Programs & Examples On #Data execution prevention

Data Execution Prevention (DEP) is a security feature of modern operating systems and CPUs intended to prevent the execution of code/data located in a memory region not explicitly marked as executable.

Grouping into interval of 5 minutes within a time range

I found out that with MySQL probably the correct query is the following:

SELECT SUBSTRING( FROM_UNIXTIME( CEILING( timestamp /300 ) *300,  
                                 '%Y-%m-%d %H:%i:%S' ) , 1, 19 ) AS ts_CEILING,
SUM(value)
FROM group_interval
GROUP BY SUBSTRING( FROM_UNIXTIME( CEILING( timestamp /300 ) *300,  
                                   '%Y-%m-%d %H:%i:%S' ) , 1, 19 )
ORDER BY SUBSTRING( FROM_UNIXTIME( CEILING( timestamp /300 ) *300,  
                                   '%Y-%m-%d %H:%i:%S' ) , 1, 19 ) DESC

Let me know what you think.

How to use gitignore command in git

There are several ways to use gitignore git

  • specifying by the specific filename. for example, to ignore a file
    called readme.txt, just need to write readme.txt in .gitignore file.
  • you can also write the name of the file extension. For example, to
    ignore all .txt files, write *.txt.
  • you can also ignore a whole folder. for example you want to ignore
    folder named test. Then just write test/ in the file.

just create a .gitignore file and write in whatever you want to ignore a sample gitignore file would be:

# NPM packages folder.
node_modules

# Build files
dist/

# lock files
yarn.lock
package-lock.json

# Logs
logs
*.log
npm-debug.log*

# node-waf configuration
.lock-wscript

# Optional npm cache directory
.npm

# Optional REPL history
.node_repl_history

# Jest Coverage
coverage

.history/

You can find more on git documentation gitignore

reStructuredText tool support

Salvaging (and extending) the list from an old version of the Wikipedia page:

Documentation

Implementations

Although the reference implementation of reStructuredText is written in Python, there are reStructuredText parsers in other languages too.

Python - Docutils

The main distribution of reStructuredText is the Python Docutils package. It contains several conversion tools:

  • rst2html - from reStructuredText to HTML
  • rst2xml - from reStructuredText to XML
  • rst2latex - from reStructuredText to LaTeX
  • rst2odt - from reStructuredText to ODF Text (word processor) document.
  • rst2s5 - from reStructuredText to S5, a Simple Standards-based Slide Show System
  • rst2man - from reStructuredText to Man page

Haskell - Pandoc

Pandoc is a Haskell library for converting from one markup format to another, and a command-line tool that uses this library. It can read Markdown and (subsets of) reStructuredText, HTML, and LaTeX, and it can write Markdown, reStructuredText, HTML, LaTeX, ConTeXt, PDF, RTF, DocBook XML, OpenDocument XML, ODT, GNU Texinfo, MediaWiki markup, groff man pages, and S5 HTML slide shows.

There is an Pandoc online tool (POT) to try this library. Unfortunately, compared to the reStructuredText online renderer (ROR),

  • POT truncates input rather more shortly. The POT user must render input in chunks that could be rendered whole by the ROR.
  • POT output lacks the helpful error messages displayed by the ROR (and generated by docutils)

Java - JRst

JRst is a Java reStructuredText parser. It can currently output HTML, XHTML, DocBook xdoc and PDF, BUT seems to have serious problems: neither PDF or (X)HTML generation works using the current full download, result pages in (X)HTML are empty and PDF generation fails on IO problems with XSL files (not bundled??). Note that the original JRst has been removed from the website; a fork is found on GitHub.

Scala - Laika

Laika is a new library for transforming markup languages to other output formats. Currently it supports input from Markdown and reStructuredText and produce HTML output. The library is written in Scala but should be also usable from Java.

Perl

PHP

C#/.NET

Nim/C

The Nim compiler features the commands rst2htmland rst2tex which transform reStructuredText files to HTML and TeX files. The standard library provides the following modules (used by the compiler) to handle reStructuredText files programmatically:

  • rst - implements a reStructuredText parser
  • rstast - implements an AST for the reStructuredText parser
  • rstgen - implements a generator of HTML/Latex from reStructuredText

Other 3rd party converters

Most (but not all) of these tools are based on Docutils (see above) and provide conversion to or from formats that might not be supported by the main distribution.

From reStructuredText

  • restview - This pip-installable python package requires docutils, which does the actual rendering. restview's major ease-of-use feature is that, when you save changes to your document(s), it automagically re-renders and re-displays them. restview
    1. starts a small web server
    2. calls docutils to render your document(s) to HTML
    3. calls your device's browser to display the output HTML.
  • rst2pdf - from reStructuredText to PDF
  • rst2odp - from reStructuredText to ODF Presentation
  • rst2beamer - from reStructuredText to LaTeX beamer Presentation class
  • Wikir - from reStructuredText to a Google (and possibly other) Wiki formats
  • rst2qhc - Convert a collection of reStructuredText files into a Qt (toolkit) Help file and (optional) a Qt Help Project file

To reStructuredText

  • xml2rst is an XSLT script to convert Docutils internal XML representation (back) to reStructuredText
  • Pandoc (see above) can also convert from Markdown, HTML and LaTeX to reStructuredText
  • db2rst is a simple and limited DocBook to reStructuredText translator
  • pod2rst - convert .pod files to reStructuredText files

Extensions

Some projects use reStructuredText as a baseline to build on, or provide extra functionality extending the utility of the reStructuredText tools.

Sphinx

The Sphinx documentation generator translates a set of reStructuredText source files into various output formats, automatically producing cross-references, indices etc.

rest2web

rest2web is a simple tool that lets you build your website from a single template (or as many as you want), and keep the contents in reStructuredText.

Pygments

Pygments is a generic syntax highlighter for general use in all kinds of software such as forum systems, Wikis or other applications that need to prettify source code. See Using Pygments in reStructuredText documents.

Free Editors

While any plain text editor is suitable to write reStructuredText documents, some editors have better support than others.

Emacs

The Emacs support via rst-mode comes as part of the Docutils package under /docutils/tools/editors/emacs/rst.el

Vim

The vim-common package for that comes with most GNU/Linux distributions has reStructuredText syntax highlight and indentation support of reStructuredText out of the box:

Jed

There is a rst mode for the Jed programmers editor.

gedit

gedit, the official text editor of the GNOME desktop environment. There is a gedit reStructuredText plugin.

Geany

Geany, a small and lightweight Integrated Development Environment include support for reStructuredText from version 0.12 (October 10, 2007).

Leo

Leo, an outlining editor for programmers, supports reStructuredText via rst-plugin or via "@auto-rst" nodes (it's not well-documented, but @auto-rst nodes allow editing rst files directly, parsing the structure into the Leo outline).

It also provides a way to preview the resulting HTML, in a "viewrendered" pane.

FTE

The FTE Folding Text Editor - a free (licensed under the GNU GPL) text editor for developers. FTE has a mode for reStructuredText support. It provides color highlighting of basic RSTX elements and special menu that provide easy way to insert most popular RSTX elements to a document.

PyK

PyK is a successor of PyEdit and reStInPeace, written in Python with the help of the Qt4 toolkit.

Eclipse

The Eclipse IDE with the ReST Editor plug-in provides support for editing reStructuredText files.

NoTex

NoTex is a browser based (general purpose) text editor, with integrated project management and syntax highlighting. Plus it enables to write books, reports, articles etc. using rST and convert them to LaTex, PDF or HTML. The PDF files are of high publication quality and are produced via Sphinx with the Texlive LaTex suite.

Notepad++

Notepad++ is a general purpose text editor for Windows. It has syntax highlighting for many languages built-in and support for reStructuredText via a user defined language for reStructuredText.

Visual Studio Code

Visual Studio Code is a general purpose text editor for Windows/macOS/Linux. It has syntax highlighting for many languages built-in and supports reStructuredText via an extension from LeXtudio.

Dedicated reStructuredText Editors

Proprietary editors

Sublime Text

Sublime Text is a completely customizable and extensible source code editor available for Windows, OS X, and Linux. Registration is required for long-term use, but all functions are available in the unregistered version, with occasional reminders to purchase a license. Versions 2 and 3 (currently in beta) support reStructuredText syntax highlighting by default, and several plugins are available through the package manager Package Control to provide snippets and code completion, additional syntax highlighting, conversion to/from RST and other formats, and HTML preview in the browser.

BBEdit / TextWrangler

BBEdit (and its free variant TextWrangler) for Mac can syntax-highlight reStructuredText using this codeless language module.

TextMate

TextMate, a proprietary general-purpose GUI text editor for Mac OS X, has a bundle for reStructuredText.

Intype

Intype is a proprietary text editor for Windows, that support reStructuredText out of the box.

E Text Editor

E is a proprietary Text Editor licensed under the "Open Company License". It supports TextMate's bundles, so it should support reStructuredText the same way TextMate does.

PyCharm

PyCharm (and other IntelliJ platform IDEs?) has ReST/Sphinx support (syntax highlighting, autocomplete and preview).instant preview)

Wiki

here are some Wiki programs that support the reStructuredText markup as the native markup syntax, or as an add-on:

MediaWiki

MediaWiki reStructuredText extension allows for reStructuredText markup in MediaWiki surrounded by <rst> and </rst>.

MoinMoin

MoinMoin is an advanced, easy to use and extensible WikiEngine with a large community of users. Said in a few words, it is about collaboration on easily editable web pages.

There is a reStructuredText Parser for MoinMoin.

Trac

Trac is an enhanced wiki and issue tracking system for software development projects. There is a reStructuredText Support in Trac.

This Wiki

This Wiki is a Webware for Python Wiki written by Ian Bicking. This wiki uses ReStructuredText for its markup.

rstiki

rstiki is a minimalist single-file personal wiki using reStructuredText syntax (via docutils) inspired by pwyky. It does not support authorship indication, versioning, hierarchy, chrome/framing/templating or styling. It leverages docutils/reStructuredText as the wiki syntax. As such, it's under 200 lines of code, and in a single file. You put it in a directory and it runs.

ikiwiki

Ikiwiki is a wiki compiler. It converts wiki pages into HTML pages suitable for publishing on a website. Ikiwiki stores pages and history in a revision control system such as Subversion or Git. There are many other features, including support for blogging, as well as a large array of plugins. It's reStructuredText plugin, however is somewhat limited and is not recommended as its' main markup language at this time.

Web Services

Sandbox

An Online reStructuredText editor can be used to play with the markup and see the results immediately.

Blogging frameworks

WordPress

WordPreSt reStructuredText plugin for WordPress. (PHP)

Zine

reStructuredText parser plugin for Zine (will become obsolete in version 0.2 when Zine is scheduled to get a native reStructuredText support). Zine is discontinued. (Python)

pelican

Pelican is a static blog generator that supports writing articles in ReST. (Python)

hyde

Hyde is a static website generator that supports ReST. (Python)

Acrylamid

Acrylamid is a static blog generator that supports writing articles in ReST. (Python)

Nikola

Nikola is a Static Site and Blog Generator that supports ReST. (Python)

ipsum genera

Ipsum genera is a static blog generator written in Nim.

Yozuch

Yozuch is a static blog generator written in Python.

More

Python: list of lists

Lists are a mutable type - in order to create a copy (rather than just passing the same list around), you need to do so explicitly:

listoflists.append((list[:], list[0]))

However, list is already the name of a Python built-in - it'd be better not to use that name for your variable. Here's a version that doesn't use list as a variable name, and makes a copy:

listoflists = []
a_list = []
for i in range(0,10):
    a_list.append(i)
    if len(a_list)>3:
        a_list.remove(a_list[0])
        listoflists.append((list(a_list), a_list[0]))
print listoflists

Note that I demonstrated two different ways to make a copy of a list above: [:] and list().

The first, [:], is creating a slice (normally often used for getting just part of a list), which happens to contain the entire list, and thus is effectively a copy of the list.

The second, list(), is using the actual list type constructor to create a new list which has contents equal to the first list. (I didn't use it in the first example because you were overwriting that name in your code - which is a good example of why you don't want to do that!)

Print a file's last modified date in Bash

Adding to @StevePenny answer, you might want to cut the not-so-human-readable part:

stat -c%y Localizable.strings | cut -d'.' -f1

Difference between multitasking, multithreading and multiprocessing?

Multi-programming :-

More than one task(job) process can reside into main memory at a time. It is basically design to reduce CPU wastage during I/O operation , example : if a job is executing currently and need I/O operation . I/O operation is done using DMA and processor assign to some Other job from the job queue till I/O operation of job1 completed . then job1 continue again . In this way it reduce CPU wastage .

Objects are not valid as a React child. If you meant to render a collection of children, use an array instead

I also occured the error,and I sloved it by removing the curly braces,hope it will help someone else.

You can see that ,I did not put the con in the curly brace,and the error occured ,when I remove the burly brace , the error disappeared.

const modal = (props) => {
const { show, onClose } = props;

let con = <div className="modal" onClick={onClose}>
        {props.children}
        </div>;

return show === true ? (
    {con}
) : (
    <div>hello</div>
);

There are an article about the usage of the curly brace.click here

How do I get the result of a command in a variable in windows?

I would like to add a remark to the above solutions:

All these syntaxes work perfectly well IF YOUR COMMAND IS FOUND WITHIN THE PATH or IF THE COMMAND IS A cmdpath WITHOUT SPACES OR SPECIAL CHARACTERS.

But if you try to use an executable command located in a folder which path contains special characters then you would need to enclose your command path into double quotes (") and then the FOR /F syntax does not work.

Examples:

$ for /f "tokens=* USEBACKQ" %f in (
    `""F:\GLW7\Distrib\System\Shells and scripting\f2ko.de\folderbrowse.exe"" Hello '"F:\GLW7\Distrib\System\Shells and scripting"'`
) do echo %f
The filename, directory name, or volume label syntax is incorrect.

or

$ for /f "tokens=* USEBACKQ" %f in (
      `"F:\GLW7\Distrib\System\Shells and scripting\f2ko.de\folderbrowse.exe" "Hello World" "F:\GLW7\Distrib\System\Shells and scripting"`
) do echo %f
'F:\GLW7\Distrib\System\Shells' is not recognized as an internal or external command, operable program or batch file.

or

`$ for /f "tokens=* USEBACKQ" %f in (
     `""F:\GLW7\Distrib\System\Shells and scripting\f2ko.de\folderbrowse.exe"" "Hello World" "F:\GLW7\Distrib\System\Shells and scripting"`
) do echo %f
'"F:\GLW7\Distrib\System\Shells and scripting\f2ko.de\folderbrowse.exe"" "Hello' is not recognized as an internal or external command, operable program or batch file.

In that case, the only solution I found to use a command and store its result in a variable is to set (temporarily) the default directory to the one of command itself :

pushd "%~d0%~p0"
FOR /F "tokens=* USEBACKQ" %%F IN (
    `FOLDERBROWSE "Hello world!" "F:\GLW7\Distrib\System\Layouts (print,display...)"`
) DO (SET MyFolder=%%F)
popd
echo My selected folder: %MyFolder%

The result is then correct:

My selected folder: F:\GLW7\Distrib\System\OS install, recovery, VM\
Press any key to continue . . .

Of course in the above example, I assume that my batch script is located in the same folder as the one of my executable command so that I can use the "%~d0%~p0" syntax. If this is not your case, then you have to find a way to locate your command path and change the default directory to its path.

NB: For those who wonder, the sample command used here (to select a folder) is FOLDERBROWSE.EXE. I found it on the web site f2ko.de (http://f2ko.de/en/cmd.php).

If anyone has a better solution for that kind of commands accessible through a complex path, I will be very glad to hear of it.

Gilles

Replacing blank values (white space) with NaN in pandas

These are all close to the right answer, but I wouldn't say any solve the problem while remaining most readable to others reading your code. I'd say that answer is a combination of BrenBarn's Answer and tuomasttik's comment below that answer. BrenBarn's answer utilizes isspace builtin, but does not support removing empty strings, as OP requested, and I would tend to attribute that as the standard use case of replacing strings with null.

I rewrote it with .apply, so you can call it on a pd.Series or pd.DataFrame.


Python 3:

To replace empty strings or strings of entirely spaces:

df = df.apply(lambda x: np.nan if isinstance(x, str) and (x.isspace() or not x) else x)

To replace strings of entirely spaces:

df = df.apply(lambda x: np.nan if isinstance(x, str) and x.isspace() else x)

To use this in Python 2, you'll need to replace str with basestring.

Python 2:

To replace empty strings or strings of entirely spaces:

df = df.apply(lambda x: np.nan if isinstance(x, basestring) and (x.isspace() or not x) else x)

To replace strings of entirely spaces:

df = df.apply(lambda x: np.nan if isinstance(x, basestring) and x.isspace() else x)

How to add chmod permissions to file in Git?

Antwane's answer is correct, and this should be a comment but comments don't have enough space and do not allow formatting. :-) I just want to add that in Git, file permissions are recorded only1 as either 644 or 755 (spelled (100644 and 100755; the 100 part means "regular file"):

diff --git a/path b/path
new file mode 100644

The former—644—means that the file should not be executable, and the latter means that it should be executable. How that turns into actual file modes within your file system is somewhat OS-dependent. On Unix-like systems, the bits are passed through your umask setting, which would normally be 022 to remove write permission from "group" and "other", or 002 to remove write permission only from "other". It might also be 077 if you are especially concerned about privacy and wish to remove read, write, and execute permission from both "group" and "other".


1Extremely-early versions of Git saved group permissions, so that some repositories have tree entries with mode 664 in them. Modern Git does not, but since no part of any object can ever be changed, those old permissions bits still persist in old tree objects.

The change to store only 0644 or 0755 was in commit e44794706eeb57f2, which is before Git v0.99 and dated 16 April 2005.

Checking character length in ruby

Instead of using a regular expression, just check if string.length > 25

Getting multiple values with scanf()

Could do this, but then the user has to separate the numbers by a space:

#include "stdio.h"

int main()
{
    int minx, x, y, z;

    printf("Enter four ints: ");
    scanf( "%i %i %i %i", &minx, &x, &y, &z);

    printf("You wrote: %i %i %i %i", minx, x, y, z);
}

How do I enable NuGet Package Restore in Visual Studio?

Package Manager console (Visual Studio, Tools > NuGet Package Manager > Package Manager Console): Run the Update-Package -reinstall -ProjectName command where is the name of the affected project as it appears in Solution Explorer. Use Update-Package -reinstall by itself to restore all packages in the solution. See Update-Package. You can also reinstall a single package, if desired.

from https://docs.microsoft.com/en-us/nuget/quickstart/restore

Java - Opposite of .contains (does not contain)

It seems that Luiggi Mendoza and joey rohan both already answered this, but I think it can be clarified a little.

You can write it as a single if statement:

if (inventory.contains("bread") && !inventory.contains("water")) {
    // do something
}

Joining three tables using MySQL

For normalize form

select e1.name as 'Manager', e2.name as 'Staff'
from employee e1 
left join manage m on m.mid = e1.id
left join employee e2 on m.eid = e2.id

Error: JavaFX runtime components are missing, and are required to run this application with JDK 11

This worked for me:

File >> Project Structure >> Modules >> Dependency >> + (on left-side of window)

clicking the "+" sign will let you designate the directory where you have unpacked JavaFX's "lib" folder.

