX_CHUNK_SIZE is reached.
    ' In pathological cases where Excel thinks all the ~1M rows are in the used range, this will take around 100ms.
    ' Yet in a normal case where one of the few last rows contains the cell we're looking for, we don't read too many cells.
    Const MAX_CHUNK_SIZE = 2 ^ 10 ' (using large chunks gives no performance advantage, but uses more memory)
    Dim chunkSize As Long: chunkSize = 1
    Dim startOffset As Long: startOffset = lastRow + 1 ' 0-based
    Do ' Loop invariant: startOffset>=0 and all rows after startOffset are blank (i.e. wholeRng.Rows(i+1) for i>=startOffset)
        startOffset = IIf(startOffset - chunkSize >= 0, startOffset - chunkSize, 0)
        ' Fill `vals(1 To chunkSize, 1 To 1)` with column's rows indexed `[startOffset+1 .. startOffset+chunkSize]` (1-based, inclusive)
        Dim chunkRng As Range: Set chunkRng = wholeRng.Resize(chunkSize).Offset(startOffset)
        Dim vals() As Variant
        If chunkSize > 1 Then
            vals = chunkRng.Value2
        Else ' reading a 1-cell range requires special handling <http://www.cpearson.com/excel/ArraysAndRanges.aspx>
            ReDim vals(1 To 1, 1 To 1)
            vals(1, 1) = chunkRng.Value2
        End If

        Dim i As Long
        For i = UBound(vals, 1) To LBound(vals, 1) Step -1
            If Not IsEmpty(vals(i, 1)) Then
                getLastNonblankRowInColumn = startOffset + i
                Exit Function
            End If
        Next i

        If chunkSize < MAX_CHUNK_SIZE Then chunkSize = chunkSize * 2
    Loop While startOffset > 0

    getLastNonblankRowInColumn = 0
End Function

What's the difference between lists enclosed by square brackets and parentheses in Python?

Comma-separated items enclosed by ( and ) are tuples, those enclosed by [ and ] are lists.

How to close a GUI when I push a JButton?

JButton close = new JButton("Close");
close.addActionListener(this);
public void actionPerformed(ActionEvent closing) { 
// getSource() checks for the source of clicked Button , compares with the name of button in which here is close .     
if(closing.getSource()==close)
   System.exit(0);
   // This exit Your GUI 
}
/*Some Answers were asking for @override which is overriding the method the super class or the parent class and creating different objects and etc which makes the answer too long . Note : we just need to import java.awt.*; and java.swing.*; and Adding this command : class className implements actionListener{} */

Maven – Always download sources and javadocs

In Netbeans, you can instruct Maven to check javadoc on every project open :

Tools | Options | Java icon | Maven tab | Dependencies category | Check Javadoc drop down set to Every Project Open.

Close and reopen Netbeans and you will see Maven download javadocs in the status bar.

How to replace special characters in a string?

Here is a function I used to remove all possible special characters from the string

let name = name.replace(/[&\/\\#,+()$~%!.„'":*‚^_¤?<>|@ª{«»§}©®™ ]/g, '').toLowerCase();

Bootstrap 3 .img-responsive images are not responsive inside fieldset in FireFox

All you need is width:100% somewhere that applies to the tag as shown by the various answers here.

Using col-xs-12:

<!-- adds float:left, which is usually not a problem -->
<img class='img-responsive col-xs-12' />

Or inline CSS:

<img class='img-responsive' style='width:100%;' />

Or, in your own CSS file, add an additional definition for .img-responsive

.img-responsive { 
    width:100%;
}

THE ROOT OF THE PROBLEM

This is a known FF bug that <fieldset> does not respect overflow rules:

https://bugzilla.mozilla.org/show_bug.cgi?id=261037

A CSS "FIX" to fix the FireFox bug would be to make the <fieldset> display:table-column. However, doing so, according to the following link, will cause the display of the fieldset to fail in Opera:

https://github.com/TryGhost/Ghost/issues/789

So, just set your tag to 100% width as described in one of the solutions above.

how to check if a form is valid programmatically using jQuery Validation Plugin

2015 answer: we have this out of the box on modern browsers, just use the HTML5 CheckValidity API from jQuery. I've also made a jquery-html5-validity module to do this:

npm install jquery-html5-validity

Then:

var $ = require('jquery')
require("jquery-html5-validity")($);

then you can run:

$('.some-class').isValid()

true

How to randomize Excel rows

Here's a macro that allows you to shuffle selected cells in a column:

Option Explicit

Sub ShuffleSelectedCells()
  'Do nothing if selecting only one cell
  If Selection.Cells.Count = 1 Then Exit Sub
  'Save selected cells to array
  Dim CellData() As Variant
  CellData = Selection.Value
  'Shuffle the array
  ShuffleArrayInPlace CellData
  'Output array to spreadsheet
  Selection.Value = CellData
End Sub

Sub ShuffleArrayInPlace(InArray() As Variant)
''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
' ShuffleArrayInPlace
' This shuffles InArray to random order, randomized in place.
' Source: http://www.cpearson.com/excel/ShuffleArray.aspx
' Modified by Tom Doan to work with Selection.Value two-dimensional arrays.
''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
  Dim J As Long, _
    N As Long, _
    Temp As Variant
  'Randomize
  For N = LBound(InArray) To UBound(InArray)
    J = CLng(((UBound(InArray) - N) * Rnd) + N)
    If J <> N Then
      Temp = InArray(N, 1)
      InArray(N, 1) = InArray(J, 1)
      InArray(J, 1) = Temp
    End If
  Next N
End Sub

You can read the comments to see what the macro is doing. Here's how to install the macro:

  1. Open the VBA editor (Alt + F11).
  2. Right-click on "ThisWorkbook" under your currently open spreadsheet (listed in parentheses after "VBAProject") and select Insert / Module.
  3. Paste the code above and save the spreadsheet.

Now you can assign the "ShuffleSelectedCells" macro to an icon or hotkey to quickly randomize your selected rows (keep in mind that you can only select one column of rows).

Python Selenium accessing HTML source

By using the page source you will get the whole HTML code.
So first decide the block of code or tag in which you require to retrieve the data or to click the element..

options = driver.find_elements_by_name_("XXX")
for option in options:
    if option.text == "XXXXXX":
        print(option.text)
        option.click()

You can find the elements by name, XPath, id, link and CSS path.

How to upgrade docker container after its image changed

You need to either rebuild all the images and restart all the containers, or somehow yum update the software and restart the database. There is no upgrade path but that you design yourself.

How do synchronized static methods work in Java and can I use it for loading Hibernate entities?

static synchronized means holding lock on the the class's Class object where as synchronized means holding lock on that class's object itself. That means, if you are accessing a non-static synchronized method in a thread (of execution) you still can access a static synchronized method using another thread.

So, accessing two same kind of methods(either two static or two non-static methods) at any point of time by more than a thread is not possible.

chai test array equality doesn't work as expected

For expect, .equal will compare objects rather than their data, and in your case it is two different arrays.

Use .eql in order to deeply compare values. Check out this link.
Or you could use .deep.equal in order to simulate same as .eql.
Or in your case you might want to check .members.

For asserts you can use .deepEqual, link.

Using jQuery, Restricting File Size Before Uploading

I don't think it's possible unless you use a flash, activex or java uploader.

For security reasons ajax / javascript isn't allowed to access the file stream or file properties before or during upload.

Google Maps API warning: NoApiKeys

A key currently still is not required ("required" in the meaning "it will not work without"), but I think there is a good reason for the warning.

But in the documentation you may read now : "All JavaScript API applications require authentication."

I'm sure that it's planned for the future , that Javascript API Applications will not work without a key(as it has been in V2).

You better use a key when you want to be sure that your application will still work in 1 or 2 years.

Java 8 Streams FlatMap method example

It doesn't make sense to flatMap a Stream that's already flat, like the Stream<Integer> you've shown in your question.

However, if you had a Stream<List<Integer>> then it would make sense and you could do this:

Stream<List<Integer>> integerListStream = Stream.of(
    Arrays.asList(1, 2), 
    Arrays.asList(3, 4), 
    Arrays.asList(5)
);

Stream<Integer> integerStream = integerListStream .flatMap(Collection::stream);
integerStream.forEach(System.out::println);

Which would print:

1
2
3
4
5

To do this pre-Java 8 you just need a loops:

List<List<Integer>> integerLists = Arrays.asList(
    Arrays.asList(1, 2), 
    Arrays.asList(3, 4), 
    Arrays.asList(5)
)

List<Integer> flattened = new ArrayList<>();

for (List<Integer> integerList : integerLists) {
    flattened.addAll(integerList);
}

for (Integer i : flattened) {
    System.out.println(i);
}

Commenting out code blocks in Atom

On an belgium keyboard asserted on the mac command + shift + / is the keystroke for commenting out a block.

How do I do logging in C# without using 3rd party libraries?

If you want to stay close to .NET check out Enterprise Library Logging Application Block. Look here. Or for a quickstart tutorial check this. I have used the Validation application Block from the Enterprise Library and it really suits my needs and is very easy to "inherit" (install it and refrence it!) in your project.

Javascript: Uncaught TypeError: Cannot call method 'addEventListener' of null

Move script tag at the end of BODY instead of HEAD because in current code when the script is computed html element doesn't exist in document.

Since you don't want to you jquery. Use window.onload or document.onload to execute the entire piece of code that you have in current script tag. window.onload vs document.onload

Extract the first word of a string in a SQL Server query

A slight tweak to the function returns the next word from a start point in the entry

    CREATE FUNCTION [dbo].[GetWord] 
    (
        @value varchar(max)
        , @startLocation int
    ) 
    RETURNS varchar(max) 
    AS 
      BEGIN 

         SET @value = LTRIM(RTRIM(@Value))  
         SELECT @startLocation = 
                CASE 
                    WHEN @startLocation > Len(@value) THEN LEN(@value) 
                    ELSE @startLocation 
                END

            SELECT @value = 
                CASE 
                    WHEN @startLocation > 1 
                        THEN LTRIM(RTRIM(RIGHT(@value, LEN(@value) - @startLocation)))
                    ELSE @value
                END

            RETURN CASE CHARINDEX(' ', @value, 1) 
                    WHEN 0 THEN @value 
                    ELSE SUBSTRING(@value, 1, CHARINDEX(' ', @value, 1) - 1) 
                END

     END 
    GO

    SELECT dbo.GetWord(NULL, 1) 
    SELECT dbo.GetWord('', 1) 
    SELECT dbo.GetWord('abc', 1) 
    SELECT dbo.GetWord('abc def', 4) 
    SELECT dbo.GetWord('abc def ghi', 20) 

Connecting to smtp.gmail.com via command line

This is command for connect

  • server_name: smtp.gmail.com
  • server_port: 587
  • user_name__hash: echo -n '{{user_name}}' | base64
  • user_password__hash: echo -n '{{user_password}}' | base64
openssl s_client -connect {{server_name}}:{{server_port}} -crlf -quiet -starttls smtp

and steps to accept message to send

auth login
{{user_name__hash}}
{{user_password__hash}}
helo {{server_name}}
mail from: <{{message_from}}>
rcpt to: <{{message_to}}>
DATA
from: <{{message_from}}>
to: <{{message_to}}>
subject:{{message_subject}}
Content-Type: text/html; charset='UTF-8'; Content-Transfer-Encoding: base64;
MIME-Version: 1.0
{{message_content}}
.
quit

"google is not defined" when using Google Maps V3 in Firefox remotely

I think the easiest trick is:

<script src="https://maps.googleapis.com/maps/api/js?key=YOUR API KEY&callback=initMap">google.maps.event.addDomListener(window,'load', initMap);</script>

It will init the map when your app is ready.