Scope is Compile (which is the default.) You can then edit this to call it JavaFX by double-clicking on the line.

then in:

Run >> Edit Configurations

Add this line to VM Options:

--module-path /path/to/JavaFX/lib --add-modules=javafx.controls

(oh and don't forget to set the SDK)

Is it possible to use Java 8 for Android development?

Yes, Android Supports Java 8 Now (24.1.17)

Now it is possible

But you will need to have your device rom run on java 1.8 and enable "jackOptions" to run it. Jack is the name for the new Android compiler that runs Java 8

https://developer.android.com/guide/platform/j8-jack.html

add these lines to build_gradle

    android {
  ...
  defaultConfig {
    ...
    jackOptions {
      enabled true
    }
  }
  compileOptions {
    sourceCompatibility JavaVersion.VERSION_1_8
    targetCompatibility JavaVersion.VERSION_1_8
  }
}

Java 8 seem to be the running java engine of Android studio 2.0, But it still does not accept the syntax of java 8 after I checked, and you cannot chose a compiler from android studio now. However, you can use the scala plugin if you need functional programming mechanism in your android client.

enter image description here

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

The General Idea

Please see the answer by Martin Smith for a better illustations and explanations of the different joins, including and especially differences between FULL OUTER JOIN, RIGHT OUTER JOIN and LEFT OUTER JOIN.

These two table form a basis for the representation of the JOINs below:

Basis

CROSS JOIN

CrossJoin

SELECT *
  FROM citizen
 CROSS JOIN postalcode

The result will be the Cartesian products of all combinations. No JOIN condition required:

CrossJoinResult

INNER JOIN

INNER JOIN is the same as simply: JOIN

InnerJoin

SELECT *
  FROM citizen    c
  JOIN postalcode p ON c.postal = p.postal

The result will be combinations that satisfies the required JOIN condition:

InnerJoinResult

LEFT OUTER JOIN

LEFT OUTER JOIN is the same as LEFT JOIN

LeftJoin

SELECT *
  FROM citizen         c
  LEFT JOIN postalcode p ON c.postal = p.postal

The result will be everything from citizen even if there are no matches in postalcode. Again a JOIN condition is required:

LeftJoinResult

Data for playing

All examples have been run on an Oracle 18c. They're available at dbfiddle.uk which is also where screenshots of tables came from.

CREATE TABLE citizen (id      NUMBER,
                      name    VARCHAR2(20),
                      postal  NUMBER,  -- <-- could do with a redesign to postalcode.id instead.
                      leader  NUMBER);

CREATE TABLE postalcode (id      NUMBER,
                         postal  NUMBER,
                         city    VARCHAR2(20),
                         area    VARCHAR2(20));

INSERT INTO citizen (id, name, postal, leader)
              SELECT 1, 'Smith', 2200,  null FROM DUAL
        UNION SELECT 2, 'Green', 31006, 1    FROM DUAL
        UNION SELECT 3, 'Jensen', 623,  1    FROM DUAL;

INSERT INTO postalcode (id, postal, city, area)
                 SELECT 1, 2200,     'BigCity',         'Geancy'  FROM DUAL
           UNION SELECT 2, 31006,    'SmallTown',       'Snizkim' FROM DUAL
           UNION SELECT 3, 31006,    'Settlement',      'Moon'    FROM DUAL  -- <-- Uuh-uhh.
           UNION SELECT 4, 78567390, 'LookoutTowerX89', 'Space'   FROM DUAL;

Blurry boundaries when playing with JOIN and WHERE

CROSS JOIN

CROSS JOIN resulting in rows as The General Idea/INNER JOIN:

SELECT *
  FROM citizen          c
  CROSS JOIN postalcode p
 WHERE c.postal = p.postal -- < -- The WHERE condition is limiting the resulting rows

Using CROSS JOIN to get the result of a LEFT OUTER JOIN requires tricks like adding in a NULL row. It's omitted.

INNER JOIN

INNER JOIN becomes a cartesian products. It's the same as The General Idea/CROSS JOIN:

SELECT *
  FROM citizen    c
  JOIN postalcode p ON 1 = 1  -- < -- The ON condition makes it a CROSS JOIN

This is where the inner join can really be seen as the cross join with results not matching the condition removed. Here none of the resulting rows are removed.

Using INNER JOIN to get the result of a LEFT OUTER JOIN also requires tricks. It's omitted.

LEFT OUTER JOIN

LEFT JOIN results in rows as The General Idea/CROSS JOIN:

SELECT *
  FROM citizen         c
  LEFT JOIN postalcode p ON 1 = 1 -- < -- The ON condition makes it a CROSS JOIN

LEFT JOIN results in rows as The General Idea/INNER JOIN:

SELECT *
  FROM citizen         c
  LEFT JOIN postalcode p ON c.postal = p.postal
 WHERE p.postal IS NOT NULL -- < -- removed the row where there's no mathcing result from postalcode

The troubles with the Venn diagram

An image internet search on "sql join cross inner outer" will show a multitude of Venn diagrams. I used to have a printed copy of one on my desk. But there are issues with the representation.

Venn diagram are excellent for set theory, where an element can be in one or both sets. But for databases, an element in one "set" seem, to me, to be a row in a table, and therefore not also present in any other tables. There is no such thing as one row present in multiple tables. A row is unique to the table.

Self joins are a corner case where each element is in fact the same in both sets. But it's still not free of any of the issues below.

The set A represents the set on the left (the citizen table) and the set B is the set on the right (the postalcode table) in below discussion.

CROSS JOIN

Every element in both sets are matched with every element in the other set, meaning we need A amount of every B elements and B amount of every A elements to properly represent this Cartesian product. Set theory isn't made for multiple identical elements in a set, so I find Venn diagrams to properly represent it impractical/impossible. It doesn't seem that UNION fits at all.

The rows are distinct. The UNION is 7 rows in total. But they're incompatible for a common SQL results set. And this is not how a CROSS JOIN works at all:

CrossJoinUnion1

Trying to represent it like this:

CrossJoinUnion2Crossing

..but now it just looks like an INTERSECTION, which it's certainly not. Furthermore there's no element in the INTERSECTION that is actually in any of the two distinct sets. However, it looks very much like the searchable results similar to this:

CrossJoinUnionUnion3

For reference one searchable result for CROSS JOINs can be seen at Tutorialgateway. The INTERSECTION, just like this one, is empty.

INNER JOIN

The value of an element depends on the JOIN condition. It's possible to represent this under the condition that every row becomes unique to that condition. Meaning id=x is only true for one row. Once a row in table A (citizen) matches multiple rows in table B (postalcode) under the JOIN condition, the result has the same problems as the CROSS JOIN: The row needs to be represented multiple times, and the set theory isn't really made for that. Under the condition of uniqueness, the diagram could work though, but keep in mind that the JOIN condition determines the placement of an element in the diagram. Looking only at the values of the JOIN condition with the rest of the row just along for the ride:

InnerJoinIntersection - Filled

This representation falls completely apart when using an INNER JOIN with a ON 1 = 1 condition making it into a CROSS JOIN.

With a self-JOIN, the rows are in fact idential elements in both tables, but representing the tables as both A and B isn't very suitable. For example a common self-JOIN condition that makes an element in A to be matching a different element in B is ON A.parent = B.child, making the match from A to B on seperate elements. From the examples that would be a SQL like this:

SELECT *
  FROM citizen c1
  JOIN citizen c2 ON c1.id = c2.leader

SelfJoinResult

Meaning Smith is the leader of both Green and Jensen.

OUTER JOIN

Again the troubles begin when one row has multiple matches to rows in the other table. This is further complicated because the OUTER JOIN can be though of as to match the empty set. But in set theory the union of any set C and an empty set, is always just C. The empty set adds nothing. The representation of this LEFT OUTER JOIN is usually just showing all of A to illustrate that rows in A are selected regardless of whether there is a match or not from B. The "matching elements" however has the same problems as the illustration above. They depend on the condition. And the empty set seems to have wandered over to A:

LeftJoinIntersection - Filled

WHERE clause - making sense

Finding all rows from a CROSS JOIN with Smith and postalcode on the Moon:

SELECT *
  FROM citizen          c
 CROSS JOIN postalcode  p
 WHERE c.name = 'Smith'
   AND p.area = 'Moon';

Where - result

Now the Venn diagram isn't used to reflect the JOIN. It's used only for the WHERE clause:

Where

..and that makes sense.

When INTERSECT and UNION makes sense

INTERSECT

As explained an INNER JOIN is not really an INTERSECT. However INTERSECTs can be used on results of seperate queries. Here a Venn diagram makes sense, because the elements from the seperate queries are in fact rows that either belonging to just one of the results or both. Intersect will obviously only return results where the row is present in both queries. This SQL will result in the same row as the one above WHERE, and the Venn diagram will also be the same:

SELECT *
  FROM citizen          c
 CROSS JOIN postalcode  p
 WHERE c.name = 'Smith'
INTERSECT
SELECT *
  FROM citizen          c
 CROSS JOIN postalcode  p
 WHERE p.area = 'Moon';

UNION

An OUTER JOIN is not a UNION. However UNION work under the same conditions as INTERSECT, resulting in a return of all results combining both SELECTs:

SELECT *
  FROM citizen          c
 CROSS JOIN postalcode  p
 WHERE c.name = 'Smith'
UNION
SELECT *
  FROM citizen          c
 CROSS JOIN postalcode  p
 WHERE p.area = 'Moon';

which is equivalent to:

SELECT *
  FROM citizen          c
 CROSS JOIN postalcode  p
 WHERE c.name = 'Smith'
   OR p.area = 'Moon';

..and gives the result:

Union - Result

Also here a Venn diagram makes sense:

UNION

When it doesn't apply

An important note is that these only work when the structure of the results from the two SELECT's are the same, enabling a comparison or union. The results of these two will not enable that:

SELECT *
  FROM citizen
 WHERE name = 'Smith'
SELECT *
  FROM postalcode
 WHERE area = 'Moon';

..trying to combine the results with UNION gives a

ORA-01790: expression must have same datatype as corresponding expression

For further interest read Say NO to Venn Diagrams When Explaining JOINs and sql joins as venn diagram. Both also cover EXCEPT.

How to convert string to Date in Angular2 \ Typescript?

You can use date filter to convert in date and display in specific format.

In .ts file (typescript):

let dateString = '1968-11-16T00:00:00' 
let newDate = new Date(dateString);

In HTML:

{{dateString |  date:'MM/dd/yyyy'}}

Below are some formats which you can implement :

Backend:

public todayDate = new Date();

HTML :

<select>
<option value=""></option>
<option value="MM/dd/yyyy">[{{todayDate | date:'MM/dd/yyyy'}}]</option>
<option value="EEEE, MMMM d, yyyy">[{{todayDate | date:'EEEE, MMMM d, yyyy'}}]</option>
<option value="EEEE, MMMM d, yyyy h:mm a">[{{todayDate | date:'EEEE, MMMM d, yyyy h:mm a'}}]</option>
<option value="EEEE, MMMM d, yyyy h:mm:ss a">[{{todayDate | date:'EEEE, MMMM d, yyyy h:mm:ss a'}}]</option>
<option value="MM/dd/yyyy h:mm a">[{{todayDate | date:'MM/dd/yyyy h:mm a'}}]</option>
<option value="MM/dd/yyyy h:mm:ss a">[{{todayDate | date:'MM/dd/yyyy h:mm:ss a'}}]</option>
<option value="MMMM d">[{{todayDate | date:'MMMM d'}}]</option>   
<option value="yyyy-MM-ddTHH:mm:ss">[{{todayDate | date:'yyyy-MM-ddTHH:mm:ss'}}]</option>
<option value="h:mm a">[{{todayDate | date:'h:mm a'}}]</option>
<option value="h:mm:ss a">[{{todayDate | date:'h:mm:ss a'}}]</option>      
<option value="EEEE, MMMM d, yyyy hh:mm:ss a">[{{todayDate | date:'EEEE, MMMM d, yyyy hh:mm:ss a'}}]</option>
<option value="MMMM yyyy">[{{todayDate | date:'MMMM yyyy'}}]</option> 
</select>

Equivalent of *Nix 'which' command in PowerShell?

This seems to do what you want (I found it on http://huddledmasses.org/powershell-find-path/):

Function Find-Path($Path, [switch]$All = $false, [Microsoft.PowerShell.Commands.TestPathType]$type = "Any")
## You could comment out the function stuff and use it as a script instead, with this line:
#param($Path, [switch]$All = $false, [Microsoft.PowerShell.Commands.TestPathType]$type = "Any")
   if($(Test-Path $Path -Type $type)) {
      return $path
   } else {
      [string[]]$paths = @($pwd);
      $paths += "$pwd;$env:path".split(";")

      $paths = Join-Path $paths $(Split-Path $Path -leaf) | ? { Test-Path $_ -Type $type }
      if($paths.Length -gt 0) {
         if($All) {
            return $paths;
         } else {
            return $paths[0]
         }
      }
   }
   throw "Couldn't find a matching path of type $type"
}
Set-Alias find Find-Path

Does `anaconda` create a separate PYTHONPATH variable for each new environment?

Anaconda does not use the PYTHONPATH. One should however note that if the PYTHONPATH is set it could be used to load a library that is not in the anaconda environment. That is why before activating an environment it might be good to do a

unset PYTHONPATH

For instance this PYTHONPATH points to an incorrect pandas lib:

export PYTHONPATH=/home/john/share/usr/anaconda/lib/python
source activate anaconda-2.7
python
>>>> import pandas as pd
/home/john/share/usr/lib/python/pandas-0.12.0-py2.7-linux-x86_64.egg/pandas/hashtable.so: undefined symbol: PyUnicodeUCS2_DecodeUTF8
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/home/john/share/usr/lib/python/pandas-0.12.0-py2.7-linux-x86_64.egg/pandas/__init__.py", line 6, in <module>
    from . import hashtable, tslib, lib
ImportError: /home/john/share/usr/lib/python/pandas-0.12.0-py2.7-linux-x86_64.egg/pandas/hashtable.so: undefined symbol: PyUnicodeUCS2_DecodeUTF8

unsetting the PYTHONPATH prevents the wrong pandas lib from being loaded:

unset PYTHONPATH
source activate anaconda-2.7
python
>>>> import pandas as pd
>>>>

Where is SQL Server Management Studio 2012?

Run PowerShell and type:

gci -Path "C:\Program Files*\Microsoft SQL Server" -Recurse -Include "Ssms.exe" | Select -ExpandProperty FullName

To prevent a memory leak, the JDBC Driver has been forcibly unregistered

I found the same issue with Tomcat version 6.026.

I used the Mysql JDBC.jar in WebAPP Library as well as in TOMCAT Lib.

To fix the above by removing the Jar from the TOMCAT lib folder.

So what I understand is that TOMCAT is handling the JDBC memory leak properly. But if the MYSQL Jdbc jar is duplicated in WebApp and Tomcat Lib, Tomcat will only be able to handle the jar present in the Tomcat Lib folder.

Flutter: RenderBox was not laid out

Reason for the error:

Column tries to expands in vertical axis, and so does the ListView, hence you need to constrain the height of ListView.


Solutions

  1. Use either Expanded or Flexible if you want to allow ListView to take up entire left space in Column.

    Column(
      children: <Widget>[
        Expanded(
          child: ListView(...),
        )
      ],
    )
    

  1. Use SizedBox if you want to restrict the size of ListView to a certain height.

    Column(
      children: <Widget>[
        SizedBox(
          height: 200, // constrain height
          child: ListView(),
        )
      ],
    )
    

  1. Use shrinkWrap, if your ListView isn't too big.

    Column(
      children: <Widget>[
        ListView(
          shrinkWrap: true, // use it
        )
      ],
    )
    

Read text file into string array (and write)

If you don't care about loading the file into memory, as of Go 1.16, you can use the os.ReadFile and bytes.Count functions.

package main

import (
    "log"
    "os"
    "bytes"
)

func main() {
    data, err := os.ReadFile("input.txt")
    if err != nil {
        log.Fatal(err)
    }

    n := bytes.Count(data, []byte{'\n'})

    fmt.Printf("input.txt has %d lines\n", n)
}

Jquery Setting Value of Input Field

If the input field has a class name formData use this : $(".formData").val("data")

If the input field has an id attribute name formData use this : $("#formData").val("data")

If the input name is given use this : $("input[name='formData']").val("data")

You can also mention the type. Then it will refer to all the inputs of that type and the given class name: $("input[type='text'].formData").val("data")

Fatal error: [] operator not supported for strings

Solved!

$a['index'] = [];
$a['index'][] = 'another value';
$a['index'][] = 'another value';
$a['index'][] = 'another value';
$a['index'][] = 'another value';

Python - List of unique dictionaries

Expanding on John La Rooy (Python - List of unique dictionaries) answer, making it a bit more flexible:

def dedup_dict_list(list_of_dicts: list, columns: list) -> list:
    return list({''.join(row[column] for column in columns): row
                for row in list_of_dicts}.values())

Calling Function:

sorted_list_of_dicts = dedup_dict_list(
    unsorted_list_of_dicts, ['id', 'name'])

Send SMTP email using System.Net.Mail via Exchange Online (Office 365)

In year of 2020, these code seems to return exception as

System.Net.Mail.SmtpStatusCode.MustIssueStartTlsFirst or The SMTP server requires a secure connection or the client was not authenticated. The server response was: 5.7.57 SMTP; Client was not authenticated to send anonymous mail during MAIL FROM

This code is working for me.

            using (SmtpClient client = new SmtpClient()
            {
                Host = "smtp.office365.com",
                Port = 587,
                UseDefaultCredentials = false, // This require to be before setting Credentials property
                DeliveryMethod = SmtpDeliveryMethod.Network,
                Credentials = new NetworkCredential("[email protected]", "password"), // you must give a full email address for authentication 
                TargetName = "STARTTLS/smtp.office365.com", // Set to avoid MustIssueStartTlsFirst exception
                EnableSsl = true // Set to avoid secure connection exception
            })
            {

                MailMessage message = new MailMessage()
                {
                    From = new MailAddress("[email protected]"), // sender must be a full email address
                    Subject = subject,
                    IsBodyHtml = true,
                    Body = "<h1>Hello World</h1>",
                    BodyEncoding = System.Text.Encoding.UTF8,
                    SubjectEncoding = System.Text.Encoding.UTF8,

                };
                var toAddresses = recipients.Split(',');
                foreach (var to in toAddresses)
                {
                    message.To.Add(to.Trim());
                }

                try
                {
                    client.Send(message);
                }
                catch (Exception ex)
                {
                    Debug.WriteLine(ex.Message);
                }
            }

Check play state of AVPlayer

player.timeControlStatus == AVPlayer.TimeControlStatus.playing

Facebook share button and custom text

You have several options:

  1. Use the standard FB Share button and set text via Open Graph API and meta tags on your page.
  2. Instead of Share, use FB.ui's stream.publish method, which let's you control the URL, title, caption, description and thumbnail at run-time.
  3. Or use http://www.facebook.com/sharer.php with appropriate parameters.