Check this.

How do you get git to always pull from a specific branch?

Under [branch "master"], try adding the following to the repo's Git config file (.git/config):

[branch "master"]
    remote = origin
    merge = refs/heads/master

This tells Git 2 things:

  1. When you're on the master branch, the default remote is origin.
  2. When using git pull on the master branch, with no remote and branch specified, use the default remote (origin) and merge in the changes from the remote master branch.

I'm not sure why this setup would've been removed from your configuration, though. You may have to follow the suggestions that other people have posted, too, but this may work (or help at least).

If you don't want to edit the config file by hand, you can use the command-line tool instead:

$ git config branch.master.remote origin
$ git config branch.master.merge refs/heads/master

What is the meaning of {...this.props} in Reactjs

It's ES6 Spread_operator and Destructuring_assignment.

<div {...this.props}>
  Content Here
</div>

It's equal to Class Component

const person = {
    name: "xgqfrms",
    age: 23,
    country: "China"
};

class TestDemo extends React.Component {
    render() {
        const {name, age, country} = {...this.props};
        // const {name, age, country} = this.props;
        return (
          <div>
              <h3> Person Information: </h3>
              <ul>
                <li>name={name}</li>
                <li>age={age}</li>
                <li>country={country}</li>
              </ul>
          </div>
        );
    }
}

ReactDOM.render(
    <TestDemo {...person}/>
    , mountNode
);

enter image description here


or Function component

const props = {
    name: "xgqfrms",
    age: 23,
    country: "China"
};

const Test = (props) => {
  return(
    <div
        name={props.name}
        age={props.age}
        country={props.country}>
        Content Here
        <ul>
          <li>name={props.name}</li>
          <li>age={props.age}</li>
          <li>country={props.country}</li>
        </ul>
    </div>
  );
};

ReactDOM.render(
    <div>
        <Test {...props}/>
        <hr/>
        <Test 
            name={props.name}
            age={props.age}
            country={props.country}
        />
    </div>
    , mountNode
);

enter image description here

refs

Laravel Eloquent: How to get only certain columns from joined tables

If I good understood this what is returned is fine except you want to see only one column. If so this below should be much simpler:

return Response::eloquent(Theme::with('user')->get(['username']));

Automatically start a Windows Service on install

After refactoring a little bit, this is an example of a complete windows service installer with automatic start:

using System.ComponentModel;
using System.Configuration.Install;
using System.ServiceProcess;

namespace Example.of.name.space
{
[RunInstaller(true)]
public partial class ServiceInstaller : Installer
{
    private readonly ServiceProcessInstaller processInstaller;
    private readonly System.ServiceProcess.ServiceInstaller serviceInstaller;

    public ServiceInstaller()
    {
        InitializeComponent();
        processInstaller = new ServiceProcessInstaller();
        serviceInstaller = new System.ServiceProcess.ServiceInstaller();

        // Service will run under system account
        processInstaller.Account = ServiceAccount.LocalSystem;

        // Service will have Automatic Start Type
        serviceInstaller.StartType = ServiceStartMode.Automatic;

        serviceInstaller.ServiceName = "Windows Automatic Start Service";

        Installers.Add(serviceInstaller);
        Installers.Add(processInstaller);
        serviceInstaller.AfterInstall += ServiceInstaller_AfterInstall;            
    }
    private void ServiceInstaller_AfterInstall(object sender, InstallEventArgs e)
    {
        ServiceController sc = new ServiceController("Windows Automatic Start Service");
        sc.Start();
    }
}
}

Key error when selecting columns in pandas dataframe after read_csv

The key error generally comes if the key doesn't match any of the dataframe column name 'exactly':

You could also try:

import csv
import pandas as pd
import re
    with open (filename, "r") as file:
        df = pd.read_csv(file, delimiter = ",")
        df.columns = ((df.columns.str).replace("^ ","")).str.replace(" $","")
        print(df.columns)

android.app.Application cannot be cast to android.app.Activity

In my case, when I'm in an activity that extends from AppCompatActivity, it did not work(Activity) getApplicationContext (), I just putthis in its place.

iPhone - Get Position of UIView within entire UIWindow

In Swift:

let globalPoint = aView.superview?.convertPoint(aView.frame.origin, toView: nil)

Get current NSDate in timestamp format

It's convenient to define a macro for get current timestamp

class Constant {
    struct Time {
        let now = { round(NSDate().timeIntervalSince1970) } // seconds
    }
} 

Then you can use let timestamp = Constant.Time.now()

CSS float right not working correctly

LIke this

final answer

css

h2 {
    border-bottom-width: 1px;
    border-bottom-style: solid;
    margin: 0;
    padding: 0;
}
.edit_button {
    float: right;
}

demo1

css

h2 {
    border-bottom-width: 1px;
    border-bottom-style: solid;
    border-bottom-color: gray;
    float: left;
    margin: 0;
    padding: 0;
}
.edit_button {
    float: right;
}

html

<h2>
Contact Details</h2>
<button type="button" class="edit_button" >My Button</button>

demo

html

<div style="border-bottom-width: 1px; border-bottom-style: solid; border-bottom-color: gray; float:left;">
Contact Details



</div>
<button type="button" class="edit_button" style="float: right;">My Button</button>

How to convert a string to number in TypeScript?

There are inbuilt functions like parseInt(), parseFloat() and Number() in Typescript, you can use those.

How do I check OS with a preprocessor directive?

Some compilers will generate #defines that can help you with this. Read the compiler documentation to determine what they are. MSVC defines one that's __WIN32__, GCC has some you can see with touch foo.h; gcc -dM foo.h

What are C++ functors and their uses?

A functor is a higher-order function that applies a function to the parametrized(ie templated) types. It is a generalization of the map higher-order function. For example, we could define a functor for std::vector like this:

template<class F, class T, class U=decltype(std::declval<F>()(std::declval<T>()))>
std::vector<U> fmap(F f, const std::vector<T>& vec)
{
    std::vector<U> result;
    std::transform(vec.begin(), vec.end(), std::back_inserter(result), f);
    return result;
}

This function takes a std::vector<T> and returns std::vector<U> when given a function F that takes a T and returns a U. A functor doesn't have to be defined over container types, it can be defined for any templated type as well, including std::shared_ptr:

template<class F, class T, class U=decltype(std::declval<F>()(std::declval<T>()))>
std::shared_ptr<U> fmap(F f, const std::shared_ptr<T>& p)
{
    if (p == nullptr) return nullptr;
    else return std::shared_ptr<U>(new U(f(*p)));
}

Heres a simple example that converts the type to a double:

double to_double(int x)
{
    return x;
}

std::shared_ptr<int> i(new int(3));
std::shared_ptr<double> d = fmap(to_double, i);

std::vector<int> is = { 1, 2, 3 };
std::vector<double> ds = fmap(to_double, is);

There are two laws that functors should follow. The first is the identity law, which states that if the functor is given an identity function, it should be the same as applying the identity function to the type, that is fmap(identity, x) should be the same as identity(x):

struct identity_f
{
    template<class T>
    T operator()(T x) const
    {
        return x;
    }
};
identity_f identity = {};

std::vector<int> is = { 1, 2, 3 };
// These two statements should be equivalent.
// is1 should equal is2
std::vector<int> is1 = fmap(identity, is);
std::vector<int> is2 = identity(is);

The next law is the composition law, which states that if the functor is given a composition of two functions, it should be the same as applying the functor for the first function and then again for the second function. So, fmap(std::bind(f, std::bind(g, _1)), x) should be the same as fmap(f, fmap(g, x)):

double to_double(int x)
{
    return x;
}

struct foo
{
    double x;
};

foo to_foo(double x)
{
    foo r;
    r.x = x;
    return r;
}

std::vector<int> is = { 1, 2, 3 };
// These two statements should be equivalent.
// is1 should equal is2
std::vector<foo> is1 = fmap(std::bind(to_foo, std::bind(to_double, _1)), is);
std::vector<foo> is2 = fmap(to_foo, fmap(to_double, is));

How to instantiate a File object in JavaScript?

The idea ...To create a File object (api) in javaScript for images already present in the DOM :

<img src="../img/Products/fijRKjhudDjiokDhg1524164151.jpg">

var file = new File(['fijRKjhudDjiokDhg1524164151'],
                     '../img/Products/fijRKjhudDjiokDhg1524164151.jpg', 
                     {type:'image/jpg'});

// created object file
console.log(file);

Don't do that ! ... (but I did it anyway)

-> the console give a result similar as an Object File :

File(0) {name: "fijRKjokDhgfsKtG1527053050.jpg", lastModified: 1527053530715, lastModifiedDate: Wed May 23 2018 07:32:10 GMT+0200 (Paris, Madrid (heure d’été)), webkitRelativePath: "", size: 0, …}
lastModified:1527053530715
lastModifiedDate:Wed May 23 2018 07:32:10 GMT+0200 (Paris, Madrid (heure d’été)) {}
name:"fijRKjokDhgfsKtG1527053050.jpg"
size:0
type:"image/jpg"
webkitRelativePath:""__proto__:File

But the size of the object is wrong ...

Why i need to do that ?

For example to retransmit an image form already uploaded, during a product update, along with additional images added during the update

How to add lines to end of file on Linux

The easiest way is to redirect the output of the echo by >>:

echo 'VNCSERVERS="1:root"' >> /etc/sysconfig/configfile
echo 'VNCSERVERARGS[1]="-geometry 1600x1200"' >> /etc/sysconfig/configfile

How does String substring work in Swift

Swift 5 Extension:

extension String {
    subscript(_ range: CountableRange<Int>) -> String {
        let start = index(startIndex, offsetBy: max(0, range.lowerBound))
        let end = index(start, offsetBy: min(self.count - range.lowerBound, 
                                             range.upperBound - range.lowerBound))
        return String(self[start..<end])
    }

    subscript(_ range: CountablePartialRangeFrom<Int>) -> String {
        let start = index(startIndex, offsetBy: max(0, range.lowerBound))
         return String(self[start...])
    }
}

Usage:

let s = "hello"
s[0..<3] // "hel"
s[3...]  // "lo"

Or unicode:

let s = ""
s[0..<1] // ""

Creating a new ArrayList in Java

You're very close. Use same type on both sides, and include ().