Get specific object by id from array of objects in AngularJS

If you can, design your JSON data structure by making use of the array indexes as IDs. You can even "normalize" your JSON arrays as long as you've no problem making use of the array indexes as "primary key" and "foreign key", something like RDBMS. As such, in future, you can even do something like this:

function getParentById(childID) {
var parentObject = parentArray[childArray[childID].parentID];
return parentObject;
}

This is the solution "By Design". For your case, simply:

var nameToFind = results[idToQuery - 1].name;

Of course, if your ID format is something like "XX-0001" of which its array index is 0, then you can either do some string manipulation to map the ID; or else nothing can be done about that except through the iteration approach.

Select subset of columns in data.table R

To subset by column index (to avoid typing their names) you can do

dt[, .SD, .SDcols = -c(1:3, 5L)]

result seems ok

            V4          V6         V7         V8         V9       V10
 1: 0.51500037 0.919066234 0.49447244 0.19564261 0.51945102 0.7238604
 2: 0.36477648 0.828889808 0.04564637 0.20265215 0.32255945 0.4483778
 3: 0.10853112 0.601278633 0.58363636 0.47807015 0.58061000 0.2584015
 4: 0.57569100 0.228642846 0.25734995 0.79528506 0.52067802 0.6644448
 5: 0.07873759 0.840349039 0.77798153 0.48699653 0.98281006 0.4480908
 6: 0.31347303 0.670762371 0.04591664 0.03428055 0.35916057 0.1297684
 7: 0.45374290 0.957848949 0.99383496 0.43939774 0.33470618 0.9429592
 8: 0.99403107 0.009750809 0.78816609 0.34713435 0.57937680 0.9227709
 9: 0.62776909 0.400467655 0.49433474 0.81536420 0.01637135 0.4942351
10: 0.10318372 0.177712847 0.27678497 0.59554454 0.29532020 0.7117959

What exactly does += do in python?

x += 5 is not exactly the same as saying x = x + 5 in Python.

Note here:

In [1]: x = [2, 3, 4]    
In [2]: y = x    
In [3]: x += 7, 8, 9    
In [4]: x
Out[4]: [2, 3, 4, 7, 8, 9]    
In [5]: y
Out[5]: [2, 3, 4, 7, 8, 9]    
In [6]: x += [44, 55]    
In [7]: x
Out[7]: [2, 3, 4, 7, 8, 9, 44, 55]    
In [8]: y
Out[8]: [2, 3, 4, 7, 8, 9, 44, 55]    
In [9]: x = x + [33, 22]    
In [10]: x
Out[10]: [2, 3, 4, 7, 8, 9, 44, 55, 33, 22]    
In [11]: y
Out[11]: [2, 3, 4, 7, 8, 9, 44, 55]

See for reference: Why does += behave unexpectedly on lists?

Android: How can I print a variable on eclipse console?

System.out.println and Log.d both go to LogCat, not the Console.

href="javascript:" vs. href="javascript:void(0)"

Using 'javascript:void 0' will do cause problem in IE

when you click the link, it will trigger onbeforeunload event of window !

<!doctype html>
<html>
<head>
</head>
<body>
<a href="javascript:void(0);" >Click me!</a>
<script>
window.onbeforeunload = function() {
    alert( 'oops!' );
};
</script>
</body>
</html>

How can I access Google Sheet spreadsheets only with Javascript?

edit: This was answered before the google doc's api was released. See Evan Plaice's answer and Dan Dascalescu's answer for more up-to-date information.

It looks lke you can, but it's a pain to use. It involves using the Google data API.

http://gdatatips.blogspot.com/2008/12/using-javascript-client-library-w-non.html

"The JavaScript client library has helper methods for Calendar, Contacts, Blogger, and Google Finance. However, you can use it with just about any Google Data API to access authenticated/private feeds. This example uses the DocList API."

and an example of writing a gadget that interfaces with spreadsheets: http://code.google.com/apis/spreadsheets/gadgets/

Remove blank lines with grep

It's true that the use of grep -v -e '^$' can work, however it does not remove blank lines that have 1 or more spaces in them. I found the easiest and simplest answer for removing blank lines is the use of awk. The following is a modified a bit from the awk guys above:

awk 'NF' foo.txt

But since this question is for using grep I'm going to answer the following:

grep -v '^ *$' foo.txt

Note: the blank space between the ^ and *.

Or you can use the \s to represent blank space like this:

grep -v '^\s*$' foo.txt

How can I change the version of npm using nvm?

Slight variation on the above instructions, worked for me. (MacOS Sierra 10.12.6)

npm install -g [email protected]
rm /usr/local/bin/npm
ln -s ~/.npm-packages/bin/npm /usr/local/bin/npm
npm --version

Setting the default ssh key location

If you are only looking to point to a different location for you identity file, the you can modify your ~/.ssh/config file with the following entry:

IdentityFile ~/.foo/identity

man ssh_config to find other config options.

Return Type for jdbcTemplate.queryForList(sql, object, classType)

List<Conversation> conversations = **jdbcTemplate**.**queryForList**(
            **SQL_QUERY**,
            new Object[] {userId, dateFrom, dateTo});  //placeholders values

Suppose the sql query is like

SQL_QUERY = "**select** info,count(*),IF(info is null , 'DATA' , 'NO DATA') **from** table where userId=? , dateFrom=? , dateTo=?";

**HERE userId=? , dateFrom=? , dateTo=?**

the question marks are place holders

**SQL_QUERY**,
            new Object[] {userId, dateFrom, dateTo});

It will go as an object array along with the sql query

"Instantiating" a List in Java?

A List isn't a real thing in Java. It's an interface, a way of defining how an object is allowed to interact with other objects. As such, it can't ever be instantiated. An ArrayList is an implementation of the List interface, as is a linked list, and so on. Use those instead.

Adobe Acrobat Pro make all pages the same dimension

With Mac OS X and the more recent versions of Acrobat Pro, the PDF printer option does not work. What does work is doing basically the same thing in Preview App. Open the multi page file in Preview, select File>Print. In the Print dialog set your sheet size as if you are using a printer. You may want to select "Auto Rotate", "Scale to Fit" and "Print Entire Image". Then in the lower left corner is the drop button "PDF" and in that menu select "Save as PDF". Give it a new file name, click Save and then you can open the resulting file in whatever PDF app you want and the sheet sizes are the same.

How do I set a path in Visual Studio?

You have a couple of options:

  • You can add the path to the DLLs to the Executable files settings under Tools > Options > Projects and Solutions > VC++ Directories (but only for building, for executing or debugging here)
  • You can add them in your global PATH environment variable
  • You can start Visual Studio using a batch file as I described here and manipulate the path in that one
  • You can copy the DLLs into the executable file's directory :-)

Applying Comic Sans Ms font style

The httpd dæmon on OpenBSD uses the following stylesheet for all of its error messages, which presumably covers all the Comic Sans variations on non-Windows systems:

http://openbsd.su/src/usr.sbin/httpd/server_http.c#server_abort_http

810    style = "body { background-color: white; color: black; font-family: "
811        "'Comic Sans MS', 'Chalkboard SE', 'Comic Neue', sans-serif; }\n"
812        "hr { border: 0; border-bottom: 1px dashed; }\n";

E.g., try this:

font-family: 'Comic Sans MS', 'Chalkboard SE', 'Comic Neue', sans-serif;

How to implement class constructor in Visual Basic?

Suppose your class is called MyStudent. Here's how you define your class constructor:

Public Class MyStudent
    Public StudentId As Integer

    'Here's the class constructor:
    Public Sub New(newStudentId As Integer)
        StudentId = newStudentId
    End Sub
End Class

Here's how you call it:

Dim student As New MyStudent(studentId)

Of course, your class constructor can contain as many or as few arguments as you need--even none, in which case you leave the parentheses empty. You can also have several constructors for the same class, all with different combinations of arguments. These are known as different "signatures" for your class constructor.

Count the cells with same color in google spreadsheet

Easy solution if you don't want to code manually using Google Sheets Power Tools:

  1. Install Power Tools through the Add-ons panel (Add-ons -> Get add-ons)
  2. From the Power Tools sidebar click on the S button and within that menu click on the "Sum by Color" menu item
  3. Select the "Pattern cell" with the color markup you want to search for
  4. Select the "Source range" for the cells you want to count
  5. Use function should be set to "COUNTA"
  6. Press "Insert function" and you're done :)

In Jinja2, how do you test if a variable is undefined?

From the Jinja2 template designer documentation:

{% if variable is defined %}
    value of variable: {{ variable }}
{% else %}
    variable is not defined
{% endif %}

Calculating how many days are between two dates in DB2?

values timestampdiff (16, char( 
    timestamp(current timestamp + 1 year + 2 month - 3 day)- 
    timestamp(current timestamp)))
1
=
422



values timestampdiff (16, char( 
    timestamp('2012-03-08-00.00.00')- 
    timestamp('2011-12-08-00.00.00')))
1
=
90

---------- EDIT BY galador

SELECT TIMESTAMPDIFF(16, CHAR(CURRENT TIMESTAMP - TIMESTAMP_FORMAT(CHDLM, 'YYYYMMDD'))
FROM CHCART00
WHERE CHSTAT = '05'

EDIT

As it has been pointed out by X-Zero, this function returns only an estimate. This is true. For accurate results I would use the following to get the difference in days between two dates a and b:

SELECT days (current date) - days (date(TIMESTAMP_FORMAT(CHDLM, 'YYYYMMDD')))
FROM CHCART00 
WHERE CHSTAT = '05';

Is it possible to style html5 audio tag?

<audio>

audio::-webkit-media-controls-panel

audio::-webkit-media-controls-mute-button

audio::-webkit-media-controls-play-button

audio::-webkit-media-controls-timeline-container

audio::-webkit-media-controls-current-time-display

audio::-webkit-media-controls-time-remaining-display

audio::-webkit-media-controls-timeline

audio::-webkit-media-controls-volume-slider-container

audio::-webkit-media-controls-volume-slider

audio::-webkit-media-controls-seek-back-button

audio::-webkit-media-controls-seek-forward-button

audio::-webkit-media-controls-fullscreen-button

audio::-webkit-media-controls-rewind-button

audio::-webkit-media-controls-return-to-realtime-button

audio::-webkit-media-controls-toggle-closed-captions-button

REFERENCE: https://chromium.googlesource.com/chromium/blink/+/72fef91ac1ef679207f51def8133b336a6f6588f/Source/core/css/mediaControls.css?autodive=0%2F%2F%2F

How to edit HTML input value colour?

You can add color in the style rule of your input: color:#ccc;

Java, Check if integer is multiple of a number

Use modulo

whenever a number x is a multiple of some number y, then always x % y equal to 0, which can be used as a check. So use

if (j % 4 == 0) 

How do I correctly upgrade angular 2 (npm) to the latest version?

Upgrade to latest Angular 5

Angular Dep packages: npm install @angular/{animations,common,compiler,core,forms,http,platform-browser,platform-browser-dynamic,router}@latest --save

Other packages that are installed by the angular cli npm install --save core-js@latest rxjs@latest zone.js@latest

Angular Dev packages: npm install --save-dev @angular/{compiler-cli,cli,language-service}@latest

Types Dev packages: npm install --save-dev @types/{jasmine,jasminewd2,node}@latest

Other packages that are installed as dev dev by the angular cli: npm install --save-dev codelyzer@latest jasmine-core@latest jasmine-spec-reporter@latest karma@latest karma-chrome-launcher@latest karma-cli@latest karma-coverage-istanbul-reporter@latest karma-jasmine@latest karma-jasmine-html-reporter@latest protractor@latest ts-node@latest tslint@latest

Install the latest supported version used by the Angular cli (don't do @latest): npm install --save-dev [email protected]

Rename file angular-cli.json to .angular-cli.json and update the content:

{
  "$schema": "./node_modules/@angular/cli/lib/config/schema.json",
  "project": {
    "name": "project3-example"
  },
  "apps": [
    {
      "root": "src",
      "outDir": "dist",
      "assets": [
        "assets",
        "favicon.ico"
      ],
      "index": "index.html",
      "main": "main.ts",
      "polyfills": "polyfills.ts",
      "test": "test.ts",
      "tsconfig": "tsconfig.app.json",
      "testTsconfig": "tsconfig.spec.json",
      "prefix": "app",
      "styles": [
        "styles.css"
      ],
      "scripts": [],
      "environmentSource": "environments/environment.ts",
      "environments": {
        "dev": "environments/environment.ts",
        "prod": "environments/environment.prod.ts"
      }
    }
  ],
  "e2e": {
    "protractor": {
      "config": "./protractor.conf.js"
    }
  },
  "lint": [
    {
      "project": "src/tsconfig.app.json",
      "exclude": "**/node_modules/**"
    },
    {
      "project": "src/tsconfig.spec.json",
      "exclude": "**/node_modules/**"
    },
    {
      "project": "e2e/tsconfig.e2e.json",
      "exclude": "**/node_modules/**"
    }
  ],
  "test": {
    "karma": {
      "config": "./karma.conf.js"
    }
  },
  "defaults": {
    "styleExt": "css",
    "component": {}
  }
}

How can I pass a list as a command-line argument with argparse?

In add_argument(), type is just a callable object that receives string and returns option value.

import ast

def arg_as_list(s):                                                            
    v = ast.literal_eval(s)                                                    
    if type(v) is not list:                                                    
        raise argparse.ArgumentTypeError("Argument \"%s\" is not a list" % (s))
    return v                                                                   


def foo():
    parser.add_argument("--list", type=arg_as_list, default=[],
                        help="List of values")

This will allow to:

$ ./tool --list "[1,2,3,4]"

How to get a list of installed android applications and pick one to run

Here's a cleaner way using the PackageManager

final PackageManager pm = getPackageManager();
//get a list of installed apps.
List<ApplicationInfo> packages = pm.getInstalledApplications(PackageManager.GET_META_DATA);

for (ApplicationInfo packageInfo : packages) {
    Log.d(TAG, "Installed package :" + packageInfo.packageName);
    Log.d(TAG, "Source dir : " + packageInfo.sourceDir);
    Log.d(TAG, "Launch Activity :" + pm.getLaunchIntentForPackage(packageInfo.packageName)); 
}
// the getLaunchIntentForPackage returns an intent that you can use with startActivity() 

More info here http://qtcstation.com/2011/02/how-to-launch-another-app-from-your-app/

Which data structures and algorithms book should I buy?

If you don't need in a complete reference to the most part of algorithms and data structures that are in use and just want to get acquainted with common techniques I would recommend something more lightweight than Cormen, Sedgewick or Knuth. I think, Algorithms and Data Structures by N. Wirth is not as bad choice even in spite of it was printed far ago.

How to get the file path from URI?

File myFile = new File(uri.toString());
myFile.getAbsolutePath()

should return u the correct path

EDIT

As @Tron suggested the working code is

File myFile = new File(uri.getPath());
myFile.getAbsolutePath()

How to plot an array in python?

if you give a 2D array to the plot function of matplotlib it will assume the columns to be lines:

If x and/or y is 2-dimensional, then the corresponding columns will be plotted.

In your case your shape is not accepted (100, 1, 1, 8000). As so you can using numpy squeeze to solve the problem quickly:

np.squeez doc: Remove single-dimensional entries from the shape of an array.

import numpy as np
import matplotlib.pyplot as plt

data = np.random.randint(3, 7, (10, 1, 1, 80))
newdata = np.squeeze(data) # Shape is now: (10, 80)
plt.plot(newdata) # plotting by columns
plt.show()

But notice that 100 sets of 80 000 points is a lot of data for matplotlib. I would recommend that you look for an alternative. The result of the code example (run in Jupyter) is:

Jupyter matplotlib plot

Fastest method to replace all instances of a character in a string

I just coded a benchmark and tested the first 3 answers. It seems that for short strings (<500 characters)
the third most voted answer is faster than the second most voted one.

For long strings (add ".repeat(300)" to the test string) the faster is answer 1 followed by the second and the third.

Note:

The above is true for browsers using v8 engine (chrome/chromium etc).
With firefox (SpiderMonkey engine) the results are totally different
Check for yourselves!! Firefox with the third solution seems to be
more than 4.5 times faster than Chrome with the first solution... crazy :D

_x000D_
_x000D_
function log(data) {_x000D_
  document.getElementById("log").textContent += data + "\n";_x000D_
}_x000D_
_x000D_
benchmark = (() => {_x000D_
_x000D_
  time_function = function(ms, f, num) {_x000D_
    var z;_x000D_
    var t = new Date().getTime();_x000D_
    for (z = 0;_x000D_
      ((new Date().getTime() - t) < ms); z++) f(num);_x000D_
    return (z / ms)_x000D_
  } // returns how many times the function was run in "ms" milliseconds._x000D_
_x000D_
_x000D_
  function benchmark() {_x000D_
    function compare(a, b) {_x000D_
      if (a[1] > b[1]) {_x000D_
        return -1;_x000D_
      }_x000D_
      if (a[1] < b[1]) {_x000D_
        return 1;_x000D_
      }_x000D_
      return 0;_x000D_
    }_x000D_
_x000D_
    // functions_x000D_
_x000D_
    function replace1(s) {_x000D_
      s.replace(/foo/g, "bar")_x000D_
    }_x000D_
_x000D_
String.prototype.replaceAll2 = function(_f, _r){ _x000D_
_x000D_
  var o = this.toString();_x000D_
  var r = '';_x000D_
  var s = o;_x000D_
  var b = 0;_x000D_
  var e = -1;_x000D_
//      if(_c){ _f = _f.toLowerCase(); s = o.toLowerCase(); }_x000D_
_x000D_
  while((e=s.indexOf(_f)) > -1)_x000D_
  {_x000D_
    r += o.substring(b, b+e) + _r;_x000D_
    s = s.substring(e+_f.length, s.length);_x000D_
    b += e+_f.length;_x000D_
  }_x000D_
_x000D_
  // Add Leftover_x000D_
  if(s.length>0){ r+=o.substring(o.length-s.length, o.length); }_x000D_
_x000D_
  // Return New String_x000D_
  return r;_x000D_
};_x000D_
_x000D_
String.prototype.replaceAll = function(str1, str2, ignore) {_x000D_
      return this.replace(new RegExp(str1.replace(/([\/\,\!\\\^\$\{\}\[\]\(\)\.\*\+\?\|\<\>\-\&])/g, "\\$&"), (ignore ? "gi" : "g")), (typeof(str2) == "string") ? str2.replace(/\$/g, "$$$$") : str2);_x000D_
    }_x000D_
_x000D_
    function replace2(s) {_x000D_
      s.replaceAll("foo", "bar")_x000D_
    }_x000D_
_x000D_
    function replace3(s) {_x000D_
      s.split('foo').join('bar');_x000D_
    }_x000D_
_x000D_
    function replace4(s) {_x000D_
      s.replaceAll2("foo", "bar")_x000D_
    }_x000D_
_x000D_
_x000D_
    funcs = [_x000D_
      [replace1, 0],_x000D_
      [replace2, 0],_x000D_
      [replace3, 0],_x000D_
      [replace4, 0]_x000D_
    ];_x000D_
_x000D_
    funcs.forEach((ff) => {_x000D_
      console.log("Benchmarking: " + ff[0].name);_x000D_
      ff[1] = time_function(2500, ff[0], "foOfoobarBaR barbarfoobarf00".repeat(10));_x000D_
      console.log("Score: " + ff[1]);_x000D_
_x000D_
    })_x000D_
    return funcs.sort(compare);_x000D_
  }_x000D_
_x000D_
  return benchmark;_x000D_
})()_x000D_
log("Starting benchmark...\n");_x000D_
res = benchmark();_x000D_
console.log("Winner: " + res[0][0].name + " !!!");_x000D_
count = 1;_x000D_
res.forEach((r) => {_x000D_
  log((count++) + ". " + r[0].name + " score: " + Math.floor(10000 * r[1] / res[0][1]) / 100 + ((count == 2) ? "% *winner*" : "% speed of winner.") + " (" + Math.round(r[1] * 100) / 100 + ")");_x000D_
});_x000D_
log("\nWinner code:\n");_x000D_
log(res[0][0].toString());
_x000D_
<textarea rows="50" cols="80" style="font-size: 16; resize:none; border: none;" id="log"></textarea>
_x000D_
_x000D_
_x000D_

The test will run for 10s (+2s) as you click the button.

My results (on the same pc):

Chrome/Linux Ubuntu 64:
1. replace1 score: 100% *winner* (766.18)
2. replace4 score: 99.07% speed of winner. (759.11)
3. replace3 score: 68.36% speed of winner. (523.83)
4. replace2 score: 59.35% speed of winner. (454.78)

Firefox/Linux Ubuntu 64
1. replace3 score: 100% *winner* (3480.1)
2. replace1 score: 13.06% speed of winner. (454.83)
3. replace4 score: 9.4% speed of winner. (327.42)
4. replace2 score: 4.81% speed of winner. (167.46)

Nice mess uh?

Took the liberty of adding more test results

Chrome/Windows 10
1. replace1 score: 100% *winner* (742.49)
2. replace4 score: 85.58% speed of winner. (635.44)
3. replace2 score: 54.42% speed of winner. (404.08)
4. replace3 score: 50.06% speed of winner. (371.73)

Firefox/Windows 10
1. replace3 score: 100% *winner* (2645.18)
2. replace1 score: 30.77% speed of winner. (814.18)
3. replace4 score: 22.3% speed of winner. (589.97)
4. replace2 score: 12.51% speed of winner. (331.13)

Edge/Windows 10
1. replace1 score: 100% *winner* (1251.24)
2. replace2 score: 46.63% speed of winner. (583.47)
3. replace3 score: 44.42% speed of winner. (555.92)
4. replace4 score: 20% speed of winner. (250.28)

Chrome on Galaxy Note 4

1. replace4 score: 100% *winner* (99.82)
2. replace1 score: 91.04% speed of winner. (90.88)
3. replace3 score: 70.27% speed of winner. (70.15)
4. replace2 score: 38.25% speed of winner. (38.18)

CSS strikethrough different color from text?

Here's an approach which uses a gradient to fake the line. It works with multiline strikes and doesn't need additional DOM elements. But as it's a background gradient, it's behind the text...

del, strike {
  text-decoration: none;
  line-height: 1.4;
  background-image: -webkit-gradient(linear, left top, left bottom, from(transparent), color-stop(0.63em, transparent), color-stop(0.63em, #ff0000), color-stop(0.7em, #ff0000), color-stop(0.7em, transparent), to(transparent));
  background-image: -webkit-linear-gradient(top, transparent 0em, transparent 0.63em, #ff0000 0.63em, #ff0000 0.7em, transparent 0.7em, transparent 1.4em);
  background-image: -o-linear-gradient(top, transparent 0em, transparent 0.63em, #ff0000 0.63em, #ff0000 0.7em, transparent 0.7em, transparent 1.4em);
  background-image: linear-gradient(to bottom, transparent 0em, transparent 0.63em, #ff0000 0.63em, #ff0000 0.7em, transparent 0.7em, transparent 1.4em);
  -webkit-background-size: 1.4em 1.4em;
  background-size: 1.4em 1.4em;
  background-repeat: repeat;
}

See fiddle: http://jsfiddle.net/YSvaY/

Gradient color-stops and background size depend on line-height. (I used LESS for calculation and Autoprefixer afterwards...)

Replace line break characters with <br /> in ASP.NET MVC Razor view

Applying the DRY principle to Omar's solution, here's an HTML Helper extension:

using System.Web.Mvc;
using System.Text.RegularExpressions;

namespace System.Web.Mvc.Html {
    public static class MyHtmlHelpers {
        public static MvcHtmlString EncodedReplace(this HtmlHelper helper, string input, string pattern, string replacement) {
            return new MvcHtmlString(Regex.Replace(helper.Encode(input), pattern, replacement));
        }
    }
}

Usage (with improved regex):

@Html.EncodedReplace(Model.CommentText, "[\n\r]+", "<br />")

This also has the added benefit of putting less onus on the Razor View developer to ensure security from XSS vulnerabilities.


My concern with Jacob's solution is that rendering the line breaks with CSS breaks the HTML semantics.

Getting data posted in between two dates

$query = $this->db
              ->get_where('orders',array('order_date <='=>$first_date,'order_date >='=>$second_date))
              ->result_array();

How to detect a mobile device with JavaScript?

This is my version, quite similar to the upper one, but I think good for reference.

if (mob_url == "") {
  lt_url = desk_url;
} else if ((useragent.indexOf("iPhone") != -1 || useragent.indexOf("Android") != -1 || useragent.indexOf("Blackberry") != -1 || useragent.indexOf("Mobile") != -1) && useragent.indexOf("iPad") == -1 && mob_url != "") {
  lt_url = mob_url;
} else {
  lt_url = desk_url;
}

Cast a Double Variable to Decimal

You can cast a double to a decimal like this, without needing the M literal suffix:

double dbl = 1.2345D;
decimal dec = (decimal) dbl;

You should use the M when declaring a new literal decimal value:

decimal dec = 123.45M;

(Without the M, 123.45 is treated as a double and will not compile.)

Image height and width not working?

You have a class on your CSS that is overwriting your width and height, the class reads as such:

.postItem img {
    height: auto;
    width: 450px;
}

Remove that and your width/height properties on the img tag should work.

Generating random integer from a range

If your compiler supports C++0x and using it is an option for you, then the new standard <random> header is likely to meet your needs. It has a high quality uniform_int_distribution which will accept minimum and maximum bounds (inclusive as you need), and you can choose among various random number generators to plug into that distribution.

Here is code that generates a million random ints uniformly distributed in [-57, 365]. I've used the new std <chrono> facilities to time it as you mentioned performance is a major concern for you.

#include <iostream>
#include <random>
#include <chrono>

int main()
{
    typedef std::chrono::high_resolution_clock Clock;
    typedef std::chrono::duration<double> sec;
    Clock::time_point t0 = Clock::now();
    const int N = 10000000;
    typedef std::minstd_rand G;
    G g;
    typedef std::uniform_int_distribution<> D;
    D d(-57, 365);
    int c = 0;
    for (int i = 0; i < N; ++i) 
        c += d(g);
    Clock::time_point t1 = Clock::now();
    std::cout << N/sec(t1-t0).count() << " random numbers per second.\n";
    return c;
}

For me (2.8 GHz Intel Core i5) this prints out:

2.10268e+07 random numbers per second.

You can seed the generator by passing in an int to its constructor:

    G g(seed);

If you later find that int doesn't cover the range you need for your distribution, this can be remedied by changing the uniform_int_distribution like so (e.g. to long long):

    typedef std::uniform_int_distribution<long long> D;

If you later find that the minstd_rand isn't a high enough quality generator, that can also easily be swapped out. E.g.:

    typedef std::mt19937 G;  // Now using mersenne_twister_engine

Having separate control over the random number generator, and the random distribution can be quite liberating.

I've also computed (not shown) the first 4 "moments" of this distribution (using minstd_rand) and compared them to the theoretical values in an attempt to quantify the quality of the distribution:

min = -57
max = 365
mean = 154.131
x_mean = 154
var = 14931.9
x_var = 14910.7
skew = -0.00197375
x_skew = 0
kurtosis = -1.20129
x_kurtosis = -1.20001

(The x_ prefix refers to "expected")

Call a global variable inside module

Sohnee solutions is cleaner, but you can also try

window["bootbox"]

Adding quotes to a string in VBScript

You have to use double double quotes to escape the double quotes (lol):

g = "abcd """ & a & """"

Conditionally formatting cells if their value equals any value of another column

No formulas required. This works on as many columns as you need, but will only compare columns in the same worksheet:

NOTE: remove any duplicates from the individual columns first!

  1. Select the columns to compare
  2. click Conditional Formatting
  3. click Highlight Cells Rules
  4. click Duplicate Values (the defaults should be OK)
  5. Duplicates are now highlighted in red

    • Bonus tip, you can filter each row by colour to either leave the unique values in the column, or leave just the duplicates.

enter image description here enter image description here

How do you remove all the options of a select box and then add one option and select it with jQuery?

Uses the jquery prop() to clear the selected option

$('#mySelect option:selected').prop('selected', false);

Install a Windows service using a Windows command prompt?

when your assembly version and your Visual studio project Biuld setting on dot net 2 or 4 install with same version.

install service with installutil that same version

if build in dot net 4

Type c:\windows\microsoft.net\framework\v4.0.30319\installutil.exe

if build in dot net 2

Type c:\windows\microsoft.net\framework\v2.0.11319\installutil.exe

Trouble Connecting to sql server Login failed. "The login is from an untrusted domain and cannot be used with Windows authentication"

If you using windows authentication make sure that password of the user hasn't expired. An expired password can explain this error. This was the problem in my case.

Get a filtered list of files in a directory

Another option:

>>> import os, fnmatch
>>> fnmatch.filter(os.listdir('.'), '*.py')
['manage.py']

https://docs.python.org/3/library/fnmatch.html

how to display a div triggered by onclick event

Here you go:

div{
    display: none;
}

document.querySelector("button").addEventListener("click", function(){
    document.querySelector("div").style.display = "block";
});

<div>blah blah blah</div>
<button>Show</button>

LIVE DEMO: http://jsfiddle.net/DerekL/p78Qq/

Drawing an image from a data URL to a canvas

function drawDataURIOnCanvas(strDataURI, canvas) {
    "use strict";
    var img = new window.Image();
    img.addEventListener("load", function () {
        canvas.getContext("2d").drawImage(img, 0, 0);
    });
    img.setAttribute("src", strDataURI);
}

initialize a numpy array

Introduced in numpy 1.8:

numpy.full

Return a new array of given shape and type, filled with fill_value.

Examples:

>>> import numpy as np
>>> np.full((2, 2), np.inf)
array([[ inf,  inf],
       [ inf,  inf]])
>>> np.full((2, 2), 10)
array([[10, 10],
       [10, 10]])

Sorting 1 million 8-decimal-digit numbers with 1 MB of RAM

I would exploit the retransmission behaviour of TCP.

  1. Make the TCP component create a large receive window.
  2. Receive some amount of packets without sending an ACK for them.
    • Process those in passes creating some (prefix) compressed data structure
    • Send duplicate ack for last packet that is not needed anymore/wait for retransmission timeout
    • Goto 2
  3. All packets were accepted

This assumes some kind of benefit of buckets or multiple passes.

Probably by sorting the batches/buckets and merging them. -> radix trees

Use this technique to accept and sort the first 80% then read the last 20%, verify that the last 20% do not contain numbers that would land in the first 20% of the lowest numbers. Then send the 20% lowest numbers, remove from memory, accept the remaining 20% of new numbers and merge.**

What does "while True" mean in Python?

while True mean infinite loop, this usually use by long process. you can change

while True:

with

while 1:

What is std::move(), and when should it be used?

Q: What is std::move?

A: std::move() is a function from the C++ Standard Library for casting to a rvalue reference.

Simplisticly std::move(t) is equivalent to:

static_cast<T&&>(t);

An rvalue is a temporary that does not persist beyond the expression that defines it, such as an intermediate function result which is never stored in a variable.

int a = 3; // 3 is a rvalue, does not exist after expression is evaluated
int b = a; // a is a lvalue, keeps existing after expression is evaluated

An implementation for std::move() is given in N2027: "A Brief Introduction to Rvalue References" as follows:

template <class T>
typename remove_reference<T>::type&&
std::move(T&& a)
{
    return a;
}

As you can see, std::move returns T&& no matter if called with a value (T), reference type (T&), or rvalue reference (T&&).

Q: What does it do?

A: As a cast, it does not do anything during runtime. It is only relevant at compile time to tell the compiler that you would like to continue considering the reference as an rvalue.

foo(3 * 5); // obviously, you are calling foo with a temporary (rvalue)

int a = 3 * 5;
foo(a);     // how to tell the compiler to treat `a` as an rvalue?
foo(std::move(a)); // will call `foo(int&& a)` rather than `foo(int a)` or `foo(int& a)`

What it does not do:

  • Make a copy of the argument
  • Call the copy constructor
  • Change the argument object

Q: When should it be used?

A: You should use std::move if you want to call functions that support move semantics with an argument which is not an rvalue (temporary expression).

This begs the following follow-up questions for me:

  • What is move semantics? Move semantics in contrast to copy semantics is a programming technique in which the members of an object are initialized by 'taking over' instead of copying another object's members. Such 'take over' makes only sense with pointers and resource handles, which can be cheaply transferred by copying the pointer or integer handle rather than the underlying data.

  • What kind of classes and objects support move semantics? It is up to you as a developer to implement move semantics in your own classes if these would benefit from transferring their members instead of copying them. Once you implement move semantics, you will directly benefit from work from many library programmers who have added support for handling classes with move semantics efficiently.

  • Why can't the compiler figure it out on its own? The compiler cannot just call another overload of a function unless you say so. You must help the compiler choose whether the regular or move version of the function should be called.

  • In which situations would I want to tell the compiler that it should treat a variable as an rvalue? This will most likely happen in template or library functions, where you know that an intermediate result could be salvaged.

jQuery trigger file input

This is probably the best answer, keeping in mind the cross browser issues.

CSS:

#file {
  opacity: 0;
  width: 1px;
  height: 1px;
}

JS:

$(".file-upload").on('click',function(){
   $("[name='file']").click();
});

HTML:

<a class="file-upload">Upload</a>
<input type="file" name="file">

Saving awk output to variable

I think the $() syntax is easier to read...

variable=$(ps -ef | grep "port 10 -" | grep -v "grep port 10 -"| awk '{printf "%s", $12}')

But the real issue is probably that $12 should not be qouted with ""

Edited since the question was changed, This returns valid data, but it is not clear what the expected output of ps -ef is and what is expected in variable.

In Bootstrap 3,How to change the distance between rows in vertical?

UPDATE

Bootstrap 4 has spacing utilities to handle this https://getbootstrap.com/docs/4.0/utilities/spacing/

.mt-0 {
  margin-top: 0 !important;
}

--

ORIGINAL ANSWER

If you are using SASS, this is what I normally do.

$margins: (xs: 0.5rem, sm: 1rem, md: 1.5rem, lg: 2rem, xl: 2.5rem);

@each $name, $value in $margins {
  .margin-top-#{$name} {
    margin-top: $value;
  }

  .margin-bottom-#{$name} {
    margin-bottom: $value;
  }
}

so you can later use margin-top-xs for example

Make Https call using HttpClient

When connect to https I got this error too, I add this line before HttpClient httpClient = new HttpClient(); and connect successfully:

ServicePointManager.ServerCertificateValidationCallback = delegate { return true; };

I know it from This Answer and Another Similar Anwser and the comment mentions:

This is a hack useful in development so putting a #if DEBUG #endif statement around it is the least you should do to make this safer and stop this ending up in production

Besides, I didn't try the method in Another Answer that use new X509Certificate() or new X509Certificate2() to make a Certificate, I'm not sure simply create by new() will work or not.

EDIT: Some References:

Create a Self-Signed Server Certificate in IIS 7

Import and Export SSL Certificates in IIS 7

Convert .pfx to .cer

Best practices for using ServerCertificateValidationCallback

I find value of Thumbprint is equal to x509certificate.GetCertHashString():

Retrieve the Thumbprint of a Certificate

SQL Query To Obtain Value that Occurs more than once

From Oracle (but works in most SQL DBs):

SELECT LASTNAME, COUNT(*)
FROM STUDENTS
GROUP BY LASTNAME
HAVING COUNT(*) >= 3

P.S. it's faster one, because you have no Select withing Select methods here

When is TCP option SO_LINGER (0) required?

I like Maxim's observation that DOS attacks can exhaust server resources. It also happens without an actually malicious adversary.

Some servers have to deal with the 'unintentional DOS attack' which occurs when the client app has a bug with connection leak, where they keep creating a new connection for every new command they send to your server. And then perhaps eventually closing their connections if they hit GC pressure, or perhaps the connections eventually time out.

Another scenario is when 'all clients have the same TCP address' scenario. Then client connections are distinguishable only by port numbers (if they connect to a single server). And if clients start rapidly cycling opening/closing connections for any reason they can exhaust the (client addr+port, server IP+port) tuple-space.

So I think servers may be best advised to switch to the Linger-Zero strategy when they see a high number of sockets in the TIME_WAIT state - although it doesn't fix the client behavior, it might reduce the impact.

How to align title at center of ActionBar in default theme(Theme.Holo.Light)

solution is based on these things:

  • you need to use your own class that extends Toolbar (support.v7.widget.toolbar)
  • you need to override one method Toolbar#addView

what does it do:

when first time toolbar is executing #setTitle, it creates AppCompatTextView and uses it to display title text.

when the AppCompatTextView is created, toolbar (as ViewGroup), adds it into it's own hierarchy with #addView method.

also, while trying to find solution i noticed that the textview has layout width set to "wrap_content", so i decided to make it "match_parent" and assign textalignment to "center".

MyToolbar.kt, skipping unrelated stuff (constructors/imports):

class MyToolbar : Toolbar {

  override fun addView(child: View, params: ViewGroup.LayoutParams) {
    if (child is TextView) {
        params.width = ViewGroup.LayoutParams.MATCH_PARENT
        child.textAlignment= View.TEXT_ALIGNMENT_CENTER
    }
    super.addView(child, params)
  }
}

possible "side effects" - this will apply to "subtitle" too

Converting date between DD/MM/YYYY and YYYY-MM-DD?

you first would need to convert string into datetime tuple, and then convert that datetime tuple to string, it would go like this:

lastconnection = datetime.strptime("21/12/2008", "%d/%m/%Y").strftime('%Y-%m-%d')

How do you test that a Python function throws an exception?

I just discovered that the Mock library provides an assertRaisesWithMessage() method (in its unittest.TestCase subclass), which will check not only that the expected exception is raised, but also that it is raised with the expected message:

from testcase import TestCase

import mymod

class MyTestCase(TestCase):
    def test1(self):
        self.assertRaisesWithMessage(SomeCoolException,
                                     'expected message',
                                     mymod.myfunc)

How can I convert JSON to a HashMap using Gson?