ArrayList<Class> myArray = new ArrayList<Class>();

No @XmlRootElement generated by JAXB

Joe's answer (Joe Jun 26 '09 at 17:26) does it for me. The simple answer is that absence of an @XmlRootElement annotation is no problem if you marshal a JAXBElement. The thing that confused me is the generated ObjectFactory has 2 createMyRootElement methods - the first takes no parameters and gives the unwrapped object, the second takes the unwrapped object and returns it wrapped in a JAXBElement, and marshalling that JAXBElement works fine. Here's the basic code I used (I'm new to this, so apologies if the code's not formatted correctly in this reply), largely cribbed from link text:

ObjectFactory objFactory = new ObjectFactory();
MyRootElement root = objFactory.createMyRootElement();
...
// Set root properties
...
if (!writeDocument(objFactory.createMyRootElement(root), output)) {
    System.err.println("Failed to marshal XML document");
}
...

private boolean writeDocument(JAXBElement document, OutputStream output) {

  Class<?> clazz = document.getValue().getClass();
  try {
    JAXBContext context =
        JAXBContext.newInstance(clazz.getPackage().getName());
    Marshaller m = context.createMarshaller();
    m.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, Boolean.TRUE);
    m.marshal(document, output);
    return true;

  } catch (JAXBException e) {
    e.printStackTrace(System.err);
    return false;
  }
}

JavaScript string and number conversion

To convert a string to a number, subtract 0. To convert a number to a string, add "" (the empty string).

5 + 1 will give you 6

(5 + "") + 1 will give you "51"

("5" - 0) + 1 will give you 6

Is it possible to install iOS 6 SDK on Xcode 5?

I downloaded XCode 4 and took iOS 6.1 SDK from it to the XCode 5 as described in other answers. Then I also installed iOS 6.1 Simulator (it was available in preferences). I also switched Base SDK to iOS 6.1 in project settings.

After all these manipulations the project with 6.1 base sdk runs in comp ability mode in iOS 7 Simulator.

Is there a "standard" format for command line/shell help text?

Typically, your help output should include:

  • Description of what the app does
  • Usage syntax, which:
    • Uses [options] to indicate where the options go
    • arg_name for a required, singular arg
    • [arg_name] for an optional, singular arg
    • arg_name... for a required arg of which there can be many (this is rare)
    • [arg_name...] for an arg for which any number can be supplied
    • note that arg_name should be a descriptive, short name, in lower, snake case
  • A nicely-formatted list of options, each:
    • having a short description
    • showing the default value, if there is one
    • showing the possible values, if that applies
    • Note that if an option can accept a short form (e.g. -l) or a long form (e.g. --list), include them together on the same line, as their descriptions will be the same
  • Brief indicator of the location of config files or environment variables that might be the source of command line arguments, e.g. GREP_OPTS
  • If there is a man page, indicate as such, otherwise, a brief indicator of where more detailed help can be found

Note further that it's good form to accept both -h and --help to trigger this message and that you should show this message if the user messes up the command-line syntax, e.g. omits a required argument.

1067 error on attempt to start MySQL

...an old one... anyway I had the same issue with MariaDB

In my case most pathes contain special characters like: # Wrapping pathes in my.ini in double quotes made the trick - e.g.

datadir="C:/#windata64/db/MariaDB/data"

C++, How to determine if a Windows Process is running?

#include <cstdio>
#include <windows.h>
#include <tlhelp32.h>

/*!
\brief Check if a process is running
\param [in] processName Name of process to check if is running
\returns \c True if the process is running, or \c False if the process is not running
*/
bool IsProcessRunning(const wchar_t *processName)
{
    bool exists = false;
    PROCESSENTRY32 entry;
    entry.dwSize = sizeof(PROCESSENTRY32);

    HANDLE snapshot = CreateToolhelp32Snapshot(TH32CS_SNAPPROCESS, NULL);

    if (Process32First(snapshot, &entry))
        while (Process32Next(snapshot, &entry))
            if (!wcsicmp(entry.szExeFile, processName))
                exists = true;

    CloseHandle(snapshot);
    return exists;
}

nodejs module.js:340 error: cannot find module

  1. Try npm start in Node.js Command Prompt.
  2. Look at the end of the messages - it gives you the path of log file in "Additional Logging Details ..." something like c:\users\MyUser\npm-debug.log
  3. Open this file in Notepad and find the real address of Node.exe : something like C:\\Program Files\\nodejs\\\\node.exe
  4. Try cd to this path
  5. Call node.exe + <full path to your server file.js>

    Server is listening on port 1337 !
    

Latest jQuery version on Google's CDN

If you wish to use jQuery CDN other than Google hosted jQuery library, you might consider using this and ensures uses the latest version of jQuery:

<script src="http://code.jquery.com/jquery-latest.min.js" type="text/javascript"></script>

Using "&times" word in html changes to ×

&times; stands for × in html. Use &amp;times to get &times

How to get the first five character of a String

You can use Substring(int startIndex, int length)

string result = str.Substring(0,5);

The substring starts at a specified character position and has a specified length. This method does not modify the value of the current instance. Instead, it returns a new string with length characters starting from the startIndex position in the current string, MSDN

What if the source string is less then five characters? You will get exception by using above method. We can put condition to check if the number of characters in string are more then 5 then get first five through Substring. Note I have assigned source string to firstFiveChar variable. The firstFiveChar not change if characters are less then 5, so else part is not required.

string firstFiveChar = str;
If(!String.IsNullOrWhiteSpace(yourStringVariable) && yourStringVariable.Length >= 5)
      firstFiveChar = yourStringVariable.Substring(0, 5);

Getting current unixtimestamp using Moment.js

Try any of these

valof = moment().valueOf();            // xxxxxxxxxxxxx
getTime = moment().toDate().getTime(); // xxxxxxxxxxxxx
unixTime =  moment().unix();           // xxxxxxxxxx
formatTimex =  moment().format('x');   // xxxxxxxxxx
unixFormatX = moment().format('X');    // xxxxxxxxxx

How to build and fill pandas dataframe from for loop?

I may be wrong, but I think the accepted answer by @amit has a bug.

from pandas import DataFrame as df
x = [1,2,3]
y = [7,8,9,10]

# this gives me a syntax error at 'for' (Python 3.7)
d1 = df[[a, "A", b, "B"] for a in x for b in y]

# this works
d2 = df([a, "A", b, "B"] for a in x for b in y)

# and if you want to add the column names on the fly
# note the additional parentheses
d3 = df(([a, "A", b, "B"] for a in x for b in y), columns = ("l","m","n","o"))

What is the best Java QR code generator library?

QRGen is a good library that creates a layer on top of ZXing and makes QR Code generation in Java a piece of cake.

How to unzip gz file using Python

It is very simple.. Here you go !!

import gzip

#path_to_file_to_be_extracted

ip = sample.gzip

#output file to be filled

op = open("output_file","w") 

with gzip.open(ip,"rb") as ip_byte:
    op.write(ip_byte.read().decode("utf-8")
    wf.close()

How to display 3 buttons on the same line in css

Do something like this,

HTML :

<div style="width:500px;">
    <button type="submit" class="msgBtn" onClick="return false;" >Save</button>
    <button type="submit" class="msgBtn2" onClick="return false;">Publish</button>
    <button class="msgBtnBack">Back</button>
</div>

CSS :

div button{
    display:inline-block;
}

Fiddle Demo

Or

HTML :

<div style="width:500px;" id="container">
    <div><button type="submit" class="msgBtn" onClick="return false;" >Save</button></div>
    <div><button type="submit" class="msgBtn2" onClick="return false;">Publish</button></div>
    <div><button class="msgBtnBack">Back</button></div>
</div>

CSS :

#container div{
    display:inline-block;
    width:130px;
}

Fiddle Demo

Color different parts of a RichTextBox string

This is the modified version that I put in my code (I'm using .Net 4.5) but I think it should work on 4.0 too.

public void AppendText(string text, Color color, bool addNewLine = false)
{
        box.SuspendLayout();
        box.SelectionColor = color;
        box.AppendText(addNewLine
            ? $"{text}{Environment.NewLine}"
            : text);
        box.ScrollToCaret();
        box.ResumeLayout();
}

Differences with original one:

  • possibility to add text to a new line or simply append it
  • no need to change selection, it works the same
  • inserted ScrollToCaret to force autoscroll
  • added suspend/resume layout calls

Search for a particular string in Oracle clob column

You can use the way like @Florin Ghita has suggested. But remember dbms_lob.substr has a limit of 4000 characters in the function For example :

dbms_lob.substr(clob_value_column,4000,1)

Otherwise you will find ORA-22835 (buffer too small)

You can also use the other sql way :

SELECT * FROM   your_table WHERE  clob_value_column LIKE '%your string%';

Note : There are performance problems associated with both the above ways like causing Full Table Scans, so please consider about Oracle Text Indexes as well:

https://docs.oracle.com/en/database/oracle/oracle-database/12.2/ccapp/indexing-with-oracle-text.html

Environment variables in Mac OS X

Synchronize OS X environment variables for command line and GUI applications from a single source with osx-env-sync.

I also posted an answer to a related question here.

How to add image in Flutter

How to include images in your app

1. Create an assets/images folder

  • This should be located in the root of your project, in the same folder as your pubspec.yaml file.
  • In Android Studio you can right click in the Project view
  • You don't have to call it assets or images. You don't even need to make images a subfolder. Whatever name you use, though, is what you will regester in the pubspec.yaml file.

2. Add your image to the new folder

  • You can just copy your image into assets/images. The relative path of lake.jpg, for example, would be assets/images/lake.jpg.

3. Register the assets folder in pubspec.yaml

  • Open the pubspec.yaml file that is in the root of your project.

  • Add an assets subsection to the flutter section like this:

      flutter:
        assets:
          - assets/images/lake.jpg
    
  • If you have multiple images that you want to include then you can leave off the file name and just use the directory name (include the final /):

      flutter:
        assets:
          - assets/images/
    

4. Use the image in code

  • Get the asset in an Image widget with Image.asset('assets/images/lake.jpg').

  • The entire main.dart file is here:

      import 'package:flutter/material.dart';
    
      void main() => runApp(MyApp());
    
      class MyApp extends StatelessWidget {
        @override
        Widget build(BuildContext context) {
          return MaterialApp(
            home: Scaffold(
              appBar: AppBar(
                title: Text("Image from assets"),
              ),
              body: Image.asset('assets/images/lake.jpg'), //   <--- image
            ),
          );
        }
      }
    

5. Restart your app

When making changes to pubspec.yaml I find that I often need to completely stop my app and restart it again, especially when adding assets. Otherwise I get a crash.

Running the app now you should have something like this:

enter image description here

Further reading

  • See the documentation for how to do things like provide alternate images for different densities.

Videos

The first video here goes into a lot of detail about how to include images in your app. The second video covers more about how to adjust how they look.

How to get DateTime.Now() in YYYY-MM-DDThh:mm:ssTZD format using C#

Use the zzz format specifier to get the timezone offset as hours and minutes. You also want to use the HH format specifier to get the hours in 24 hour format.

DateTime.Now.ToString("yyyy-MM-ddTHH:mm:sszzz")

Result:

2011-08-09T23:49:58+02:00

Some culture settings uses periods instead of colons for time, so you might want to use literal colons instead of time separators:

DateTime.Now.ToString("yyyy-MM-ddTHH':'mm':'sszzz")

Custom Date and Time Format Strings

Best practice for Django project working directory structure

Here is what I follow on My system.

  1. All Projects: There is a projects directory in my home folder i.e. ~/projects. All the projects rest inside it.

  2. Individual Project: I follow a standardized structure template used by many developers called django-skel for individual projects. It basically takes care of all your static file and media files and all.

  3. Virtual environment: I have a virtualenvs folder inside my home to store all virtual environments in the system i.e. ~/virtualenvs . This gives me flexibility that I know what all virtual environments I have and can look use easily

The above 3 are the main partitions of My working environment.

All the other parts you mentioned are mostly dependent on project to project basis (i.e. you might use different databases for different projects). So they should reside in their individual projects.

How to remove an id attribute from a div using jQuery?

The capitalization is wrong, and you have an extra argument.

Do this instead:

$('img#thumb').removeAttr('id');

For future reference, there aren't any jQuery methods that begin with a capital letter. They all take the same form as this one, starting with a lower case, and the first letter of each joined "word" is upper case.

Dynamically create checkbox with JQuery from text input

Put a global variable to generate the ids.

<script>
    $(function(){
        // Variable to get ids for the checkboxes
        var idCounter=1;
        $("#btn1").click(function(){
            var val = $("#txtAdd").val();
            $("#divContainer").append ( "<label for='chk_" + idCounter + "'>" + val + "</label><input id='chk_" + idCounter + "' type='checkbox' value='" + val + "' />" );
            idCounter ++;
        });
    });
</script>
<div id='divContainer'></div>
<input type="text" id="txtAdd" /> 
<button id="btn1">Click</button>

Disabling Strict Standards in PHP 5.4

It worked for me, when I set error_reporting in two places at same time

somewhere in PHP code

ini_set('error_reporting', 30711);


and in .htaccess file

php_value error_reporting 30711

Unable to resolve "unable to get local issuer certificate" using git on Windows with self-signed certificate

Use this command before to run composer update/install:

git config --global http.sslverify false

How to terminate a thread when main program ends?

If you spawn a Thread like so - myThread = Thread(target = function) - and then do myThread.start(); myThread.join(). When CTRL-C is initiated, the main thread doesn't exit because it is waiting on that blocking myThread.join() call. To fix this, simply put in a timeout on the .join() call. The timeout can be as long as you wish. If you want it to wait indefinitely, just put in a really long timeout, like 99999. It's also good practice to do myThread.daemon = True so all the threads exit when the main thread(non-daemon) exits.

Difference Between Schema / Database in MySQL

Refering to MySql documentation,

CREATE DATABASE creates a database with the given name. To use this statement, you need the CREATE privilege for the database. CREATE SCHEMA is a synonym for CREATE DATABASE as of MySQL 5.0.2.

How can I validate google reCAPTCHA v2 using javascript/jQuery?

Source Link

enter image description here

You can simply check on client side using grecaptcha.getResponse() method

          var rcres = grecaptcha.getResponse();
          if(rcres.length){
            grecaptcha.reset();
            showHideMsg("Form Submitted!","success");
          }else{
            showHideMsg("Please verify reCAPTCHA","error");
          }

MySQL: can't access root account

I got the same problem when accessing mysql with root. The problem I found is that some database files does not have permission by the mysql user, which is the user that started the mysql server daemon.

We can check this with ls -l /var/lib/mysql command, if the mysql user does not have permission of reading or writing on some files or directories, that might cause problem. We can change the owner or mode of those files or directories with chown/chmod commands.

After these changes, restart the mysqld daemon and login with root with command:

mysql -u root

Then change passwords or create other users for logging into mysql.

HTH

Port 443 in use by "Unable to open process" with PID 4

Similarly, I experienced this: Port 443 in use by "Unable to open process" with PID 6012! When starting XAMPP Control Panel v3.2.1 for the first time.

In Task Manager I found that PID 6012 was Apache web server. A copy of it was running in the background without the GUI, and when I invoked the GUI it was trying to start another copy. Killed the phantom copy and then XAMPP started up fine.

I didn't have to change any port settings.

setting request headers in selenium

check this out: chrome_options = Options()

chrome_options.add_argument('--headless')
chrome_options.add_argument('user-agent="Mozilla/5.0 (Macintosh; Intel Mac OS X 10_14_4) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/73.0.3683.103 Safari/537.36"')

Problem solved!

Wampserver icon not going green fully, mysql services not starting up?

You may want to reset data from MySQL

  • delete previous data from C:\wamp\bin\mysql\mysql5.6.17\data
  • restart service

Why is NULL undeclared?

NULL is not a built-in constant in the C or C++ languages. In fact, in C++ it's more or less obsolete, just use a plain literal 0 instead, the compiler will do the right thing depending on the context.

In newer C++ (C++11 and higher), use nullptr (as pointed out in a comment, thanks).

Otherwise, add

#include <stddef.h>

to get the NULL definition.

JQUERY: Uncaught Error: Syntax error, unrecognized expression

Try this (ES5)

console.log($("#" +  d));

ES6

console.log($(`#${d}`));

Servlet returns "HTTP Status 404 The requested resource (/servlet) is not available"

Do the following two steps. I hope, it will solve the "404 not found" issue in tomcat server during the development of java servlet application.

Step 1: Right click on the server(in the server explorer tab)->Properties->Switch Location from workspace metadata to tomcat server

Step 2: Double Click on the server(in the server explorer tab)->Select Use tomcat installation option inside server location menu

Swift: Reload a View Controller

You shouldn't call viewDidLoad method manually, Instead if you want to reload any data or any UI, you can use this:

override func viewDidLoad() {
    super.viewDidLoad();

    let myButton = UIButton()

    // When user touch myButton, we're going to call loadData method
    myButton.addTarget(self, action: #selector(self.loadData), forControlEvents: .TouchUpInside)

    // Load the data
    self.loadData();
}

func loadData() {
    // code to load data from network, and refresh the interface
    tableView.reloadData()
}

Whenever you want to reload the data and refresh the interface, you can call self.loadData()

How does internationalization work in JavaScript?

Some of it is native, the rest is available through libraries.

For example Datejs is a good international date library.

For the rest, it's just about language translation, and JavaScript is natively Unicode compatible (as well as all major browsers).

Converting byte array to String (Java)

public class Main {

    /**
     * Example method for converting a byte to a String.
     */
    public void convertByteToString() {

        byte b = 65;

        //Using the static toString method of the Byte class
        System.out.println(Byte.toString(b));

        //Using simple concatenation with an empty String
        System.out.println(b + "");

        //Creating a byte array and passing it to the String constructor
        System.out.println(new String(new byte[] {b}));

    }

    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        new Main().convertByteToString();
    }
}

Output

65
65
A

How I can delete in VIM all text from current line to end of file?

Go to the first line from which you would like to delete, and press the keys dG

MySql Query Replace NULL with Empty String in Select

Some of these built in functions should work:

Coalesce
Is Null
IfNull

Limit number of characters allowed in form input text field

Use maxlenght="number of charcters"

<input type="text" id="sessionNo" name="sessionNum" maxlenght="7" />

Convert ascii value to char

To convert an int ASCII value to character you can also use:

int asciiValue = 65;
char character = char(asciiValue);
cout << character; // output: A
cout << char(90); // output: Z

PHP: maximum execution time when importing .SQL data file

Simply set $cfg['ExecTimeLimit'] = 0; In xampp/phpMyAdmin/libraries/config.default.php.

Maximum execution time in seconds (0 for no limit).

And make this below changes in php.ini file as per file size.

post_max_size = 600M 
upload_max_filesize = 500M 
max_execution_time = 5000 
max_input_time = 5000 
memory_limit = 600M

But make sure 'post_max_size' and 'memory_limit' should be more than upload_max_filesize.

**Note - Don't forget to restart your server.

Difference between getAttribute() and getParameter()

-getParameter() :

<html>
<body>
<form name="testForm" method="post" action="testJSP.jsp">
<input type="text" name="testParam" value="ClientParam">
<input type="submit">
</form>
</body>
</html>

    <html>
    <body>
    <%
    String sValue = request.getParameter("testParam");
    %>
    <%= sValue %>
    </body>
    </html>

request.getParameter("testParam") will get the value from the posted form of the input box named "testParam" which is "Client param". It will then print it out, so you should see "Client Param" on the screen. So request.getParameter() will retrieve a value that the client has submitted. You will get the value on the server side.

-getAttribute() : request.getAttribute(), this is all done server side. YOU add the attribute to the request and YOU submit the request to another resource, the client does not know about this. So all the code handling this would typically be in servlets.getAttribute always return object.

Jquery function BEFORE form submission

Aghhh... i was missing some code when i first tried the .submit function.....

This works:

$('#create-card-process.design').submit(function() {
    var textStyleCSS = $("#cover-text").attr('style');
    var textbackgroundCSS = $("#cover-text-wrapper").attr('style');
    $("#cover_text_css").val(textStyleCSS);
    $("#cover_text_background_css").val(textbackgroundCSS);
});

Thanks for all the comments.

Converting HTML files to PDF

You can use a headless firefox with an extension. It's pretty annoying to get running but it does produce good results.

Check out this answer for more info.

Equivalent of waitForVisible/waitForElementPresent in Selenium WebDriver tests using Java?

For individual element the code below could be used:

private boolean isElementPresent(By by) {
        try {
            driver.findElement(by);
            return true;
        } catch (NoSuchElementException e) {
            return false;
        }
    }
for (int second = 0;; second++) {
            if (second >= 60){
                fail("timeout");
            }
            try {
                if (isElementPresent(By.id("someid"))){
                    break;
                }
                }
            catch (Exception e) {

            }
            Thread.sleep(1000);
        }

Check if value exists in dataTable?

you could set the database as IEnumberable and use linq to check if the values exist. check out this link

LINQ Query on Datatable to check if record exists

the example given is

var dataRowQuery= myDataTable.AsEnumerable().Where(row => ...

you could supplement where with any

Default visibility for C# classes and members (fields, methods, etc.)?

By default, the access modifier for a class is internal. That means to say, a class is accessible within the same assembly. But if we want the class to be accessed from other assemblies then it has to be made public.

How do I request a file but not save it with Wget?

You can use -O- (uppercase o) to redirect content to the stdout (standard output) or to a file (even special files like /dev/null /dev/stderr /dev/stdout )

wget -O- http://yourdomain.com

Or:

wget -O- http://yourdomain.com > /dev/null

Or: (same result as last command)

wget -O/dev/null http://yourdomain.com

Sending data back to the Main Activity in Android

Another way of achieving the desired result which may be better depending on your situation is to create a listener interface.

By making the parent activity listen to an interface that get triggered by the child activity while passing the required data as a parameter can create a similar set of circumstance

Comparing arrays in JUnit assertions, concise built-in way?