I used this code:

Gson gson = new Gson();
HashMap<String, Object> fields = gson.fromJson(json, HashMap.class);

Checking for Undefined In React

In case you also need to check if nextProps.blog is not undefined ; you can do that in a single if statement, like this:

if (typeof nextProps.blog !== "undefined" && typeof nextProps.blog.content !== "undefined") {
    //
}

And, when an undefined , empty or null value is not expected; you can make it more concise:

if (nextProps.blog && nextProps.blog.content) {
    //
}

Catch a thread's exception in the caller thread in Python

If an exception occurs in a thread, the best way is to re-raise it in the caller thread during join. You can get information about the exception currently being handled using the sys.exc_info() function. This information can simply be stored as a property of the thread object until join is called, at which point it can be re-raised.

Note that a Queue.Queue (as suggested in other answers) is not necessary in this simple case where the thread throws at most 1 exception and completes right after throwing an exception. We avoid race conditions by simply waiting for the thread to complete.

For example, extend ExcThread (below), overriding excRun (instead of run).

Python 2.x:

import threading

class ExcThread(threading.Thread):
  def excRun(self):
    pass

  def run(self):
    self.exc = None
    try:
      # Possibly throws an exception
      self.excRun()
    except:
      import sys
      self.exc = sys.exc_info()
      # Save details of the exception thrown but don't rethrow,
      # just complete the function

  def join(self):
    threading.Thread.join(self)
    if self.exc:
      msg = "Thread '%s' threw an exception: %s" % (self.getName(), self.exc[1])
      new_exc = Exception(msg)
      raise new_exc.__class__, new_exc, self.exc[2]

Python 3.x:

The 3 argument form for raise is gone in Python 3, so change the last line to:

raise new_exc.with_traceback(self.exc[2])

Is there an SQLite equivalent to MySQL's DESCRIBE [table]?

The SQLite command line utility has a .schema TABLENAME command that shows you the create statements.

How to list files using dos commands?

Try dir /b, for bare format.

dir /? will show you documentation of what you can do with the dir command. Here is the output from my Windows 7 machine:

C:\>dir /?
Displays a list of files and subdirectories in a directory.

DIR [drive:][path][filename] [/A[[:]attributes]] [/B] [/C] [/D] [/L] [/N]
  [/O[[:]sortorder]] [/P] [/Q] [/R] [/S] [/T[[:]timefield]] [/W] [/X] [/4]

  [drive:][path][filename]
              Specifies drive, directory, and/or files to list.

  /A          Displays files with specified attributes.
  attributes   D  Directories                R  Read-only files
               H  Hidden files               A  Files ready for archiving
               S  System files               I  Not content indexed files
               L  Reparse Points             -  Prefix meaning not
  /B          Uses bare format (no heading information or summary).
  /C          Display the thousand separator in file sizes.  This is the
              default.  Use /-C to disable display of separator.
  /D          Same as wide but files are list sorted by column.
  /L          Uses lowercase.
  /N          New long list format where filenames are on the far right.
  /O          List by files in sorted order.
  sortorder    N  By name (alphabetic)       S  By size (smallest first)
               E  By extension (alphabetic)  D  By date/time (oldest first)
               G  Group directories first    -  Prefix to reverse order
  /P          Pauses after each screenful of information.
  /Q          Display the owner of the file.
  /R          Display alternate data streams of the file.
  /S          Displays files in specified directory and all subdirectories.
  /T          Controls which time field displayed or used for sorting
  timefield   C  Creation
              A  Last Access
              W  Last Written
  /W          Uses wide list format.
  /X          This displays the short names generated for non-8dot3 file
              names.  The format is that of /N with the short name inserted
              before the long name. If no short name is present, blanks are
              displayed in its place.
  /4          Displays four-digit years

Switches may be preset in the DIRCMD environment variable.  Override
preset switches by prefixing any switch with - (hyphen)--for example, /-W.

How to tell Jackson to ignore a field during serialization if its value is null?

To suppress serializing properties with null values using Jackson >2.0, you can configure the ObjectMapper directly, or make use of the @JsonInclude annotation:

mapper.setSerializationInclusion(Include.NON_NULL);

or:

@JsonInclude(Include.NON_NULL)
class Foo
{
  String bar;
}

Alternatively, you could use @JsonInclude in a getter so that the attribute would be shown if the value is not null.

A more complete example is available in my answer to How to prevent null values inside a Map and null fields inside a bean from getting serialized through Jackson.

Java to Jackson JSON serialization: Money fields

Instead of setting the @JsonSerialize on each member or getter you can configure a module that use a custome serializer for a certain type:

SimpleModule module = new SimpleModule();
module.addSerializer(BigInteger.class, new ToStringSerializer());
objectMapper.registerModule(module);

In the above example, I used the to string serializer to serialize BigIntegers (since javascript can not handle such numeric values).

How to programmatically take a screenshot on Android?

Take screenshot of a view in android.

public static Bitmap getViewBitmap(View v) {
    v.clearFocus();
    v.setPressed(false);

    boolean willNotCache = v.willNotCacheDrawing();
    v.setWillNotCacheDrawing(false);

    int color = v.getDrawingCacheBackgroundColor();
    v.setDrawingCacheBackgroundColor(0);

    if (color != 0) {
        v.destroyDrawingCache();
    }
    v.buildDrawingCache();
    Bitmap cacheBitmap = v.getDrawingCache();
    if (cacheBitmap == null) {
        return null;
    }

    Bitmap bitmap = Bitmap.createBitmap(cacheBitmap);

    v.destroyDrawingCache();
    v.setWillNotCacheDrawing(willNotCache);
    v.setDrawingCacheBackgroundColor(color);

    return bitmap;
}

Cannot access mongodb through browser - It looks like you are trying to access MongoDB over HTTP on the native driver port

MongoDB has a simple web based administrative port at 28017 by default.

There is no HTTP access at the default port of 27017 (which is what the error message is trying to suggest). The default port is used for native driver access, not HTTP traffic.

To access MongoDB, you'll need to use a driver like the MongoDB native driver for NodeJS. You won't "POST" to MongoDB directly (but you might create a RESTful API using express which uses the native drivers). Instead, you'll use a wrapper library that makes accessing MongoDB convenient. You might also consider using Mongoose (which uses the native driver) which adds an ORM-like model for MongoDB in NodeJS.

If you can't get to the web interface, it may be disabled. Normally, I wouldn't expect that you'd need it for doing development unless you're checking logs and such.

How to convert a date to milliseconds

tl;dr

LocalDateTime.parse(           // Parse into an object representing a date with a time-of-day but without time zone and without offset-from-UTC.
    "2014/10/29 18:10:45"      // Convert input string to comply with standard ISO 8601 format.
    .replace( " " , "T" )      // Replace SPACE in the middle with a `T`.
    .replace( "/" , "-" )      // Replace SLASH in the middle with a `-`.
)
.atZone(                       // Apply a time zone to provide the context needed to determine an actual moment.
    ZoneId.of( "Europe/Oslo" ) // Specify the time zone you are certain was intended for that input.
)                              // Returns a `ZonedDateTime` object.
.toInstant()                   // Adjust into UTC.
.toEpochMilli()                // Get the number of milliseconds since first moment of 1970 in UTC, 1970-01-01T00:00Z.

1414602645000

Time Zone

The accepted answer is correct, except that it ignores the crucial issue of time zone. Is your input string 6:10 PM in Paris or Montréal? Or UTC?

Use a proper time zone name. Usually a continent plus city/region. For example, "Europe/Oslo". Avoid the 3 or 4 letter codes which are neither standardized nor unique.

java.time

The modern approach uses the java.time classes.

Alter your input to conform with the ISO 8601 standard. Replace the SPACE in the middle with a T. And replace the slash characters with hyphens. The java.time classes use these standard formats by default when parsing/generating strings. So no need to specify a formatting pattern.

String input = "2014/10/29 18:10:45".replace( " " , "T" ).replace( "/" , "-" ) ;
LocalDateTime ldt = LocalDateTime.parse( input ) ;

A LocalDateTime, like your input string, lacks any concept of time zone or offset-from-UTC. Without the context of a zone/offset, a LocalDateTime has no real meaning. Is it 6:10 PM in India, Europe, or Canada? Each of those places experience 6:10 PM at different moments, at different points on the timeline. So you must specify which you have in mind if you want to determine a specific point on the timeline.

ZoneId z = ZoneId.of( "Europe/Oslo" ) ;
ZonedDateTime zdt = ldt.atZone( z ) ;  

Now we have a specific moment, in that ZonedDateTime. Convert to UTC by extracting a Instant. The Instant class represents a moment on the timeline in UTC with a resolution of nanoseconds (up to nine (9) digits of a decimal fraction).

Instant instant = zdt.toInstant() ;

Now we can get your desired count of milliseconds since the epoch reference of first moment of 1970 in UTC, 1970-01-01T00:00Z.

long millisSinceEpoch = instant.toEpochMilli() ; 

Be aware of possible data loss. The Instant object is capable of carrying microseconds or nanoseconds, finer than milliseconds. That finer fractional part of a second will be ignored when getting a count of milliseconds.


About java.time

The java.time framework is built into Java 8 and later. These classes supplant the troublesome old legacy date-time classes such as java.util.Date, Calendar, & SimpleDateFormat.

The Joda-Time project, now in maintenance mode, advises migration to the java.time classes.

To learn more, see the Oracle Tutorial. And search Stack Overflow for many examples and explanations. Specification is JSR 310.

You may exchange java.time objects directly with your database. Use a JDBC driver compliant with JDBC 4.2 or later. No need for strings, no need for java.sql.* classes.

Where to obtain the java.time classes?

The ThreeTen-Extra project extends java.time with additional classes. This project is a proving ground for possible future additions to java.time. You may find some useful classes here such as Interval, YearWeek, YearQuarter, and more.


Joda-Time

Update: The Joda-Time project is now in maintenance mode, with the team advising migration to the java.time classes. I will leave this section intact for history.

Below is the same kind of code but using the Joda-Time 2.5 library and handling time zone.

The java.util.Date, .Calendar, and .SimpleDateFormat classes are notoriously troublesome, confusing, and flawed. Avoid them. Use either Joda-Time or the java.time package (inspired by Joda-Time) built into Java 8.

ISO 8601

Your string is almost in ISO 8601 format. The slashes need to be hyphens and the SPACE in middle should be replaced with a T. If we tweak that, then the resulting string can be fed directly into constructor without bothering to specify a formatter. Joda-Time uses ISO 8701 formats as it's defaults for parsing and generating strings.

Example Code

String inputRaw = "2014/10/29 18:10:45";
String input = inputRaw.replace( "/", "-" ).replace( " ", "T" );
DateTimeZone zone = DateTimeZone.forID( "Europe/Oslo" ); // Or DateTimeZone.UTC
DateTime dateTime = new DateTime( input, zone );
long millisecondsSinceUnixEpoch = dateTime.getMillis();

Install a Nuget package in Visual Studio Code

  1. Install NuGet Package Manager
  2. Ctrl+Shift+P on Windows or Command+Shift+P on Mac
  3. Search for NuGet Package Manager: Add Package
  4. Enter package name i.e. AutoMapper
  5. Select package & version
  6. Restore if needed

Laravel 5.4 ‘cross-env’ Is Not Recognized as an Internal or External Command

First run:

rm -rf node_modules
rm package-lock.json yarn.lock
npm cache clear --force

Then run the command

npm install cross-env

npm install 

and then you can also run

npm run dev

How do I free memory in C?

You have to free() the allocated memory in exact reverse order of how it was allocated using malloc().

Note that You should free the memory only after you are done with your usage of the allocated pointers.

memory allocation for 1D arrays:

    buffer = malloc(num_items*sizeof(double));

memory deallocation for 1D arrays:

    free(buffer);

memory allocation for 2D arrays:

    double **cross_norm=(double**)malloc(150 * sizeof(double *));
    for(i=0; i<150;i++)
    {
        cross_norm[i]=(double*)malloc(num_items*sizeof(double));
    }

memory deallocation for 2D arrays:

    for(i=0; i<150;i++)
    {
        free(cross_norm[i]);
    }

    free(cross_norm);

Disable click outside of bootstrap modal area to close modal

Another option if you do not know if the modal has already been opened or not yet and you need to configure the modal options:

Bootstrap 3.4

var $modal = $('#modal');
var keyboard = false; // Prevent to close by ESC
var backdrop = 'static'; // Prevent to close on click outside the modal

if(typeof $modal.data('bs.modal') === 'undefined') { // Modal did not open yet
    $modal.modal({
        keyboard: keyboard,
        backdrop: backdrop
    });
} else { // Modal has already been opened
    $modal.data('bs.modal').options.keyboard = keyboard;
    $modal.data('bs.modal').options.backdrop = backdrop;

    if(keyboard === false) { 
        $modal.off('keydown.dismiss.bs.modal'); // Disable ESC
    } else { // 
        $modal.data('bs.modal').escape(); // Resets ESC
    }
}

Bootstrap 4.3+

var $modal = $('#modal');
var keyboard = false; // Prevent to close by ESC
var backdrop = 'static'; // Prevent to close on click outside the modal

if(typeof $modal.data('bs.modal') === 'undefined') { // Modal did not open yet
    $modal.modal({
        keyboard: keyboard,
        backdrop: backdrop
    });
} else { // Modal has already been opened
    $modal.data('bs.modal')._config.keyboard = keyboard;
    $modal.data('bs.modal')._config.backdrop = backdrop;

    if(keyboard === false) { 
        $modal.off('keydown.dismiss.bs.modal'); // Disable ESC
    } else { // 
        $modal.data('bs.modal').escape(); // Resets ESC
    }
}

Change options to _config

WebSockets protocol vs HTTP

For the TL;DR, here are 2 cents and a simpler version for your questions:

  1. WebSockets provides these benefits over HTTP:

    • Persistent stateful connection for the duration of the connection
    • Low latency: near-real-time communication between server/client due to no overhead of reestablishing connections for each request as HTTP requires.
    • Full duplex: both server and client can send/receive simultaneously
  2. WebSocket and HTTP protocol have been designed to solve different problems, I.E. WebSocket was designed to improve bi-directional communication whereas HTTP was designed to be stateless, distributed using a request/response model. Other than sharing the ports for legacy reasons (firewall/proxy penetration), there isn't much common ground to combine them into one protocol.

How to remove the last element added into the List?

if you need to do it more often , you can even create your own method for pop the last element; something like this:

public void pop(List<string> myList) {
    myList.RemoveAt(myList.Count - 1);
}

or even instead of void you can return the value like:

public string pop (List<string> myList) {
    // first assign the  last value to a seperate string 
    string extractedString = myList(myList.Count - 1);
    // then remove it from list
    myList.RemoveAt(myList.Count - 1);
    // then return the value 
    return extractedString;
}

just notice that the second method's return type is not void , it is string b/c we want that function to return us a string ...

The preferred way of creating a new element with jQuery

According to the documentation for 3.4, It is preferred to use attributes with attr() method.

$('<div></div>').attr(
  {
    id: 'some dynanmic|static id',
    "class": 'some dynanmic|static class'
  }
).click(function() {
  $( "span", this ).addClass( "bar" ); // example from the docs
});

c# foreach (property in object)... Is there a simple way of doing this?

Your'e almost there, you just need to get the properties from the type, rather than expect the properties to be accessible in the form of a collection or property bag:

var property in obj.GetType().GetProperties()

From there you can access like so:

property.Name
property.GetValue(obj, null)

With GetValue the second parameter will allow you to specify index values, which will work with properties returning collections - since a string is a collection of chars, you can also specify an index to return a character if needs be.

iOS - Dismiss keyboard when touching outside of UITextField

For those struggling with this in Swift. This is the accepted answer by Jensen2k but in Swift.

Swift 2.3

    override func viewDidLoad() {
        //.....

        let viewTapGestureRec = UITapGestureRecognizer(target: self, action: #selector(handleViewTap(_:)))
        //this line is important
        viewTapGestureRec.cancelsTouchesInView = false
        self.view.addGestureRecognizer(viewTapGestureRec)

         //.....
    }

    func handleViewTap(recognizer: UIGestureRecognizer) {
        myTextField.resignFirstResponder()
    }

Get underlined text with Markdown

Markdown doesn't have a defined syntax to underline text.

I guess this is because underlined text is hard to read, and that it's usually used for hyperlinks.

Change x axes scale in matplotlib

The scalar formatter supports collecting the exponents. The docs are as follows:

class matplotlib.ticker.ScalarFormatter(useOffset=True, useMathText=False, useLocale=None) Bases: matplotlib.ticker.Formatter

Tick location is a plain old number. If useOffset==True and the data range is much smaller than the data average, then an offset will be determined such that the tick labels are meaningful. Scientific notation is used for data < 10^-n or data >= 10^m, where n and m are the power limits set using set_powerlimits((n,m)). The defaults for these are controlled by the axes.formatter.limits rc parameter.

your technique would be:

from matplotlib.ticker import ScalarFormatter
xfmt = ScalarFormatter()
xfmt.set_powerlimits((-3,3))  # Or whatever your limits are . . .
{{ Make your plot }}
gca().xaxis.set_major_formatter(xfmt)

To get the exponent displayed in the format x10^5, instantiate the ScalarFormatter with useMathText=True.

After Image

You could also use:

xfmt.set_useOffset(10000)

To get a result like this:

enter image description here

How do I set GIT_SSL_NO_VERIFY for specific repos only?

If you have to disable SSL checks for one git server hosting several repositories, you can run :

git config --bool --add http.https://my.bad.server.sslverify false

This will add it to your user's configuration.

Command to check:

git config --bool --get-urlmatch http.sslverify https://my.bad.server 

(If you still use git < v1.8.5, run git config --global http.https://my.bad.server.sslVerify false)

Explanation from the documentation where the command is at the end, show the .gitconfig content looking like:

[http "https://my.bad.server"]
        sslVerify = false

It will ignore any certificate checks for this server, whatever the repository.

You also have some explanation in the code

How to Insert BOOL Value to MySQL Database

TRUE and FALSE are keywords, and should not be quoted as strings:

INSERT INTO first VALUES (NULL, 'G22', TRUE);
INSERT INTO first VALUES (NULL, 'G23', FALSE);

By quoting them as strings, MySQL will then cast them to their integer equivalent (since booleans are really just a one-byte INT in MySQL), which translates into zero for any non-numeric string. Thus, you get 0 for both values in your table.

Non-numeric strings cast to zero:

mysql> SELECT CAST('TRUE' AS SIGNED), CAST('FALSE' AS SIGNED), CAST('12345' AS SIGNED);
+------------------------+-------------------------+-------------------------+
| CAST('TRUE' AS SIGNED) | CAST('FALSE' AS SIGNED) | CAST('12345' AS SIGNED) |
+------------------------+-------------------------+-------------------------+
|                      0 |                       0 |                   12345 |
+------------------------+-------------------------+-------------------------+

But the keywords return their corresponding INT representation:

mysql> SELECT TRUE, FALSE;
+------+-------+
| TRUE | FALSE |
+------+-------+
|    1 |     0 |
+------+-------+

Note also, that I have replaced your double-quotes with single quotes as are more standard SQL string enclosures. Finally, I have replaced your empty strings for id with NULL. The empty string may issue a warning.