I know the question is for JUnit4, but if you happen to be stuck at JUnit3, you could create a short utility function like that:

private void assertArrayEquals(Object[] esperado, Object[] real) {
    assertEquals(Arrays.asList(esperado), Arrays.asList(real));     
}

In JUnit3, this is better than directly comparing the arrays, since it will detail exactly which elements are different.

Is there a combination of "LIKE" and "IN" in SQL?

do this

WHERE something + '%' in ('bla', 'foo', 'batz')
OR '%' + something + '%' in ('tra', 'la', 'la')

or

WHERE something + '%' in (select col from table where ....)

Round number to nearest integer

For positives, try

int(x + 0.5)

To make it work for negatives too, try

int(x + (0.5 if x > 0 else -0.5))

int() works like a floor function and hence you can exploit this property. This is definitely the fastest way.

How to parse JSON in Scala using standard Scala classes?

scala.util.parsing.json.JSON is deprecated.

Here is another approach with circe. FYI documentation: https://circe.github.io/circe/cursors.html

Add the dependency in build.sbt, I used scala 2.13.4, note the scala version must align with the library version.

val circeVersion = "0.14.0-M2"

libraryDependencies ++= Seq(
  "io.circe"  %% "circe-core"     % circeVersion,
  "io.circe"  %% "circe-generic"  % circeVersion,
  "io.circe"  %% "circe-parser"   % circeVersion
)

Example 1:

case class Person(name: String, age: Int)

object Main {
  def main(args: Array[String]): Unit = {
    val input =
      """
        |{
        |  "kind": "Listing",
        |  "data": [
        |    {
        |      "name": "Frodo",
        |      "age": 51
        |    },
        |    {
        |      "name": "Bilbo",
        |      "age": 60
        |    }
        |  ]
        |}
        |""".stripMargin

    implicit val decoderPerson: Decoder[Person] = deriveDecoder[Person] // decoder required to parse to custom object

    val parseResult: Json = circe.parser.parse(input).getOrElse(Json.Null)
    val data: ACursor = parseResult.hcursor.downField("data") // get the data field
    val personList: List[Person] = data.as[List[Person]].getOrElse(null) // parse the dataField to a list of Person
    for {
      person <- personList
    } println(person.name + " is " + person.age)
  }
}

Example 2, json has an object within an object:

case class Person(name: String, age: Int, position: Position)
case class Position(x: Int, y: Int)

object Main {
  def main(args: Array[String]): Unit = {
    val input =
      """
        |{
        |  "kind": "Listing",
        |  "data": [
        |    {
        |      "name": "Frodo",
        |      "age": 51,
        |      "position": {
        |        "x": 10,
        |        "y": 20
        |      }
        |    },
        |    {
        |      "name": "Bilbo",
        |      "age": 60,
        |      "position": {
        |        "x": 75,
        |        "y": 85
        |      }
        |    }
        |  ]
        |}
        |""".stripMargin

    implicit val decoderPosition: Decoder[Position] = deriveDecoder[Position] // must be defined before the Person decoder
    implicit val decoderPerson: Decoder[Person] = deriveDecoder[Person]

    val parseResult = circe.parser.parse(input).getOrElse(Json.Null)
    val data = parseResult.hcursor.downField("data")
    val personList = data.as[List[Person]].getOrElse(null)
    for {
      person <- personList
    } println(person.name + " is " + person.age + " at " + person.position)
  }
}

Printing Java Collections Nicely (toString Doesn't Return Pretty Output)

Newer JDK already has AbstractCollection.toString() implemented, and Stack extends AbstractCollection so you just have to call toString() on your collection:

    public abstract class AbstractCollection<E> implements Collection<E> {
    ...
    public String toString() {
        Iterator<E> it = iterator();
        if (! it.hasNext())
            return "[]";
    
        StringBuilder sb = new StringBuilder();
        sb.append('[');
        for (;;) {
            E e = it.next();
            sb.append(e == this ? "(this Collection)" : e);
            if (! it.hasNext())
                return sb.append(']').toString();
            sb.append(',').append(' ');
        }
    }

How to export/import PuTTy sessions list?

Using this method it is also possible to perform mass configuration changes, such as changing the all sessions font.

  1. Export to .reg
  2. Perform a search and replace over .reg
  3. Remove all sessions
  4. Import the new .reg

Extracted from here: http://www.sysadmit.com/2015/11/putty-exportar-configuracion.html

File tree view in Notepad++

You can add it from the notepad++ toolbar Plugins > Plugin Manager > Show Plugin Manager. Then select the Explorer plugin and click the Install button.

Submit Button Image

<INPUT TYPE="image" SRC="images/submit.gif" HEIGHT="30" WIDTH="173" BORDER="0" ALT="Submit Form">
Where the standard submit button has TYPE="submit", we now have TYPE="image". The image type is by default a form submitting button. More simple

How to save a bitmap on internal storage

Modify onClick() as follows:

@Override
public void onClick(View v) {
    if(v == btn) {
        canvas=sv.getHolder().lockCanvas();
        if(canvas!=null) {
            canvas.drawBitmap(bitmap, 100, 100, null);
            sv.getHolder().unlockCanvasAndPost(canvas);
        }
    } else if(v == btn1) {
        saveBitmapToInternalStorage(bitmap);
    }
}

There are several ways to enforce that btn must be pressed before btn1 so that the bitmap is painted before you attempt to save it.

I suggest that you initially disable btn1, and that you enable it when btn is clicked, like this:

if(v == btn) {
    ...
    btn1.setEnabled(true);
}

Convert ASCII TO UTF-8 Encoding

Use mb_convert_encoding to convert an ASCII to UTF-8. More info here

$string = "chárêctërs";
print(mb_detect_encoding ($string));

$string = mb_convert_encoding($string, "UTF-8");
print(mb_detect_encoding ($string));

How can I add a volume to an existing Docker container?

Jérôme Petazzoni has a pretty interesting blog post on how to Attach a volume to a container while it is running. This isn't something that's built into Docker out of the box, but possible to accomplish.

As he also points out

This will not work on filesystems which are not based on block devices.

It will only work if /proc/mounts correctly lists the block device node (which, as we saw above, is not necessarily true).

Also, I only tested this on my local environment; I didn’t even try on a cloud instance or anything like that

YMMV

How to stretch div height to fill parent div - CSS

If you're gonna use B2 for styling purposes you can try this "hack"

#B { overflow: hidden;}
#B2 {padding-bottom: 9999px; margin-bottom: -9999px}

jsFiddle

Bootstrap: adding gaps between divs

The easiest way to do it is to add mb-5 to your classes. That is <div class='row mb-5'>.

NOTE:

  • mb varies betweeen 1 to 5
  • The Div MUST have the row class

How to return string value from the stored procedure

You are placing your result in the RETURN value instead of in the passed @rvalue.

From MSDN

(RETURN) Is the integer value that is returned. Stored procedures can return an integer value to a calling procedure or an application.

Changing your procedure.

ALTER procedure S_Comp(@str1 varchar(20),@r varchar(100) out) as 

    declare @str2 varchar(100) 
    set @str2 ='welcome to sql server. Sql server is a product of Microsoft' 
    if(PATINDEX('%'+@str1 +'%',@str2)>0) 
        SELECT @r =  @str1+' present in the string' 
    else 
        SELECT @r = @str1+' not present'

Calling the procedure

  DECLARE @r VARCHAR(100)
  EXEC S_Comp 'Test', @r OUTPUT
  SELECT @r

JavaScript inside an <img title="<a href='#' onClick='alert('Hello World!')>The Link</a>" /> possible?

Im my browser, this doesn't work at all. The tooltip field doesn't show a link, but <a href='#' onClick='alert('Hello World!')>The Link</a>. I'm using FF 3.6.12.

You'll have to do this by hand with JS and CSS. Begin here

Solving Quadratic Equation

Below is the Program to Solve Quadratic Equation.

For Example: Solve x2 + 3x – 4 = 0

This quadratic happens to factor:

x2 + 3x – 4 = (x + 4)(x – 1) = 0

we already know that the solutions are x = –4 and x = 1.

enter image description here

    # import complex math module
    import cmath

    a = 1
    b = 5
    c = 6

    # To take coefficient input from the users
    # a = float(input('Enter a: '))
    # b = float(input('Enter b: '))
    # c = float(input('Enter c: '))

    # calculate the discriminant
    d = (b**2) - (4*a*c)

    # find two solutions
    sol1 = (-b-cmath.sqrt(d))/(2*a)
    sol2 = (-b+cmath.sqrt(d))/(2*a)

    print('The solution are {0} and {1}'.format(sol1,sol2))

Source: Python Program to Solve Quadratic Equation

SyntaxError: missing ; before statement

Looks like you have an extra parenthesis.

The following portion is parsed as an assignment so the interpreter/compiler will look for a semi-colon or attempt to insert one if certain conditions are met.

foob_name = $this.attr('name').replace(/\[(\d+)\]/, function($0, $1) {
   return '[' + (+$1 + 1) + ']';
})

Dynamically add script tag with src that may include document.write

You can try following code snippet.

function addScript(attribute, text, callback) {
    var s = document.createElement('script');
    for (var attr in attribute) {
        s.setAttribute(attr, attribute[attr] ? attribute[attr] : null)
    }
    s.innerHTML = text;
    s.onload = callback;
    document.body.appendChild(s);
}

addScript({
    src: 'https://www.google.com',
    type: 'text/javascript',
    async: null
}, '<div>innerHTML</div>', function(){});

writing to existing workbook using xlwt

Here's some sample code I used recently to do just that.

It opens a workbook, goes down the rows, if a condition is met it writes some data in the row. Finally it saves the modified file.

from xlutils.copy import copy # http://pypi.python.org/pypi/xlutils
from xlrd import open_workbook # http://pypi.python.org/pypi/xlrd

START_ROW = 297 # 0 based (subtract 1 from excel row number)
col_age_november = 1
col_summer1 = 2
col_fall1 = 3

rb = open_workbook(file_path,formatting_info=True)
r_sheet = rb.sheet_by_index(0) # read only copy to introspect the file
wb = copy(rb) # a writable copy (I can't read values out of this, only write to it)
w_sheet = wb.get_sheet(0) # the sheet to write to within the writable copy

for row_index in range(START_ROW, r_sheet.nrows):
    age_nov = r_sheet.cell(row_index, col_age_november).value
    if age_nov == 3:
        #If 3, then Combo I 3-4 year old  for both summer1 and fall1
        w_sheet.write(row_index, col_summer1, 'Combo I 3-4 year old')
        w_sheet.write(row_index, col_fall1, 'Combo I 3-4 year old')

wb.save(file_path + '.out' + os.path.splitext(file_path)[-1])

How to convert a color integer to a hex String in Android?

If you use Integer.toHexString you will end-up with missed zeros when you convert colors like 0xFF000123. Here is my kotlin based solution which doesn't require neither android specific classes nor java. So you could use it in multiplatform project as well:

    fun Int.toRgbString(): String =
        "#${red.toStringComponent()}${green.toStringComponent()}${blue.toStringComponent()}".toUpperCase()

    fun Int.toArgbString(): String =
        "#${alpha.toStringComponent()}${red.toStringComponent()}${green.toStringComponent()}${blue.toStringComponent()}".toUpperCase()

    private fun Int.toStringComponent(): String =
        this.toString(16).let { if (it.length == 1) "0${it}" else it }

    inline val Int.alpha: Int
        get() = (this shr 24) and 0xFF

    inline val Int.red: Int
        get() = (this shr 16) and 0xFF

    inline val Int.green: Int
        get() = (this shr 8) and 0xFF

    inline val Int.blue: Int
        get() = this and 0xFF

How to tell git to use the correct identity (name and email) for a given project?

You need to use the local set command below:

local set

git config user.email [email protected]
git config user.name 'Mahmoud Zalt'

local get

git config --get user.email
git config --get user.name

The local config file is in the project directory: .git/config.

global set

git config --global user.email [email protected]
git config --global user.name 'Mahmoud Zalt'

global get

git config --global --get user.email
git config --global --get user.name

The global config file in in your home directory: ~/.gitconfig.

Remember to quote blanks, etc, for example: 'FirstName LastName'

I'm getting Key error in python

I fully agree with the Key error comments. You could also use the dictionary's get() method as well to avoid the exceptions. This could also be used to give a default path rather than None as shown below.

>>> d = {"a":1, "b":2}
>>> x = d.get("A",None)
>>> print x
None

Failed to resolve: com.android.support:appcompat-v7:26.0.0

File -> Project Structure -> Modules (app) -> Open Dependencies Tab -> Remove all then use + to add from the proposed list.

Syntax error "syntax error, unexpected end-of-input, expecting keyword_end (SyntaxError)"

$ rails server -b $IP -p $PORT - that solved the same problem for me

sscanf in Python

There is an example in the official python docs about how to use sscanf from libc:

    # import libc
    from ctypes import CDLL
    if(os.name=="nt"):
        libc = cdll.msvcrt 
    else:
        # assuming Unix-like environment
        libc = cdll.LoadLibrary("libc.so.6")
        libc = CDLL("libc.so.6")  # alternative

    # allocate vars
    i = c_int()
    f = c_float()
    s = create_string_buffer(b'\000' * 32)

    # parse with sscanf
    libc.sscanf(b"1 3.14 Hello", "%d %f %s", byref(i), byref(f), s)

    # read the parsed values
    i.value  # 1
    f.value  # 3.14
    s.value # b'Hello'

Array of structs example

Given an instance of the struct, you set the values.

    student thisStudent;
    Console.WriteLine("Please enter StudentId, StudentName, CourseName, Date-Of-Birth");
    thisStudent.s_id = int.Parse(Console.ReadLine());
    thisStudent.s_name = Console.ReadLine();
    thisStudent.c_name = Console.ReadLine();
    thisStudent.s_dob = Console.ReadLine();

Note this code is incredibly fragile, since we aren't checking the input from the user at all. And you aren't clear to the user that you expect each data point to be entered on a separate line.

Break statement in javascript array map method

That's not possible using the built-in Array.prototype.map. However, you could use a simple for-loop instead, if you do not intend to map any values:

var hasValueLessThanTen = false;
for (var i = 0; i < myArray.length; i++) {
  if (myArray[i] < 10) {
    hasValueLessThanTen = true;
    break;
  }
}

Or, as suggested by @RobW, use Array.prototype.some to test if there exists at least one element that is less than 10. It will stop looping when some element that matches your function is found:

var hasValueLessThanTen = myArray.some(function (val) { 
  return val < 10;
});

Laravel - Session store not set on request

A problem can be that you try to access you session inside of your controller's __constructor() function.

From Laravel 5.3+ this is not possible anymore because it is not intended to work anyway, as stated in the upgrade guide.

In previous versions of Laravel, you could access session variables or the authenticated user in your controller's constructor. This was never intended to be an explicit feature of the framework. In Laravel 5.3, you can't access the session or authenticated user in your controller's constructor because the middleware has not run yet.

For more background information also read Taylor his response.

Workaround

If you still want to use this, you can dynamically create a middleware and run it in the constructor, as described in the upgrade guide:

As an alternative, you may define a Closure based middleware directly in your controller's constructor. Before using this feature, make sure that your application is running Laravel 5.3.4 or above:

<?php

namespace App\Http\Controllers;

use App\User;
use Illuminate\Support\Facades\Auth;
use App\Http\Controllers\Controller;

class ProjectController extends Controller
{
    /**
     * All of the current user's projects.
     */
    protected $projects;

    /**
     * Create a new controller instance.
     *
     * @return void
     */
    public function __construct()
    {
        $this->middleware(function ($request, $next) {
            $this->projects = Auth::user()->projects;

            return $next($request);
        });
    }
}

Why does Date.parse give incorrect results?

During recent experience writing a JS interpreter I wrestled plenty with the inner workings of ECMA/JS dates. So, I figure I'll throw in my 2 cents here. Hopefully sharing this stuff will help others with any questions about the differences among browsers in how they handle dates.

The Input Side

All implementations store their date values internally as 64-bit numbers that represent the number of milliseconds (ms) since 1970-01-01 UTC (GMT is the same thing as UTC). This date is the ECMAScript epoch that is also used by other languages such as Java and POSIX systems such as UNIX. Dates occurring after the epoch are positive numbers and dates prior are negative.

The following code is interpreted as the same date in all current browsers, but with the local timezone offset:

Date.parse('1/1/1970'); // 1 January, 1970

In my timezone (EST, which is -05:00), the result is 18000000 because that's how many ms are in 5 hours (it's only 4 hours during daylight savings months). The value will be different in different time zones. This behaviour is specified in ECMA-262 so all browsers do it the same way.

While there is some variance in the input string formats that the major browsers will parse as dates, they essentially interpret them the same as far as time zones and daylight saving is concerned even though parsing is largely implementation dependent.

However, the ISO 8601 format is different. It's one of only two formats outlined in ECMAScript 2015 (ed 6) specifically that must be parsed the same way by all implementations (the other is the format specified for Date.prototype.toString).

But, even for ISO 8601 format strings, some implementations get it wrong. Here is a comparison output of Chrome and Firefox when this answer was originally written for 1/1/1970 (the epoch) on my machine using ISO 8601 format strings that should be parsed to exactly the same value in all implementations:

Date.parse('1970-01-01T00:00:00Z');       // Chrome: 0         FF: 0
Date.parse('1970-01-01T00:00:00-0500');   // Chrome: 18000000  FF: 18000000
Date.parse('1970-01-01T00:00:00');        // Chrome: 0         FF: 18000000
  • In the first case, the "Z" specifier indicates that the input is in UTC time so is not offset from the epoch and the result is 0
  • In the second case, the "-0500" specifier indicates that the input is in GMT-05:00 and both browsers interpret the input as being in the -05:00 timezone. That means that the UTC value is offset from the epoch, which means adding 18000000ms to the date's internal time value.
  • The third case, where there is no specifier, should be treated as local for the host system. FF correctly treats the input as local time while Chrome treats it as UTC, so producing different time values. For me this creates a 5 hour difference in the stored value, which is problematic. Other systems with different offsets will get different results.

This difference has been fixed as of 2020, but other quirks exist between browsers when parsing ISO 8601 format strings.

But it gets worse. A quirk of ECMA-262 is that the ISO 8601 date–only format (YYYY-MM-DD) is required to be parsed as UTC, whereas ISO 8601 requires it to be parsed as local. Here is the output from FF with the long and short ISO date formats with no time zone specifier.

Date.parse('1970-01-01T00:00:00');       // 18000000
Date.parse('1970-01-01');                // 0

So the first is parsed as local because it's ISO 8601 date and time with no timezone, and the second is parsed as UTC because it's ISO 8601 date only.

So, to answer the original question directly, "YYYY-MM-DD" is required by ECMA-262 to be interpreted as UTC, while the other is interpreted as local. That's why:

This doesn't produce equivalent results:

console.log(new Date(Date.parse("Jul 8, 2005")).toString()); // Local
console.log(new Date(Date.parse("2005-07-08")).toString());  // UTC

This does:

console.log(new Date(Date.parse("Jul 8, 2005")).toString());
console.log(new Date(Date.parse("2005-07-08T00:00:00")).toString());

The bottom line is this for parsing date strings. The ONLY ISO 8601 string that you can safely parse across browsers is the long form with an offset (either ±HH:mm or "Z"). If you do that you can safely go back and forth between local and UTC time.

This works across browsers (after IE9):

console.log(new Date(Date.parse("2005-07-08T00:00:00Z")).toString());

Most current browsers do treat the other input formats equally, including the frequently used '1/1/1970' (M/D/YYYY) and '1/1/1970 00:00:00 AM' (M/D/YYYY hh:mm:ss ap) formats. All of the following formats (except the last) are treated as local time input in all browsers. The output of this code is the same in all browsers in my timezone. The last one is treated as -05:00 regardless of the host timezone because the offset is set in the timestamp:

console.log(Date.parse("1/1/1970"));
console.log(Date.parse("1/1/1970 12:00:00 AM"));
console.log(Date.parse("Thu Jan 01 1970"));
console.log(Date.parse("Thu Jan 01 1970 00:00:00"));
console.log(Date.parse("Thu Jan 01 1970 00:00:00 GMT-0500"));

However, since parsing of even the formats specified in ECMA-262 is not consistent, it is recommended to never rely on the built–in parser and to always manually parse strings, say using a library and provide the format to the parser.

E.g. in moment.js you might write:

let m = moment('1/1/1970', 'M/D/YYYY'); 

The Output Side

On the output side, all browsers translate time zones the same way but they handle the string formats differently. Here are the toString functions and what they output. Notice the toUTCString and toISOString functions output 5:00 AM on my machine. Also, the timezone name may be an abbreviation and may be different in different implementations.

Converts from UTC to Local time before printing

 - toString
 - toDateString
 - toTimeString
 - toLocaleString
 - toLocaleDateString
 - toLocaleTimeString

Prints the stored UTC time directly

 - toUTCString
 - toISOString 

In Chrome
toString            Thu Jan 01 1970 00:00:00 GMT-05:00 (Eastern Standard Time)
toDateString        Thu Jan 01 1970
toTimeString        00:00:00 GMT-05:00 (Eastern Standard Time)
toLocaleString      1/1/1970 12:00:00 AM
toLocaleDateString  1/1/1970
toLocaleTimeString  00:00:00 AM

toUTCString         Thu, 01 Jan 1970 05:00:00 GMT
toISOString         1970-01-01T05:00:00.000Z

In Firefox
toString            Thu Jan 01 1970 00:00:00 GMT-05:00 (Eastern Standard Time)
toDateString        Thu Jan 01 1970
toTimeString        00:00:00 GMT-0500 (Eastern Standard Time)
toLocaleString      Thursday, January 01, 1970 12:00:00 AM
toLocaleDateString  Thursday, January 01, 1970
toLocaleTimeString  12:00:00 AM

toUTCString         Thu, 01 Jan 1970 05:00:00 GMT
toISOString         1970-01-01T05:00:00.000Z

I normally don't use the ISO format for string input. The only time that using that format is beneficial to me is when dates need to be sorted as strings. The ISO format is sortable as-is while the others are not. If you have to have cross-browser compatibility, either specify the timezone or use a compatible string format.