Difference between Static and final?

Static and final have some big differences:

Static variables or classes will always be available from (pretty much) anywhere. Final is just a keyword that means a variable cannot be changed. So if had:

public class Test{    
   public final int first = 10;
   public static int second = 20;

   public Test(){
     second = second + 1
     first = first + 1;
   }
}

The program would run until it tried to change the "first" integer, which would cause an error. Outside of this class, you would only have access to the "first" variable if you had instantiated the class. This is in contrast to "second", which is available all the time.

Where in memory are my variables stored in C?

Linux minimal runnable examples with disassembly analysis

Since this is an implementation detail not specified by standards, let's just have a look at what the compiler is doing on a particular implementation.

In this answer, I will either link to specific answers that do the analysis, or provide the analysis directly here, and summarize all results here.

All of those are in various Ubuntu / GCC versions, and the outcomes are likely pretty stable across versions, but if we find any variations let's specify more precise versions.

Local variable inside a function

Be it main or any other function:

void f(void) {
    int my_local_var;
}

As shown at: What does <value optimized out> mean in gdb?

  • -O0: stack
  • -O3: registers if they don't spill, stack otherwise

For motivation on why the stack exists see: What is the function of the push / pop instructions used on registers in x86 assembly?

Global variables and static function variables

/* BSS */
int my_global_implicit;
int my_global_implicit_explicit_0 = 0;

/* DATA */
int my_global_implicit_explicit_1 = 1;

void f(void) {
    /* BSS */
    static int my_static_local_var_implicit;
    static int my_static_local_var_explicit_0 = 0;

    /* DATA */
    static int my_static_local_var_explicit_1 = 1;
}
  • if initialized to 0 or not initialized (and therefore implicitly initialized to 0): .bss section, see also: Why is the .bss segment required?
  • otherwise: .data section

char * and char c[]

As shown at: Where are static variables stored in C and C++?

void f(void) {
    /* RODATA / TEXT */
    char *a = "abc";

    /* Stack. */
    char b[] = "abc";
    char c[] = {'a', 'b', 'c', '\0'};
}

TODO will very large string literals also be put on the stack? Or .data? Or does compilation fail?

Function arguments

void f(int i, int j);

Must go through the relevant calling convention, e.g.: https://en.wikipedia.org/wiki/X86_calling_conventions for X86, which specifies either specific registers or stack locations for each variable.

Then as shown at What does <value optimized out> mean in gdb?, -O0 then slurps everything into the stack, while -O3 tries to use registers as much as possible.

If the function gets inlined however, they are treated just like regular locals.

const

I believe that it makes no difference because you can typecast it away.

Conversely, if the compiler is able to determine that some data is never written to, it could in theory place it in .rodata even if not const.

TODO analysis.

Pointers

They are variables (that contain addresses, which are numbers), so same as all the rest :-)

malloc

The question does not make much sense for malloc, since malloc is a function, and in:

int *i = malloc(sizeof(int));

*i is a variable that contains an address, so it falls on the above case.

As for how malloc works internally, when you call it the Linux kernel marks certain addresses as writable on its internal data structures, and when they are touched by the program initially, a fault happens and the kernel enables the page tables, which lets the access happen without segfaul: How does x86 paging work?

Note however that this is basically exactly what the exec syscall does under the hood when you try to run an executable: it marks pages it wants to load to, and writes the program there, see also: How does kernel get an executable binary file running under linux? Except that exec has some extra limitations on where to load to (e.g. is the code is not relocatable).

The exact syscall used for malloc is mmap in modern 2020 implementations, and in the past brk was used: Does malloc() use brk() or mmap()?

Dynamic libraries

Basically get mmaped to memory: https://unix.stackexchange.com/questions/226524/what-system-call-is-used-to-load-libraries-in-linux/462710#462710

envinroment variables and main's argv

Above initial stack: https://unix.stackexchange.com/questions/75939/where-is-the-environment-string-actual-stored TODO why not in .data?

Getting Error "Form submission canceled because the form is not connected"

alternatively include event.preventDefault(); in your handleSubmit(event) {

see https://facebook.github.io/react/docs/forms.html

Jenkins vs Travis-CI. Which one would you use for a Open Source project?

I would suggest Travis for Open source project. It's just simple to configure and use.

Simple steps to setup:

  1. Should have GITHUB account and register in Travis CI website using your GITHUB account.
  2. Add .travis.yml file in root of your project. Add Travis as service in your repository settings page.

Now every time you commit into your repository Travis will build your project. You can follow simple steps to get started with Travis CI.

Count number of rows per group and add result to original data frame

One simple line in base R:

df$count = table(interaction(df[, (c("name", "type"))]))[interaction(df[, (c("name", "type"))])]

Same in two lines, for clarity/efficiency:

fact = interaction(df[, (c("name", "type"))])
df$count = table(fact)[fact]

How to allow only numeric (0-9) in HTML inputbox using jQuery?

Use the jquery numeric value. Below function allows for decimal and numeric values.
Example: $("#inputId").numeric({ allow: "." });

In Perl, how can I read an entire file into a string?

With File::Slurp:

use File::Slurp;
my $text = read_file('index.html');

Yes, even you can use CPAN.

How to get current user in asp.net core

It would appear that as of now (April of 2017) that the following works:

public string LoggedInUser => User.Identity.Name;

At least while within a Controller

Spring Boot: Is it possible to use external application.properties files in arbitrary directories with a fat jar?

Another flexible way using classpath containing fat jar (-cp fat.jar) or all jars (-cp "$JARS_DIR/*") and another custom config classpath or folder containing configuration files usually elsewhere and outside jar. So instead of the limited java -jar, use the more flexible classpath way as follows:

java \
   -cp fat_app.jar \ 
   -Dloader.path=<path_to_your_additional_jars or config folder> \
   org.springframework.boot.loader.PropertiesLauncher

See Spring-boot executable jar doc and this link

If you do have multiple MainApps which is common, you can use How do I tell Spring Boot which main class to use for the executable jar?

You can add additional locations by setting an environment variable LOADER_PATH or loader.path in loader.properties (comma-separated list of directories, archives, or directories within archives). Basically loader.path works for both java -jar or java -cp way.

And as always you can override and exactly specify the application.yml it should pickup for debugging purpose

--spring.config.location=/some-location/application.yml --debug

How to create a static library with g++?

Can someone please tell me how to create a static library from a .cpp and a .hpp file? Do I need to create the .o and the the .a?

Yes.

Create the .o (as per normal):

g++ -c header.cpp

Create the archive:

ar rvs header.a header.o

Test:

g++ test.cpp header.a -o executable_name

Note that it seems a bit pointless to make an archive with just one module in it. You could just as easily have written:

g++ test.cpp header.cpp -o executable_name

Still, I'll give you the benefit of the doubt that your actual use case is a bit more complex, with more modules.

Hope this helps!

Create an array of integers property in Objective-C

I'm just speculating:

I think that the variable defined in the ivars allocates the space right in the object. This prevents you from creating accessors because you can't give an array by value to a function but only through a pointer. Therefore you have to use a pointer in the ivars:

int *doubleDigits;

And then allocate the space for it in the init-method:

@synthesize doubleDigits;

- (id)init {
    if (self = [super init]) {
        doubleDigits = malloc(sizeof(int) * 10);
        /*
         * This works, but is dangerous (forbidden) because bufferDoubleDigits
         * gets deleted at the end of -(id)init because it's on the stack:
         * int bufferDoubleDigits[] = {1,2,3,4,5,6,7,8,9,10};
         * [self setDoubleDigits:bufferDoubleDigits];
         *
         * If you want to be on the safe side use memcpy() (needs #include <string.h>)
         * doubleDigits = malloc(sizeof(int) * 10);
         * int bufferDoubleDigits[] = {1,2,3,4,5,6,7,8,9,10};
         * memcpy(doubleDigits, bufferDoubleDigits, sizeof(int) * 10);
         */
    }
    return self;
}

- (void)dealloc {
    free(doubleDigits);
    [super dealloc];
}

In this case the interface looks like this:

@interface MyClass : NSObject {
    int *doubleDigits;
}
@property int *doubleDigits;

Edit:

I'm really unsure wether it's allowed to do this, are those values really on the stack or are they stored somewhere else? They are probably stored on the stack and therefore not safe to use in this context. (See the question on initializer lists)

int bufferDoubleDigits[] = {1,2,3,4,5,6,7,8,9,10};
[self setDoubleDigits:bufferDoubleDigits];

What does $1 [QSA,L] mean in my .htaccess file?

This will capture requests for files like version, release, and README.md, etc. which should be treated either as endpoints, if defined (as in the case of /release), or as "not found."

How to get access to job parameters from ItemReader, in Spring Batch?

To be able to use the jobParameters I think you need to define your reader as scope 'step', but I am not sure if you can do it using annotations.

Using xml-config it would go like this:

<bean id="foo-readers" scope="step"
  class="...MyReader">
  <property name="fileName" value="#{jobExecutionContext['fileName']}" />
</bean>

See further at the Spring Batch documentation.

Perhaps it works by using @Scope and defining the step scope in your xml-config:

<bean class="org.springframework.batch.core.scope.StepScope" />

PHP mailer multiple address

You need to call the AddAddress method once for every recipient. Like so:

$mail->AddAddress('[email protected]', 'Person One');
$mail->AddAddress('[email protected]', 'Person Two');
// ..

Better yet, add them as Carbon Copy recipients.

$mail->AddCC('[email protected]', 'Person One');
$mail->AddCC('[email protected]', 'Person Two');
// ..

To make things easy, you should loop through an array to do this.

$recipients = array(
   '[email protected]' => 'Person One',
   '[email protected]' => 'Person Two',
   // ..
);
foreach($recipients as $email => $name)
{
   $mail->AddCC($email, $name);
}

How to concatenate multiple column values into a single column in Panda dataframe

If you have a list of columns you want to concatenate and maybe you'd like to use some separator, here's what you can do

def concat_columns(df, cols_to_concat, new_col_name, sep=" "):
    df[new_col_name] = df[cols_to_concat[0]]
    for col in cols_to_concat[1:]:
        df[new_col_name] = df[new_col_name].astype(str) + sep + df[col].astype(str)

This should be faster than apply and takes an arbitrary number of columns to concatenate.

$(this).val() not working to get text from span using jquery

-None of the above consistently worked for me. So here is the solution i worked out that works consistently across all browsers as it uses basic functionality. Hope this may help others. Using jQuery 8.2

1) Get the jquery object for "span". 2) Get the DOM object from above. Using jquery .get(0) 3) Using DOM's object's innerText get the text.

Here is a simple example

var curSpan = $(this).parent().children(' span').get(0);
var spansText = curSpan.innerText;

HTML

<div >
<input type='checkbox' /><span >testinput</span> 
</div>

How to make audio autoplay on chrome

Solution without using iframe, or javascript:

<embed src="silence.mp3" type="audio/mp3" autostart="true" hidden="true">
        <audio id="player" autoplay controls><source src="source/audio.mp3" type="audio/mp3"></audio>

With this solution, the open/save dialog of Internet Explorer is also avoided.

_x000D_
_x000D_
   <embed src="http://deinesv.cf/silence.mp3" type="audio/mp3" autostart="true" hidden="true">
        <audio id="player" autoplay controls><source src="https://freemusicarchive.org/file/music/ccCommunity/Mild_Wild/a_Alright_Okay_b_See_Through/Mild_Wild_-_Alright_Okay.mp3" type="audio/mp3"></audio>
_x000D_
_x000D_
_x000D_

Ruby: How to convert a string to boolean

In a rails 5.1 app, I use this core extension built on top of ActiveRecord::Type::Boolean. It is working perfectly for me when I deserialize boolean from JSON string.

https://api.rubyonrails.org/classes/ActiveModel/Type/Boolean.html

# app/lib/core_extensions/string.rb
module CoreExtensions
  module String
    def to_bool
      ActiveRecord::Type::Boolean.new.deserialize(downcase.strip)
    end
  end
end

initialize core extensions

# config/initializers/core_extensions.rb
String.include CoreExtensions::String

rspec

# spec/lib/core_extensions/string_spec.rb
describe CoreExtensions::String do
  describe "#to_bool" do
    %w[0 f F false FALSE False off OFF Off].each do |falsey_string|
      it "converts #{falsey_string} to false" do
        expect(falsey_string.to_bool).to eq(false)
      end
    end
  end
end

MySQL ORDER BY rand(), name ASC

Instead of using a subquery, you could use two separate queries, one to get the number of rows and the other to select the random rows.

SELECT COUNT(id) FROM users; #id is the primary key

Then, get a random twenty rows.

$start_row = mt_rand(0, $total_rows - 20);

The final query:

SELECT * FROM users ORDER BY name ASC LIMIT $start_row, 20;

How to get the MD5 hash of a file in C++?

A rework of impementation by @D'Nabre for C++. Don't forget to compile with -lcrypto at the end: gcc md5.c -o md5 -lcrypto.

#include <iostream>
#include <iomanip>
#include <fstream>
#include <string>

#include <openssl/md5.h>
using namespace std;

unsigned char result[MD5_DIGEST_LENGTH];

// function to print MD5 correctly
void printMD5(unsigned char* md, long size = MD5_DIGEST_LENGTH) {
    for (int i=0; i<size; i++) {
        cout<< hex << setw(2) << setfill('0') << (int) md[i];
    }
}

int main(int argc, char *argv[]) {

if(argc != 2) {
    cout << "Specify the file..." << endl;
    return 0;
}

ifstream::pos_type fileSize;
char * memBlock;

ifstream file (argv[1], ios::ate);

//check if opened
if (file.is_open() ) { cout<< "Using file\t"<< argv[1]<<endl; }
else {
    cout<< "Unnable to open\t"<< argv[1]<<endl;
    return 0;
}

//get file size & copy file to memory
//~ file.seekg(-1,ios::end); // exludes EOF
fileSize = file.tellg();
cout << "File size \t"<< fileSize << endl;
memBlock = new char[fileSize];
file.seekg(0,ios::beg);
file.read(memBlock, fileSize);
file.close();

//get md5 sum
MD5((unsigned char*) memBlock, fileSize, result);

//~ cout << "MD5_DIGEST_LENGTH = "<< MD5_DIGEST_LENGTH << endl;
printMD5(result);
cout<<endl;

return 0;
}

jQuery UI Dialog - missing close icon

I found three fixes:

  1. You can just load bootsrap first. And them load jquery-ui. But it is not good idea. Because you will see errors in console.
  2. This:

    var bootstrapButton = $.fn.button.noConflict();
    $.fn.bootstrapBtn = bootstrapButton;
    

    helps. But other buttons look terrible. And now we don't have bootstrap buttons.

  3. I just want to use bootsrap styles and also I want to have close button with an icon. I've done following:

    How close button looks after fix

    .ui-dialog-titlebar-close {
        padding:0 !important;
    }
    
    .ui-dialog-titlebar-close:after {
        content: '';
        width: 20px;
        height: 20px;
        display: inline-block;
        /* Change path to image*/
        background-image: url(themes/base/images/ui-icons_777777_256x240.png);
        background-position: -96px -128px;
        background-repeat: no-repeat;
    }
    

How to change symbol for decimal point in double.ToString()?

You can change the decimal separator by changing the culture used to display the number. Beware however that this will change everything else about the number (eg. grouping separator, grouping sizes, number of decimal places). From your question, it looks like you are defaulting to a culture that uses a comma as a decimal separator.

To change just the decimal separator without changing the culture, you can modify the NumberDecimalSeparator property of the current culture's NumberFormatInfo.

Thread.CurrentCulture.NumberFormat.NumberDecimalSeparator = ".";

This will modify the current culture of the thread. All output will now be altered, meaning that you can just use value.ToString() to output the format you want, without worrying about changing the culture each time you output a number.

(Note that a neutral culture cannot have its decimal separator changed.)

How to atomically delete keys matching a pattern using Redis

Please use this command and try :

redis-cli --raw keys "$PATTERN" | xargs redis-cli del

How to insert a new key value pair in array in php?

Try this:

foreach($array as $k => $obj) { 
    $obj->{'newKey'} = "value"; 
}

How to return more than one value from a function in Python?

You separate the values you want to return by commas:

def get_name():
   # you code
   return first_name, last_name

The commas indicate it's a tuple, so you could wrap your values by parentheses:

return (first_name, last_name)

Then when you call the function you a) save all values to one variable as a tuple, or b) separate your variable names by commas

name = get_name() # this is a tuple
first_name, last_name = get_name()
(first_name, last_name) = get_name() # You can put parentheses, but I find it ugly

How to change the background color of Action Bar's Option Menu in Android 4.2?

Within your app theme you can set the android:itemBackground property to change the color of the action menu.

For example:

_x000D_
_x000D_
<style name="AppThemeDark" parent="Theme.AppCompat.Light.DarkActionBar">_x000D_
        <item name="colorPrimary">@color/drk_colorPrimary</item>_x000D_
        <item name="colorPrimaryDark">@color/drk_colorPrimaryDark</item>_x000D_
        <item name="colorAccent">@color/drk_colorAccent</item>_x000D_
        <item name="actionBarStyle">@style/NoTitle</item>_x000D_
        <item name="windowNoTitle">true</item>_x000D_
        <item name="android:textColor">@color/white</item>_x000D_
_x000D_
        <!-- THIS IS WHERE YOU CHANGE THE COLOR -->_x000D_
        <item name="android:itemBackground">@color/drk_colorPrimary</item>_x000D_
</style>
_x000D_
_x000D_
_x000D_

How can I see if a Perl hash already has a certain key?

I guess that this code should answer your question:

use strict;
use warnings;

my @keys = qw/one two three two/;
my %hash;
for my $key (@keys)
{
    $hash{$key}++;
}

for my $key (keys %hash)
{
   print "$key: ", $hash{$key}, "\n";
}

Output:

three: 1
one: 1
two: 2

The iteration can be simplified to:

$hash{$_}++ for (@keys);

(See $_ in perlvar.) And you can even write something like this:

$hash{$_}++ or print "Found new value: $_.\n" for (@keys);

Which reports each key the first time it’s found.

ListBox with ItemTemplate (and ScrollBar!)

ListBox will try to expand in height that is available.. When you set the Height property of ListBox you get a scrollviewer that actually works...

If you wish your ListBox to accodate the height available, you might want to try to regulate the Height from your parent controls.. In a Grid for example, setting the Height to Auto in your RowDefinition might do the trick...

HTH

Chrome dev tools fails to show response even the content returned has header Content-Type:text/html; charset=UTF-8

I think this only happens when you have 'Preserve log' checked and you are trying to view the response data of a previous request after you have navigated away.

For example, I viewed the Response to loading this Stack Overflow question. You can see it.

Response Data

The second time, I reloaded this page but didn't look at the Headers or Response. I navigated to a different website. Now when I look at the response, it shows 'Failed to load response data'.