The code new Date('12/4/2013').toString() goes through the following internal pseudo-transformation:

  "12/4/2013" -> toUCT -> [storage] -> toLocal -> print "12/4/2013"

I hope this answer was helpful.

Method with a bool return

private bool CheckAll()
{
    if ( ....)
    {
        return true;
    }

    return false;
}

When the if-condition is false the method doesn't know what value should be returned (you probably get an error like "not all paths return a value").

As CQQL pointed out if you mean to return true when your if-condition is true you could have simply written:

private bool CheckAll()
{
    return (your_condition);
}

If you have side effects, and you want to handle them before you return, the first (long) version would be required.

Exception thrown in catch and finally clause

class MyExc1 extends Exception {}
class MyExc2 extends Exception {}
class MyExc3 extends MyExc2 {}

public class C1 {
    public static void main(String[] args) throws Exception {
        try {
            System.out.print("TryA L1\n");
            q();
            System.out.print("TryB L1\n");
        }
        catch (Exception i) {
            System.out.print("Catch L1\n");                
        }
        finally {
            System.out.print("Finally L1\n");
            throw new MyExc1();
        }
    }

    static void q() throws Exception {
        try {
            System.out.print("TryA L2\n");
            q2();
            System.out.print("TryB L2\n");
        }
        catch (Exception y) {
            System.out.print("Catch L2\n");
            throw new MyExc2();  
        }
        finally {
            System.out.print("Finally L2\n");
            throw new Exception();
        }
    }

    static void q2() throws Exception {
        throw new MyExc1();
    }
}

Order:

TryA L1
TryA L2
Catch L2
Finally L2
Catch L1
Finally L1        
Exception in thread "main" MyExc1 at C1.main(C1.java:30)

https://www.compilejava.net/

How to get the entire document HTML as a string?

The correct way is actually:

webBrowser1.DocumentText

Creating temporary files in bash

The mktemp(1) man page explains it fairly well:

Traditionally, many shell scripts take the name of the program with the pid as a suffix and use that as a temporary file name. This kind of naming scheme is predictable and the race condition it creates is easy for an attacker to win. A safer, though still inferior, approach is to make a temporary directory using the same naming scheme. While this does allow one to guarantee that a temporary file will not be subverted, it still allows a simple denial of service attack. For these reasons it is suggested that mktemp be used instead.

In a script, I invoke mktemp something like

mydir=$(mktemp -d "${TMPDIR:-/tmp/}$(basename $0).XXXXXXXXXXXX")

which creates a temporary directory I can work in, and in which I can safely name the actual files something readable and useful.

mktemp is not standard, but it does exist on many platforms. The "X"s will generally get converted into some randomness, and more will probably be more random; however, some systems (busybox ash, for one) limit this randomness more significantly than others


By the way, safe creation of temporary files is important for more than just shell scripting. That's why python has tempfile, perl has File::Temp, ruby has Tempfile, etc…

How can I divide two integers stored in variables in Python?

The 1./2 syntax works because 1. is a float. It's the same as 1.0. The dot isn't a special operator that makes something a float. So, you need to either turn one (or both) of the operands into floats some other way -- for example by using float() on them, or by changing however they were calculated to use floats -- or turn on "true division", by using from __future__ import division at the top of the module.

How to write to a file, using the logging Python module?

here's a simpler way to go about it. this solution doesn't use a config dictionary and uses a rotation file handler, like so:

import logging
from logging.handlers import RotatingFileHandler

logging.basicConfig(handlers=[RotatingFileHandler(filename=logpath+filename,
                     mode='w', maxBytes=512000, backupCount=4)], level=debug_level,
                     format='%(levelname)s %(asctime)s %(message)s', 
                    datefmt='%m/%d/%Y%I:%M:%S %p')

logger = logging.getLogger('my_logger')

or like so:

import logging
from logging.handlers import RotatingFileHandler

handlers = [
            RotatingFileHandler(filename=logpath+filename, mode='w', maxBytes=512000, 
                                backupCount=4)
           ]
logging.basicConfig(handlers=handlers, level=debug_level, 
                    format='%(levelname)s %(asctime)s %(message)s', 
                    datefmt='%m/%d/%Y%I:%M:%S %p')

logger = logging.getLogger('my_logger')

the handlers variable needs to be an iterable. logpath+filename and debug_level are just variables holding the respective info. of course, the values for the function params are up to you.

the first time i was using the logging module i made the mistake of writing the following, which generates an OS file lock error (the above is the solution to that):

import logging
from logging.handlers import RotatingFileHandler

logging.basicConfig(filename=logpath+filename, level=debug_level, format='%(levelname)s %(asctime)s %(message)s', datefmt='%m/%d/%Y
 %I:%M:%S %p')

logger = logging.getLogger('my_logger')
logger.addHandler(RotatingFileHandler(filename=logpath+filename, mode='w', 
                  maxBytes=512000, backupCount=4))

and Bob's your uncle!

delete map[key] in go?

From Effective Go:

To delete a map entry, use the delete built-in function, whose arguments are the map and the key to be deleted. It's safe to do this even if the key is already absent from the map.

delete(timeZone, "PDT")  // Now on Standard Time

What is the difference between MVC and MVVM?

MVC is a controlled environment and MVVM is a reactive environment.

In a controlled environment you should have less code and a common source of logic; which should always live within the controller. However; in the web world MVC easily gets divided into view creation logic and view dynamic logic. Creation lives on the server and dynamic lives on the client. You see this a lot with ASP.NET MVC combined with AngularJS whereas the server will create a View and pass in a Model and send it to the client. The client will then interact with the View in which case AngularJS steps in to as a local controller. Once submitted the Model or a new Model is passed back to the server controller and handled. (Thus the cycle continues and there are a lot of other translations of this handling when working with sockets or AJAX etc but over all the architecture is identical.)

MVVM is a reactive environment meaning you typically write code (such as triggers) that will activate based on some event. In XAML, where MVVM thrives, this is all easily done with the built in databinding framework BUT as mentioned this will work on any system in any View with any programming language. It is not MS specific. The ViewModel fires (usually a property changed event) and the View reacts to it based on whatever triggers you create. This can get technical but the bottom line is the View is stateless and without logic. It simply changes state based on values. Furthermore, ViewModels are stateless with very little logic, and Models are the State with essentially Zero logic as they should only maintain state. I describe this as application state (Model), state translator (ViewModel), and then the visual state / interaction (View).

In an MVC desktop or client side application you should have a Model, and the Model should be used by the Controller. Based on the Model the controller will modify the View. Views are usually tied to Controllers with Interfaces so that the Controller can work with a variety of Views. In ASP.NET the logic for MVC is slightly backwards on the server as the Controller manages the Models and passes the Models to a selected View. The View is then filled with data based on the model and has it's own logic (usually another MVC set such as done with AngularJS). People will argue and get this confused with application MVC and try to do both at which point maintaining the project will eventually become a disaster. ALWAYS put the logic and control in one location when using MVC. DO NOT write View logic in the code behind of the View (or in the View via JS for web) to accommodate Controller or Model data. Let the Controller change the View. The ONLY logic that should live in a View is whatever it takes to create and run via the Interface it's using. An example of this is submitting a username and password. Whether desktop or web page (on client) the Controller should handle the submit process whenever the View fires the Submit action. If done correctly you can always find your way around an MVC web or local app easily.

MVVM is personally my favorite as it's completely reactive. If a Model changes state the ViewModel listens and translates that state and that's it!!! The View is then listening to the ViewModel for state change and it also updates based on the translation from the ViewModel. Some people call it pure MVVM but there's really only one and I don't care how you argue it and it's always Pure MVVM where the View contains absolutely no logic.

Here's a slight example: Let's say the you want to have a menu slide in on a button press. In MVC you will have a MenuPressed action in your interface. The Controller will know when you click the Menu button and then tell the View to slide in the Menu based on another Interface method such as SlideMenuIn. A round trip for what reason? Incase the Controller decides you can't or wants to do something else instead that's why. The Controller should be in charge of the View with the View doing nothing unless the Controller says so. HOWEVER; in MVVM the slide menu in animation should be built in and generic and instead of being told to slide it in will do so based on some value. So it listens to the ViewModel and when the ViewModel says, IsMenuActive = true (or however) the animation for that takes place. Now, with that said I want to make another point REALLY CLEAR and PLEASE pay attention. IsMenuActive is probably BAD MVVM or ViewModel design. When designing a ViewModel you should never assume a View will have any features at all and just pass translated model state. That way if you decide to change your View to remove the Menu and just show the data / options another way, the ViewModel doesn't care. So how would you manage the Menu? When the data makes sense that's how. So, one way to do this is to give the Menu a list of options (probably an array of inner ViewModels). If that list has data, the Menu then knows to open via the trigger, if not then it knows to hide via the trigger. You simply have data for the menu or not in the ViewModel. DO NOT decide to show / hide that data in the ViewModel.. simply translate the state of the Model. This way the View is completely reactive and generic and can be used in many different situations.

All of this probably makes absolutely no sense if you're not already at least slightly familiar with the architecture of each and learning it can be very confusing as you'll find ALOT OF BAD information on the net.

So... things to keep in mind to get this right. Decide up front how to design your application and STICK TO IT.

If you do MVC, which is great, then make sure you Controller is manageable and in full control of your View. If you have a large View consider adding controls to the View that have different Controllers. JUST DON'T cascade those controllers to different controllers. Very frustrating to maintain. Take a moment and design things separately in a way that will work as separate components... And always let the Controller tell the Model to commit or persist storage. The ideal dependency setup for MVC in is View ? Controller ? Model or with ASP.NET (don't get me started) Model ? View ? Controller ? Model (where Model can be the same or a totally different Model from Controller to View) ...of course the only need to know of Controller in View at this point is mostly for endpoint reference to know where back to pass a Model.

If you do MVVM, I bless your kind soul, but take the time to do it RIGHT! Do not use interfaces for one. Let your View decide how it's going to look based on values. Play with the View with Mock data. If you end up having a View that is showing you a Menu (as per the example) even though you didn't want it at the time then GOOD. You're view is working as it should and reacting based on the values as it should. Just add a few more requirements to your trigger to make sure this doesn't happen when the ViewModel is in a particular translated state or command the ViewModel to empty this state. In your ViewModel DO NOT remove this with internal logic either as if you're deciding from there whether or not the View should see it. Remember you can't assume there is a menu or not in the ViewModel. And finally, the Model should just allow you to change and most likely store state. This is where validation and all will occur; for example, if the Model can't modify the state then it will simply flag itself as dirty or something. When the ViewModel realizes this it will translate what's dirty, and the View will then realize this and show some information via another trigger. All data in the View can be binded to the ViewModel so everything can be dynamic only the Model and ViewModel has absolutely no idea about how the View will react to the binding. As a matter of fact the Model has no idea of a ViewModel either. When setting up dependencies they should point like so and only like so View ? ViewModel ? Model (and a side note here... and this will probably get argued as well but I don't care... DO NOT PASS THE MODEL to the VIEW unless that MODEL is immutable; otherwise wrap it with a proper ViewModel. The View should not see a model period. I give a rats crack what demo you've seen or how you've done it, that's wrong.)

Here's my final tip... Look at a well designed, yet very simple, MVC application and do the same for an MVVM application. One will have more control with limited to zero flexibility while the other will have no control and unlimited flexibility.

A controlled environment is good for managing the entire application from a set of controllers or (a single source) while a reactive environment can be broken up into separate repositories with absolutely no idea of what the rest of the application is doing. Micro managing vs free management.

If I haven't confused you enough try contacting me... I don't mind going over this in full detail with illustration and examples.

At the end of the day we're all programmers and with that anarchy lives within us when coding... So rules will be broken, theories will change, and all of this will end up hog wash... But when working on large projects and on large teams, it really helps to agree on a design pattern and enforce it. One day it will make the small extra steps taken in the beginning become leaps and bounds of savings later.

Cast to generic type in C#

I struggled to solve a similar problem around data table classes instead of messages. The root issue mentioned above of casting a non-generic version of the class to a derived generic version was the same.

In order to allow injection into a portable class library which did not support database libraries, I introduced a set of interface classes, with the intent that I could pass a type and get a matching generic. It ended up needing to implement a generic method.

// Interface for injection
public interface IDatabase
{
    // Original, non-functional signature:
    IDatatable<object> GetDataTable(Type dataType);

    // Functional method using a generic method:
    IDatatable<T> GetDataTable<T>();
}

And this the whole implementation using the generic method above.

The generic class that will be cast from a dictionary.

// Non-generic base class allows listing tables together
abstract class Datatable
{
    Datatable(Type storedClass)
    {
      StoredClass = storedClass;
    }

    Type StoredClass { get; private set; }
}

// Generic inheriting class
abstract class Datatable<T>: Datatable, IDatatable<T>
{
    protected Datatable()
        :base(typeof(T))
    {
    }
}

This is the class that stores the generic class and casts it to satisfy the generic method in the interface

class Database
{
    // Dictionary storing the classes using the non-generic base class
    private Dictionary<Type, Datatable> _tableDictionary;

    protected Database(List<Datatable> tables)
    {
        _tableDictionary = new Dictionary<Type, Datatable>();
        foreach (var table in tables)
        {
            _tableDictionary.Add(table.StoredClass, table);
        }
    }

    // Interface implementation, casts the generic
    public IDatatable<T> GetDataTable<T>()
    {
        Datatable table = null;

        _tableDictionary.TryGetValue(typeof(T), out table);

        return table as IDatatable<T>;
    }
}

And finally the calling of the interface method.

IDatatable<CustomerAccount> table = _database.GetDataTable<CustomerAccount>();

Modify a Column's Type in sqlite3

If you prefer a GUI, DB Browser for SQLite will do this with a few clicks.

  1. "File" - "Open Database"
  2. In the "Database Structure" tab, click on the table content (not table name), then "Edit" menu, "Modify table", and now you can change the data type of any column with a drop down menu. I changed a 'text' field to 'numeric' in order to retrieve data in a number range.

DB Browser for SQLite is open source and free. For Linux it is available from the repository.

How do I programmatically force an onchange event on an input?

ugh don't use eval for anything. Well, there are certain things, but they're extremely rare. Rather, you would do this:

document.getElementById("test").onchange()

Look here for more options: http://jehiah.cz/archive/firing-javascript-events-properly

HtmlSpecialChars equivalent in Javascript?

I am elaborating a bit on o.k.w.'s answer.

You can use the browser's DOM functions for that.

var utils = {
    dummy: document.createElement('div'),
    escapeHTML: function(s) {
        this.dummy.textContent = s
        return this.dummy.innerHTML
    }
}

utils.escapeHTML('<escapeThis>&')

This returns &lt;escapeThis&gt;&amp;

It uses the standard function createElement to create an invisible element, then uses the function textContent to set any string as its content and then innerHTML to get the content in its HTML representation.

How to invoke the super constructor in Python?

Short Answer

super(DerivedClass, self).__init__()

Long Answer

What does super() do?

It takes specified class name, finds its base classes (Python allows multiple inheritance) and looks for the method (__init__ in this case) in each of them from left to right. As soon as it finds method available, it will call it and end the search.

How do I call init of all base classes?

Above works if you have only one base class. But Python does allow multiple inheritance and you might want to make sure all base classes are initialized properly. To do that, you should have each base class call init:

class Base1:
  def __init__():
    super(Base1, self).__init__()

class Base2:
  def __init__():
    super(Base2, self).__init__()

class Derived(Base1, Base2):
  def __init__():
    super(Derived, self).__init__()

What if I forget to call init for super?

The constructor (__new__) gets invoked in a chain (like in C++ and Java). Once the instance is created, only that instance's initialiser (__init__) is called, without any implicit chain to its superclass.

Oracle "SQL Error: Missing IN or OUT parameter at index:: 1"

Based on the comments left above I ran this under sqlplus instead of SQL Developer and the UPDATE statement ran perfectly, leaving me to believe this is an issue in SQL Developer particularly as there was no ORA error number being returned. Thank you for leading me in the right direction.

How to install easy_install in Python 2.7.1 on Windows 7

for 32-bit Python, the installer is here. after you run the installer, you will have easy_install.exe in your \Python27\Scripts directory

if you are looking for 64-bit installers, this is an excellent resource:

http://www.lfd.uci.edu/~gohlke/pythonlibs/

the author has installers for both Setuptools and Distribute. Either one will give you easy_install.exe

How can I check if PostgreSQL is installed or not via Linux script?

For many years I used the command:

ps aux | grep postgres

On one hand it is useful (for any process) and gives useful info (but from process POV). But on the other hand it is for checking if the server you know, you already installed is running.

At some point I found this tutorial, where the usage of the locate command is shown. It looks like this command is much more to the point for this case.

What's the difference between "Solutions Architect" and "Applications Architect"?

Sounds like the same to me! Though I don't totally disagree with Oli. I'd give a selected few people the Software Architect title if they want it but experience tells me the people who would actually deserve the title of Software Architect usually aint that in to titles.

Issue with background color and Google Chrome

I would try what Logan and 1mdm suggested, tho tweak the CSS, but I would really wait for a new Chrome version to come out with fixed bugs, before growing white hair.

IMHO the current Chrome version is still alpha version and was released so that it can spread while it is in development. I personally had issues with table widths, my code worked fine in EVERY browser but could not make it work in Chrome.

How to convert UTF8 string to byte array?

The TextEncoder and TextDecoder Encoding API will let you both encode and decode UTF-8 easily (using typed arrays):

const encoded = new TextEncoder().encode("Ge?a s?? ??sµe");
const decoded = new TextDecoder().decode(encoded);

console.log(encoded, decoded);

Browser support isn't too bad, and there's a polyfill that should work in IE11 and older versions of Edge.


Older versions of TextEncoder supported other different encodings as a string constructor parameter argument, but since Firefox 48 and Chrome 53 this is no-longer supported and TextEncoder and TextDecoder support only UTF-8.

So this will no-longer work in modern web-browsers used since 2016:

new TextDecoder("shift-jis").decode(new Uint8Array(textbuffer))

What is the default font of Sublime Text?

The default font on windows 10 is Consolas

How to get error message when ifstream open fails

You could try letting the stream throw an exception on failure:

std::ifstream f;
//prepare f to throw if failbit gets set
std::ios_base::iostate exceptionMask = f.exceptions() | std::ios::failbit;
f.exceptions(exceptionMask);

try {
  f.open(fileName);
}
catch (std::ios_base::failure& e) {
  std::cerr << e.what() << '\n';
}

e.what(), however, does not seem to be very helpful:

  • I tried it on Win7, Embarcadero RAD Studio 2010 where it gives "ios_base::failbit set" whereas strerror(errno) gives "No such file or directory."
  • On Ubuntu 13.04, gcc 4.7.3 the exception says "basic_ios::clear" (thanks to arne)

If e.what() does not work for you (I don't know what it will tell you about the error, since that's not standardized), try using std::make_error_condition (C++11 only):

catch (std::ios_base::failure& e) {
  if ( e.code() == std::make_error_condition(std::io_errc::stream) )
    std::cerr << "Stream error!\n"; 
  else
    std::cerr << "Unknown failure opening file.\n";
}

How can I get the last day of the month in C#?

Something like:

DateTime today = DateTime.Today;
DateTime endOfMonth = new DateTime(today.Year, today.Month, 1).AddMonths(1).AddDays(-1);

Which is to say that you get the first day of next month, then subtract a day. The framework code will handle month length, leap years and such things.

Incrementing a variable inside a Bash loop

USCOUNTER=$(grep -c "^US " "$FILE")

How to get current working directory in Java?

If you want to get your current working directory then use the following line

System.out.println(new File("").getAbsolutePath());

Convert MySql DateTime stamp into JavaScript's Date format

Recent versions of JavaScript will read an ISO8601 formatted date, so all you have to do is change the space to a 'T', doing something like one of the following:

#MySQL
select date_format(my_date_column,'%Y-%m-%dT%T') from my_table;

#PHP
$php_date_str = substr($mysql_date_str,0,10).'T'.substr($mysql_date_str,11,8);

//JavaScript
js_date_str = mysql_date_str.substr(0,10)+'T'+mysql_date_str.substr(11,8);

gcc-arm-linux-gnueabi command not found

try the following command:

which gcc-arm-linux-gnueabi

Its very likely the command is installed in /usr/bin.

Maven: how to override the dependency added by a library

Alternatively, you can just exclude the dependency that you don't want. STAX is included in JDK 1.6, so if you're using 1.6 you can just exclude it entirely.

My example below is slightly wrong for you - you only need one of the two exclusions but I'm not quite sure which one. There are other versions of Stax floating about, in my example below I was importing A which imported B which imported C & D which each (through yet more transitive dependencies) imported different versions of Stax. So in my dependency on 'A', I excluded both versions of Stax.

<dependency>
  <groupId>a.group</groupId>
  <artifactId>a.artifact</artifactId>
  <version>a.version</version>
  <exclusions>
    <!--  STAX comes with Java 1.6 -->
    <exclusion>
      <artifactId>stax-api</artifactId>
      <groupId>javax.xml.stream</groupId>
    </exclusion>
    <exclusion>
      <artifactId>stax-api</artifactId>
      <groupId>stax</groupId>
    </exclusion>
  </exclusions>
<dependency>

Scroll RecyclerView to show selected item on top

just call this method simply:

((LinearLayoutManager)recyclerView.getLayoutManager()).scrollToPositionWithOffset(yourItemPosition,0);

instead of:

recyclerView.scrollToPosition(yourItemPosition);