No Response Data

This is a known issue, that's been around for a while, and debated a lot. However, there is a workaround, in which you pause on onunload, so you can view the response before it navigates away, and thereby doesn't lose the data upon navigating away.

window.onunload = function() { debugger; }

Can you 'exit' a loop in PHP?

As stated in other posts, you can use the break keyword. One thing that was hinted at but not explained is that the keyword can take a numeric value to tell PHP how many levels to break from.

For example, if you have three foreach loops nested in each other trying to find a piece of information, you could do 'break 3' to get out of all three nested loops. This will work for the 'for', 'foreach', 'while', 'do-while', or 'switch' structures.

$person = "Rasmus Lerdorf";
$found = false;

foreach($organization as $oKey=>$department)
{
   foreach($department as $dKey=>$group)
   {
      foreach($group as $gKey=>$employee)
      {
         if ($employee['fullname'] == $person)
         {
            $found = true;
            break 3;
         }
      } // group
   } // department
} // organization

How to use andWhere and orWhere in Doctrine?

$q->where("a = 1")
  ->andWhere("b = 1 OR b = 2")
  ->andWhere("c = 2 OR c = 2")
  ;

How to validate a url in Python? (Malformed or not)

Not directly relevant, but often it's required to identify whether some token CAN be a url or not, not necessarily 100% correctly formed (ie, https part omitted and so on). I've read this post and did not find the solution, so I am posting my own here for the sake of completeness.

def get_domain_suffixes():
    import requests
    res=requests.get('https://publicsuffix.org/list/public_suffix_list.dat')
    lst=set()
    for line in res.text.split('\n'):
        if not line.startswith('//'):
            domains=line.split('.')
            cand=domains[-1]
            if cand:
                lst.add('.'+cand)
    return tuple(sorted(lst))

domain_suffixes=get_domain_suffixes()

def reminds_url(txt:str):
    """
    >>> reminds_url('yandex.ru.com/somepath')
    True
    
    """
    ltext=txt.lower().split('/')[0]
    return ltext.startswith(('http','www','ftp')) or ltext.endswith(domain_suffixes)

How do I compare two strings in Perl?

print "Matched!\n" if ($str1 eq $str2)

Perl has seperate string comparison and numeric comparison operators to help with the loose typing in the language. You should read perlop for all the different operators.

PHP: How to check if image file exists?

file_exists($filepath) will return a true result for a directory and full filepath, so is not always a solution when a filename is not passed.

is_file($filepath) will only return true for fully filepaths

Check if string begins with something?

First, lets extend the string object. Thanks to Ricardo Peres for the prototype, I think using the variable 'string' works better than 'needle' in the context of making it more readable.

String.prototype.beginsWith = function (string) {
    return(this.indexOf(string) === 0);
};

Then you use it like this. Caution! Makes the code extremely readable.

var pathname = window.location.pathname;
if (pathname.beginsWith('/sub/1')) {
    // Do stuff here
}

How to use a PHP class from another file?

use

require_once(__DIR__.'/_path/_of/_filename.php');

This will also help in importing files in from different folders. Try extends method to inherit the classes in that file and reuse the functions

How to do a JUnit assert on a message in a logger

Here is what i did for logback.

I created a TestAppender class:

public class TestAppender extends AppenderBase<ILoggingEvent> {

    private Stack<ILoggingEvent> events = new Stack<ILoggingEvent>();

    @Override
    protected void append(ILoggingEvent event) {
        events.add(event);
    }

    public void clear() {
        events.clear();
    }

    public ILoggingEvent getLastEvent() {
        return events.pop();
    }
}

Then in the parent of my testng unit test class I created a method:

protected TestAppender testAppender;

@BeforeClass
public void setupLogsForTesting() {
    Logger root = (Logger)LoggerFactory.getLogger(Logger.ROOT_LOGGER_NAME);
    testAppender = (TestAppender)root.getAppender("TEST");
    if (testAppender != null) {
        testAppender.clear();
    }
}

I have a logback-test.xml file defined in src/test/resources and I added a test appender:

<appender name="TEST" class="com.intuit.icn.TestAppender">
    <encoder>
        <pattern>%m%n</pattern>
    </encoder>
</appender>

and added this appender to the root appender:

<root>
    <level value="error" />
    <appender-ref ref="STDOUT" />
    <appender-ref ref="TEST" />
</root>

Now in my test classes that extend from my parent test class I can get the appender and get the last message logged and verify the message, the level, the throwable.

ILoggingEvent lastEvent = testAppender.getLastEvent();
assertEquals(lastEvent.getMessage(), "...");
assertEquals(lastEvent.getLevel(), Level.WARN);
assertEquals(lastEvent.getThrowableProxy().getMessage(), "...");

How to create an AVD for Android 4.0

I just did the same. If you look in the "Android SDK Manager" in the "Android 4.0 (API 14)" section you'll see a few packages. One of these is named "ARM EABI v7a System Image".

This is what you need to download in order to create an Android 4.0 virtual device:

The Android SDK download system

Access all Environment properties as a Map or Properties object

The other answers have pointed out the solution for the majority of cases involving PropertySources, but none have mentioned that certain property sources are unable to be casted into useful types.

One such example is the property source for command line arguments. The class that is used is SimpleCommandLinePropertySource. This private class is returned by a public method, thus making it extremely tricky to access the data inside the object. I had to use reflection in order to read the data and eventually replace the property source.

If anyone out there has a better solution, I would really like to see it; however, this is the only hack I have gotten to work.

Select rows having 2 columns equal value

SELECT *
FROM my_table
WHERE column_a <=> column_b AND column_a <=> column_c

how to implement login auth in node.js

_x000D_
_x000D_
======authorization====== MIDDLEWARE_x000D_
_x000D_
const jwt = require('../helpers/jwt')_x000D_
const User = require('../models/user')_x000D_
_x000D_
module.exports = {_x000D_
  authentication: function(req, res, next) {_x000D_
    try {_x000D_
      const user = jwt.verifyToken(req.headers.token, process.env.JWT_KEY)_x000D_
      User.findOne({ email: user.email }).then(result => {_x000D_
        if (result) {_x000D_
          req.body.user = result_x000D_
          req.params.user = result_x000D_
          next()_x000D_
        } else {_x000D_
          throw new Error('User not found')_x000D_
        }_x000D_
      })_x000D_
    } catch (error) {_x000D_
      console.log('langsung dia masuk sini')_x000D_
_x000D_
      next(error)_x000D_
    }_x000D_
  },_x000D_
_x000D_
  adminOnly: function(req, res, next) {_x000D_
    let loginUser = req.body.user_x000D_
    if (loginUser && loginUser.role === 'admin') {_x000D_
      next()_x000D_
    } else {_x000D_
      next(new Error('Not Authorized'))_x000D_
    }_x000D_
  }_x000D_
}_x000D_
_x000D_
====error handler==== MIDDLEWARE_x000D_
const errorHelper = require('../helpers/errorHandling')_x000D_
_x000D_
module.exports = function(err, req, res, next) {_x000D_
  //   console.log(err)_x000D_
  let errorToSend = errorHelper(err)_x000D_
  // console.log(errorToSend)_x000D_
  res.status(errorToSend.statusCode).json(errorToSend)_x000D_
}_x000D_
_x000D_
_x000D_
====error handling==== HELPER_x000D_
var nodeError = ["Error","EvalError","InternalError","RangeError","ReferenceError","SyntaxError","TypeError","URIError"]_x000D_
var mongooseError = ["MongooseError","DisconnectedError","DivergentArrayError","MissingSchemaError","DocumentNotFoundError","MissingSchemaError","ObjectExpectedError","ObjectParameterError","OverwriteModelError","ParallelSaveError","StrictModeError","VersionError"]_x000D_
var mongooseErrorFromClient = ["CastError","ValidatorError","ValidationError"];_x000D_
var jwtError = ["TokenExpiredError","JsonWebTokenError","NotBeforeError"]_x000D_
_x000D_
function nodeErrorMessage(message){_x000D_
    switch(message){_x000D_
        case "Token is undefined":{_x000D_
            return 403;_x000D_
        }_x000D_
        case "User not found":{_x000D_
            return 403;_x000D_
        }_x000D_
        case "Not Authorized":{_x000D_
            return 401;_x000D_
        }_x000D_
        case "Email is Invalid!":{_x000D_
            return 400;_x000D_
        }_x000D_
        case "Password is Invalid!":{_x000D_
            return 400;_x000D_
        }_x000D_
        case "Incorrect password for register as admin":{_x000D_
            return 400;_x000D_
        }_x000D_
        case "Item id not found":{_x000D_
            return 400;_x000D_
        }_x000D_
        case "Email or Password is invalid": {_x000D_
            return 400_x000D_
        }_x000D_
        default :{_x000D_
            return 500;_x000D_
        }_x000D_
    }_x000D_
}_x000D_
_x000D_
module.exports = function(errorObject){_x000D_
    // console.log("===ERROR OBJECT===")_x000D_
    // console.log(errorObject)_x000D_
    // console.log("===ERROR STACK===")_x000D_
    // console.log(errorObject.stack);_x000D_
_x000D_
    let statusCode = 500;  _x000D_
    let returnObj = {_x000D_
        error : errorObject_x000D_
    }_x000D_
    if(jwtError.includes(errorObject.name)){_x000D_
        statusCode = 403;_x000D_
        returnObj.message = "Token is Invalid"_x000D_
        returnObj.source = "jwt"_x000D_
    }_x000D_
    else if(nodeError.includes(errorObject.name)){_x000D_
        returnObj.error = JSON.parse(JSON.stringify(errorObject, ["message", "arguments", "type", "name"]))_x000D_
        returnObj.source = "node";_x000D_
        statusCode = nodeErrorMessage(errorObject.message);_x000D_
        returnObj.message = errorObject.message;_x000D_
    }else if(mongooseError.includes(errorObject.name)){_x000D_
        returnObj.source = "database"_x000D_
        returnObj.message = "Error from server"_x000D_
    }else if(mongooseErrorFromClient.includes(errorObject.name)){_x000D_
        returnObj.source = "database";_x000D_
        errorObject.message ? returnObj.message = errorObject.message : returnObj.message = "Bad Request"_x000D_
        statusCode = 400;_x000D_
    }else{_x000D_
        returnObj.source = "unknown error";_x000D_
        returnObj.message = "Something error";_x000D_
    }_x000D_
    returnObj.statusCode = statusCode;_x000D_
    _x000D_
    return returnObj;_x000D_
_x000D_
_x000D_
}_x000D_
_x000D_
_x000D_
===jwt====_x000D_
const jwt = require('jsonwebtoken')_x000D_
_x000D_
function generateToken(payload) {_x000D_
    let token = jwt.sign(payload, process.env.JWT_KEY)_x000D_
    return token_x000D_
}_x000D_
_x000D_
function verifyToken(token) {_x000D_
    let payload = jwt.verify(token, process.env.JWT_KEY)_x000D_
    return payload_x000D_
}_x000D_
_x000D_
module.exports = {_x000D_
    generateToken, verifyToken_x000D_
}_x000D_
_x000D_
===router index===_x000D_
const express = require('express')_x000D_
const router = express.Router()_x000D_
_x000D_
// router.get('/', )_x000D_
router.use('/users', require('./users'))_x000D_
router.use('/products', require('./product'))_x000D_
router.use('/transactions', require('./transaction'))_x000D_
_x000D_
module.exports = router_x000D_
_x000D_
====router user ====_x000D_
const express = require('express')_x000D_
const router = express.Router()_x000D_
const User = require('../controllers/userController')_x000D_
const auth = require('../middlewares/auth')_x000D_
_x000D_
/* GET users listing. */_x000D_
router.post('/register', User.register)_x000D_
router.post('/login', User.login)_x000D_
router.get('/', auth.authentication, User.getUser)_x000D_
router.post('/logout', auth.authentication, User.logout)_x000D_
module.exports = router_x000D_
_x000D_
_x000D_
====app====_x000D_
require('dotenv').config()_x000D_
const express = require('express')_x000D_
const cookieParser = require('cookie-parser')_x000D_
const logger = require('morgan')_x000D_
const cors = require('cors')_x000D_
const indexRouter = require('./routes/index')_x000D_
const errorHandler = require('./middlewares/errorHandler')_x000D_
const mongoose = require('mongoose')_x000D_
const app = express()_x000D_
_x000D_
mongoose.connect(process.env.DB_URI, {_x000D_
  useNewUrlParser: true,_x000D_
  useUnifiedTopology: true,_x000D_
  useCreateIndex: true,_x000D_
  useFindAndModify: false_x000D_
})_x000D_
_x000D_
app.use(cors())_x000D_
app.use(logger('dev'))_x000D_
app.use(express.json())_x000D_
app.use(express.urlencoded({ extended: false }))_x000D_
app.use(cookieParser())_x000D_
_x000D_
app.use('/', indexRouter)_x000D_
app.use(errorHandler)_x000D_
_x000D_
module.exports = app
_x000D_
_x000D_
_x000D_

Swift: Testing optionals for nil

var xyz : NSDictionary?

// case 1:
xyz = ["1":"one"]
// case 2: (empty dictionary)
xyz = NSDictionary() 
// case 3: do nothing

if xyz { NSLog("xyz is not nil.") }
else   { NSLog("xyz is nil.")     }

This test worked as expected in all cases. BTW, you do not need the brackets ().

How to loop backwards in python?

To reverse a string without using reversed or [::-1], try something like:

def reverse(text):
    # Container for reversed string
    txet=""

    # store the length of the string to be reversed
    # account for indexes starting at 0
    length = len(text)-1

    # loop through the string in reverse and append each character
    # deprecate the length index
    while length>=0:
        txet += "%s"%text[length]
        length-=1
    return txet

Random number generator only generating one random number

I would rather use the following class to generate random numbers:

byte[] random;
System.Security.Cryptography.RNGCryptoServiceProvider prov = new System.Security.Cryptography.RNGCryptoServiceProvider();
prov.GetBytes(random);

Reading a resource file from within jar

Below code works with Spring boot(kotlin):

val authReader = InputStreamReader(javaClass.getResourceAsStream("/file1.json"))

Is it a good practice to place C++ definitions in header files?

What might be informing you coworker is a notion that most C++ code should be templated to allow for maximum usability. And if it's templated, then everything will need to be in a header file, so that client code can see it and instantiate it. If it's good enough for Boost and the STL, it's good enough for us.

I don't agree with this point of view, but it may be where it's coming from.

How can I show the table structure in SQL Server query?

On SQL Server 2012, you can use the following stored procedure:

sp_columns '<table name>'

For example, given a database table named users:

sp_columns 'users'

Direct casting vs 'as' operator?

If you already know what type it can cast to, use a C-style cast:

var o = (string) iKnowThisIsAString; 

Note that only with a C-style cast can you perform explicit type coercion.

If you don't know whether it's the desired type and you're going to use it if it is, use as keyword:

var s = o as string;
if (s != null) return s.Replace("_","-");

//or for early return:
if (s==null) return;

Note that as will not call any type conversion operators. It will only be non-null if the object is not null and natively of the specified type.

Use ToString() to get a human-readable string representation of any object, even if it can't cast to string.

Move an item inside a list?

A slightly shorter solution, that only moves the item to the end, not anywhere is this:

l += [l.pop(0)]

For example:

>>> l = [1,2,3,4,5]
>>> l += [l.pop(0)]
>>> l
[2, 3, 4, 5, 1]

How to format date in angularjs

Ok the issue it seems to come from this line:
https://github.com/angular-ui/ui-date/blob/master/src/date.js#L106.

Actually this line it's the binding with jQuery UI which it should be the place to inject the data format.

As you can see in var opts there is no property dateFormat with the value from ng-date-format as you could espect.

Anyway the directive has a constant called uiDateConfig to add properties to opts.

The flexible solution (recommended):

From here you can see you can insert some options injecting in the directive a controller variable with the jquery ui options.

<input ui-date="dateOptions" ui-date-format="mm/dd/yyyy" ng-model="valueofdate" />

myAppModule.controller('MyController', function($scope) {
    $scope.dateOptions = {
        dateFormat: "dd-M-yy"
    };
});

The hardcoded solution:

If you don't want to repeat this procedure all the time change the value of uiDateConfig in date.js to:

.constant('uiDateConfig', { dateFormat: "dd-M-yy" })

What is the difference between an Instance and an Object?

Object refers to class and instance refers to an object.In other words instance is a copy of an object with particular values in it.

Java 'file.delete()' Is not Deleting Specified File

If you want to delete file first close all the connections and streams. after that delete the file.

Google maps API V3 - multiple markers on exact same spot

Check this: https://github.com/plank/MarkerClusterer

This is the MarkerCluster modified to have a infoWindow in a cluster marker, when you have several markers in the same position.

You can see how it works here: http://culturedays.ca/en/2013-activities

Enum Naming Convention - Plural

On the other thread C# naming convention for enum and matching property someone pointed out what I think is a very good idea:

"I know my suggestion goes against the .NET Naming conventions, but I personally prefix enums with 'E' and enum flags with 'F' (similar to how we prefix Interfaces with 'I')."

How to get cookie expiration date / creation date from javascript?

One possibility is to delete to cookie you are looking for the expiration date from and rewrite it. Then you'll know the expiration date.

Make the current commit the only (initial) commit in a Git repository?

The other option, which could turn out to be a lot of work if you have a lot of commits, is an interactive rebase (assuming your git version is >=1.7.12):git rebase --root -i

When presented with a list of commits in your editor:

  • Change "pick" to "reword" for the first commit
  • Change "pick" to "fixup" every other commit

Save and close. Git will start rebasing.

At the end you would have a new root commit that is a combination of all the ones that came after it.

The advantage is that you don't have to delete your repository and if you have second thoughts you always have a fallback.

If you really do want to nuke your history, reset master to this commit and delete all other branches.

Remove non-ascii character in string

It can also be done with a positive assertion of removal, like this:

textContent = textContent.replace(/[\u{0080}-\u{FFFF}]/gu,"");

This uses unicode. In Javascript, when expressing unicode for a regular expression, the characters are specified with the escape sequence \u{xxxx} but also the flag 'u' must present; note the regex has flags 'gu'.

I called this a "positive assertion of removal" in the sense that a "positive" assertion expresses which characters to remove, while a "negative" assertion expresses which letters to not remove. In many contexts, the negative assertion, as stated in the prior answers, might be more suggestive to the reader. The circumflex "^" says "not" and the range \x00-\x7F says "ascii," so the two together say "not ascii."

textContent = textContent.replace(/[^\x00-\x7F]/g,"");

That's a great solution for English language speakers who only care about the English language, and its also a fine answer for the original question. But in a more general context, one cannot always accept the cultural bias of assuming "all non-ascii is bad." For contexts where non-ascii is used, but occasionally needs to be stripped out, the positive assertion of Unicode is a better fit.

A good indication that zero-width, non printing characters are embedded in a string is when the string's "length" property is positive (nonzero), but looks like (i.e. prints as) an empty string. For example, I had this showing up in the Chrome debugger, for a variable named "textContent":

> textContent
""
> textContent.length
7

This prompted me to want to see what was in that string.

> encodeURI(textContent)
"%E2%80%8B%E2%80%8B%E2%80%8B%E2%80%8B%E2%80%8B%E2%80%8B%E2%80%8B"

This sequence of bytes seems to be in the family of some Unicode characters that get inserted by word processors into documents, and then find their way into data fields. Most commonly, these symbols occur at the end of a document. The zero-width-space "%E2%80%8B" might be inserted by CK-Editor (CKEditor).

encodeURI()  UTF-8     Unicode  html     Meaning
-----------  --------  -------  -------  -------------------
"%E2%80%8B"  EC 80 8B  U 200B   &#8203;  zero-width-space
"%E2%80%8E"  EC 80 8E  U 200E   &#8206;  left-to-right-mark
"%E2%80%8F"  EC 80 8F  U 200F   &#8207;  right-to-left-mark

Some references on those:

http://www.fileformat.info/info/unicode/char/200B/index.htm

https://en.wikipedia.org/wiki/Left-to-right_mark

Note that although the encoding of the embedded character is UTF-8, the encoding in the regular expression is not. Although the character is embedded in the string as three bytes (in my case) of UTF-8, the instructions in the regular expression must use the two-byte Unicode. In fact, UTF-8 can be up to four bytes long; it is less compact than Unicode because it uses the high bit (or bits) to escape the standard ascii encoding. That's explained here:

https://en.wikipedia.org/wiki/UTF-8

JBoss AS 7: How to clean up tmp?

As you know JBoss is a purely filesystem based installation. To install you simply unzip a file and thats it. Once you install a certain folder structure is created by default and as you run the JBoss instance for the first time, it creates additional folders for runtime operation. For comparison here is the structure of JBoss AS 7 before and after you start for the first time

Before

jboss-as-7
 |
 |---> standalone
 |      |----> lib
 |      |----> configuration
 |      |----> deployments
 |      
 |---> domain
 |....

After

jboss-as-7
     |
     |---> standalone
     |      |----> lib
     |      |----> configuration
     |      |----> deployments
     |      |----> tmp
     |      |----> data
     |      |----> log
     |      
     |---> domain
     |....

As you can see 3 new folders are created (log, data & tmp). These folders can all be deleted without effecting the application deployed in deployments folder unless your application generated Data that's stored in those folders. In development, its ok to delete all these 3 new folders assuming you don't have any need for the logs and data stored in "data" directory.

For production, ITS NOT RECOMMENDED to delete these folders as there maybe application generated data that stores certain state of the application. For ex, in the data folder, the appserver can save critical Tx rollback logs. So contact your JBoss Administrator if you need to delete those folders for any reason in production.

Good luck!

Fragment transaction animation: slide in and slide out

This is another solution which I use:

public class CustomAnimator {
    private static final String TAG = "com.example.CustomAnimator";

    private static Stack<AnimationEntry> animation_stack    = new Stack<>();

    public static final int                 DIRECTION_LEFT  = 1;
    public static final int                 DIRECTION_RIGHT = -1;
    public static final int                 DIRECTION_UP    = 2;
    public static final int                 DIRECTION_DOWN  = -2;

    static class AnimationEntry {
        View in;
        View    out;
        int     direction;
        long    duration;
    }

    public static boolean hasHistory() {
        return !animation_stack.empty();
    }

    public static void reversePrevious() {
        if (!animation_stack.empty()) {
            AnimationEntry entry = animation_stack.pop();
            slide(entry.out, entry.in, -entry.direction, entry.duration, false);
        }
    }

    public static void clearHistory() {
        animation_stack.clear();
    }

    public static void slide(final View in, View out, final int direction, long duration) {
        slide(in, out, direction, duration, true);
    }

    private static void slide(final View in, final View out, final int direction, final long duration, final boolean save) {

        ViewGroup in_parent = (ViewGroup) in.getParent();
        ViewGroup out_parent = (ViewGroup) out.getParent();

        if (!in_parent.equals(out_parent)) {
            return;
        }

        int parent_width = in_parent.getWidth();
        int parent_height = in_parent.getHeight();

        ObjectAnimator slide_out;
        ObjectAnimator slide_in;

        switch (direction) {
            case DIRECTION_LEFT:
            default:
                slide_in = ObjectAnimator.ofFloat(in, "translationX", parent_width, 0);
                slide_out = ObjectAnimator.ofFloat(out, "translationX", 0, -out.getWidth());
                break;
            case DIRECTION_RIGHT:
                slide_in = ObjectAnimator.ofFloat(in, "translationX", -out.getWidth(), 0);
                slide_out = ObjectAnimator.ofFloat(out, "translationX", 0, parent_width);
                break;
            case DIRECTION_UP:
                slide_in = ObjectAnimator.ofFloat(in, "translationY", parent_height, 0);
                slide_out = ObjectAnimator.ofFloat(out, "translationY", 0, -out.getHeight());
                break;
            case DIRECTION_DOWN:
                slide_in = ObjectAnimator.ofFloat(in, "translationY", -out.getHeight(), 0);
                slide_out = ObjectAnimator.ofFloat(out, "translationY", 0, parent_height);
                break;
        }

        AnimatorSet animations = new AnimatorSet();
        animations.setDuration(duration);
        animations.playTogether(slide_in, slide_out);
        animations.addListener(new Animator.AnimatorListener() {

            @Override
            public void onAnimationCancel(Animator arg0) {
            }

            @Override
            public void onAnimationEnd(Animator arg0) {
                out.setVisibility(View.INVISIBLE);
                if (save) {
                    AnimationEntry ae = new AnimationEntry();
                    ae.in = in;
                    ae.out = out;
                    ae.direction = direction;
                    ae.duration = duration;
                    animation_stack.push(ae);
                }
            }

            @Override
            public void onAnimationRepeat(Animator arg0) {
            }

            @Override
            public void onAnimationStart(Animator arg0) {
                in.setVisibility(View.VISIBLE);
            }
        });
        animations.start();
    }
}

The usage of class. Let's say you have two fragments (list and details fragments)as shown below

<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/ui_container"
    android:layout_width="match_parent"
    android:layout_height="match_parent" >

    <FrameLayout
        android:id="@+id/list_container"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />

    <FrameLayout
        android:id="@+id/details_container"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:visibility="gone" />
</FrameLayout>

Usage

View details_container = findViewById(R.id.details_container);
View list_container = findViewById(R.id.list_container);
// You can select the direction left/right/up/down and the duration
CustomAnimator.slide(list_container, details_container,CustomAnimator.DIRECTION_LEFT, 400);

You can use the function CustomAnimator.reversePrevious();to get the previous view when the user pressed back.

Powershell script does not run via Scheduled Tasks

One more idea that worked. It's really silly, but, apparently, the default target OS setting (bottom right corner of the screen) is Vista / Windows Server 2008. As we're past the 10 year mark, it is likely that your Powershell script will not be compatible to these.

Changing the target to Windows Server 2016, as shown on the screenshot below, did the trick for me.

Change the setting on the screenshot

Select entries between dates in doctrine 2

Look how I format my date $jour in the parameters. It depends if you use a expr()->like or a expr()->lte

$qb
        ->select('e')
        ->from('LdbPlanningBundle:EventEntity', 'e')
        ->where(
            $qb->expr()->andX(
                $qb->expr()->orX(
                    $qb->expr()->like('e.start', ':jour1'),
                    $qb->expr()->like('e.end', ':jour1'),
                    $qb->expr()->andX(
                        $qb->expr()->lte('e.start', ':jour2'),
                        $qb->expr()->gte('e.end', ':jour2')
                    )
                ),
                $qb->expr()->eq('e.user', ':user')
            )
        )
        ->andWhere('e.user = :user ')
        ->setParameter('user', $user)
        ->setParameter('jour1', '%'.$jour->format('Y-m-d').'%')
        ->setParameter('jour2', $jour->format('Y-m-d'))
        ->getQuery()
        ->getArrayResult()
    ;

Capture keyboardinterrupt in Python without try-except

Yes, you can install an interrupt handler using the module signal, and wait forever using a threading.Event:

import signal
import sys
import time
import threading

def signal_handler(signal, frame):
    print('You pressed Ctrl+C!')
    sys.exit(0)

signal.signal(signal.SIGINT, signal_handler)
print('Press Ctrl+C')
forever = threading.Event()
forever.wait()

How do I find the install time and date of Windows?

In RunCommand write "MSINFO32" and hit enter It will show All information related to system

TypeError("'bool' object is not iterable",) when trying to return a Boolean

Look at the traceback:

Traceback (most recent call last):
  File "C:\Python33\lib\site-packages\bottle.py", line 821, in _cast
    out = iter(out)
TypeError: 'bool' object is not iterable

Your code isn't iterating the value, but the code receiving it is.

The solution is: return an iterable. I suggest that you either convert the bool to a string (str(False)) or enclose it in a tuple ((False,)).

Always read the traceback: it's correct, and it's helpful.

python NameError: global name '__file__' is not defined

Are you using the interactive interpreter? You can use

sys.argv[0]

You should read: How do I get the path of the current executed file in Python?

Why use Optional.of over Optional.ofNullable?

Your question is based on assumption that the code which may throw NullPointerException is worse than the code which may not. This assumption is wrong. If you expect that your foobar is never null due to the program logic, it's much better to use Optional.of(foobar) as you will see a NullPointerException which will indicate that your program has a bug. If you use Optional.ofNullable(foobar) and the foobar happens to be null due to the bug, then your program will silently continue working incorrectly, which may be a bigger disaster. This way an error may occur much later and it would be much harder to understand at which point it went wrong.

@UniqueConstraint and @Column(unique = true) in hibernate annotation

In addition to @Boaz's and @vegemite4me's answers....

By implementing ImplicitNamingStrategy you may create rules for automatically naming the constraints. Note you add your naming strategy to the metadataBuilder during Hibernate's initialization:

metadataBuilder.applyImplicitNamingStrategy(new MyImplicitNamingStrategy());

It works for @UniqueConstraint, but not for @Column(unique = true), which always generates a random name (e.g. UK_3u5h7y36qqa13y3mauc5xxayq).

There is a bug report to solve this issue, so if you can, please vote there to have this implemented. Here: https://hibernate.atlassian.net/browse/HHH-11586

Thanks.

How do I find ' % ' with the LIKE operator in SQL Server?

You can use ESCAPE:

WHERE columnName LIKE '%\%%' ESCAPE '\'

The proxy server received an invalid response from an upstream server

This is not mentioned in you post but I suspect you are initiating an SSL connection from the browser to Apache, where VirtualHosts are configured, and Apache does a revese proxy to your Tomcat.

There is a serious bug in (some versions ?) of IE that sends the 'wrong' host information in an SSL connection (see EDIT below) and confuses the Apache VirtualHosts. In short the server name presented is the one of the reverse DNS resolution of the IP, not the one in the URL.

The workaround is to have one IP address per SSL virtual hosts/server name. Is short, you must end up with something like

1 server name == 1 IP address == 1 certificate == 1 Apache Virtual Host

EDIT

Though the conclusion is correct, the identification of the problem is better described here http://en.wikipedia.org/wiki/Server_Name_Indication

Android getActivity() is undefined

You want getActivity() inside your class. It's better to use

yourclassname.this.getActivity()

Try this. It's helpful for you.

How to get autocomplete in jupyter notebook without using tab?

The auto-completion with Jupyter Notebook is so weak, even with hinterland extension. Thanks for the idea of deep-learning-based code auto-completion. I developed a Jupyter Notebook Extension based on TabNine which provides code auto-completion based on Deep Learning. Here's the Github link of my work: jupyter-tabnine.

It's available on pypi index now. Simply issue following commands, then enjoy it:)

pip3 install jupyter-tabnine
jupyter nbextension install --py jupyter_tabnine
jupyter nbextension enable --py jupyter_tabnine
jupyter serverextension enable --py jupyter_tabnine

demo

Using a BOOL property

There's no benefit to using properties with primitive types. @property is used with heap allocated NSObjects like NSString*, NSNumber*, UIButton*, and etc, because memory managed accessors are created for free. When you create a BOOL, the value is always allocated on the stack and does not require any special accessors to prevent memory leakage. isWorking is simply the popular way of expressing the state of a boolean value.

In another OO language you would make a variable private bool working; and two accessors: SetWorking for the setter and IsWorking for the accessor.

Difference between JE/JNE and JZ/JNZ

JE and JZ are just different names for exactly the same thing: a conditional jump when ZF (the "zero" flag) is equal to 1.

(Similarly, JNE and JNZ are just different names for a conditional jump when ZF is equal to 0.)

You could use them interchangeably, but you should use them depending on what you are doing:

  • JZ/JNZ are more appropriate when you are explicitly testing for something being equal to zero:

    dec  ecx
    jz   counter_is_now_zero
    
  • JE and JNE are more appropriate after a CMP instruction:

    cmp  edx, 42
    je   the_answer_is_42
    

    (A CMP instruction performs a subtraction, and throws the value of the result away, while keeping the flags; which is why you get ZF=1 when the operands are equal and ZF=0 when they're not.)

Java, How do I get current index/key in "for each" loop

You can't, you either need to keep the index separately:

int index = 0;
for(Element song : question) {
    System.out.println("Current index is: " + (index++));
}

or use a normal for loop:

for(int i = 0; i < question.length; i++) {
    System.out.println("Current index is: " + i);
}

The reason is you can use the condensed for syntax to loop over any Iterable, and it's not guaranteed that the values actually have an "index"

How do you format an unsigned long long int using printf?

For long long (or __int64) using MSVS, you should use %I64d:

__int64 a;
time_t b;
...
fprintf(outFile,"%I64d,%I64d\n",a,b);    //I is capital i

MySQL limit from descending order

This way is comparatively more easy

SELECT doc_id,serial_number,status FROM date_time ORDER BY  date_time DESC LIMIT 0,1;

Exposing a port on a live Docker container

There is a handy HAProxy wrapper.

docker run -it -p LOCALPORT:PROXYPORT --rm --link TARGET_CONTAINER:EZNAME -e "BACKEND_HOST=EZNAME" -e "BACKEND_PORT=PROXYPORT" demandbase/docker-tcp-proxy

This creates an HAProxy to the target container. easy peasy.

How do HashTables deal with collisions?

There are multiple techniques available to handle collision. I will explain some of them

Chaining: In chaining we use array indexes to store the values. If hash code of second value also points to the same index then we replace that index value with an linked list and all values pointing to that index are stored in the linked list and actual array index points to the head of the the linked list. But if there is only one hash code pointing to an index of array then the value is directly stored in that index. Same logic is applied while retrieving the values. This is used in Java HashMap/Hashtable to avoid collisions.

Linear probing: This technique is used when we have more index in the table than the values to be stored. Linear probing technique works on the concept of keep incrementing until you find an empty slot. The pseudo code looks like this:

index = h(k) 

while( val(index) is occupied) 

index = (index+1) mod n

Double hashing technique: In this technique we use two hashing functions h1(k) and h2(k). If the slot at h1(k) is occupied then the second hashing function h2(k) used to increment the index. The pseudo-code looks like this:

index = h1(k)

while( val(index) is occupied)

index = (index + h2(k)) mod n

Linear probing and double hashing techniques are part of open addressing technique and it can only be used if available slots are more than the number of items to be added. It takes less memory than chaining because there is no extra structure used here but its slow because of lot of movement happen until we find an empty slot. Also in open addressing technique when an item is removed from a slot we put an tombstone to indicate that the item is removed from here that is why its empty.

For more information see this site.

Find the PID of a process that uses a port on Windows

Command:

netstat -aon | findstr 4723

Output:

TCP    0.0.0.0:4723           0.0.0.0:0                LISTENING       10396

Now cut the process ID, "10396", using the for command in Windows.

Command:

for /f "tokens=5" %a in ('netstat -aon ^| findstr 4723') do @echo %~nxa

Output:

10396

If you want to cut the 4th number of the value means "LISTENING" then command in Windows.

Command:

for /f "tokens=4" %a in ('netstat -aon ^| findstr 4723') do @echo %~nxa

Output:

LISTENING

How to empty a redis database?

With redis-cli:

FLUSHDB       - Removes data from your connection's CURRENT database.
FLUSHALL      - Removes data from ALL databases.

Redis Docs: FLUSHDB, FLUSHALL

OCI runtime exec failed: exec failed: (...) executable file not found in $PATH": unknown

This happened to me on windows. Any of these commands will work

On Windows CMD (not switching to bash)

docker exec -it <container-id> /bin/sh

On Windows CMD (after switching to bash)

docker exec -it <container-id> //bin//sh

or

winpty docker exec -it <container-id> //bin//sh

On Git Bash

winpty docker exec -it <container-id> //bin//sh

NB: You might need to run use /bin/bash or /bin/sh, depending on the shell in your container.

The reason is documented in the ReleaseNotes file of Git and it is well explained here - Bash in Git for Windows: Weirdness...

"The cause has to do with trying to ensure that posix paths end up being passed to the git utilities properly. For this reason, Git for Windows includes a modified MSYS layer that affects command arguments."

Updating address bar with new URL without hash or reloading the page

Update to Davids answer to even detect browsers that do not support pushstate:

if (history.pushState) {
  window.history.pushState("object or string", "Title", "/new-url");
} else {
  document.location.href = "/new-url";
}

How to convert a structure to a byte array in C#?

This can be done very straightforwardly.

Define your struct explicitly with [StructLayout(LayoutKind.Explicit)]

int size = list.GetLength(0);
IntPtr addr = Marshal.AllocHGlobal(size * sizeof(DataStruct));
DataStruct *ptrBuffer = (DataStruct*)addr;
foreach (DataStruct ds in list)
{
    *ptrBuffer = ds;
    ptrBuffer += 1;
}

This code can only be written in an unsafe context. You have to free addr when you're done with it.

Marshal.FreeHGlobal(addr);

"Cannot evaluate expression because the code of the current method is optimized" in Visual Studio 2010

I realize this is a later answer, but I found another reference to a way to address this issue that might help others in the future. This web page describes setting an environment variable (COMPLUS_ZapDisable=1) that prevents optimization, at least it did for me! (Don't forget the second part of disabling the Visual Studio hosting process.) In my case, this might have been even more relevant because I was debugging an external DLL thru a symbol server, but I'm not sure.

Placing/Overlapping(z-index) a view above another view in android

You can't use a LinearLayout for this, but you can use a FrameLayout. In a FrameLayout, the z-index is defined by the order in which the items are added, for example:

<FrameLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    >
    <ImageView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:src="@drawable/my_drawable"
        android:scaleType="fitCenter"
        />
    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="bottom|center"
        android:padding="5dp"
        android:text="My Label"
        />
</FrameLayout>

In this instance, the TextView would be drawn on top of the ImageView, along the bottom center of the image.

SQL query to group by day

actually this depends on what DBMS you are using but in regular SQL convert(varchar,DateColumn,101) will change the DATETIME format to date (one day)

so:

SELECT 
    sum(amount) 
FROM 
    sales 
GROUP BY 
    convert(varchar,created,101)

the magix number 101 is what date format it is converted to

Is there a download function in jsFiddle?

Use http://jsfiddle.net//show/light/

then just use inspect element function of browser. you will get code in iframe tab. . in chrome just right click and cick on edit as html tab. and copy the html content. that is your actual code.