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Global Angular CLI version greater than local version

This is how I fixed it. in Visual Studio Code's terminal, First cache clean

npm cache clean --force

Then updated cli

ng update @angular/cli

If any module missing after this, use below command

npm install

'router-outlet' is not a known element

It works for me, when i add following code in app.module.ts

@NgModule({
...,
   imports: [
     AppRoutingModule
    ],
...
})

'Conda' is not recognized as internal or external command

I have Windows 10 64 bit, this worked for me, This solution can work for both (Anaconda/MiniConda) distributions.

  1. First of all try to uninstall anaconda/miniconda which is causing problem.
  2. After that delete '.anaconda' and '.conda' folders from 'C:\Users\'
  3. If you have any antivirus software installed then try to exclude all the folders,subfolders inside 'C:\ProgramData\Anaconda3\' from

    • Behaviour detection.
    • Virus detection.
    • DNA scan.
    • Suspicious files scan.
    • Any other virus protection mode.

    *(Note: 'C:\ProgramData\Anaconda3' this folder is default installation folder, you can change it just replace your excluded path at installation destination prompt while installing Anaconda)*

  4. Now install Anaconda with admin privileges.
    • Set the installation path as 'C:\ProgramData\Anaconda3' or you can specify your custom path just remember it should not contain any white space and it should be excluded from virus detection.
    • At Advanced Installation Options you can check "Add Anaconda to my PATH environment variable(optional)" and "Register Anaconda as my default Python 3.6"
    • Install it with further default settings. Click on finish after done.
    • Restart your computer.

Now open Command prompt or Anaconda prompt and check installation using following command

conda list

If you get any package list then the anaconda/miniconda is successfully installed.

HTTP Basic: Access denied fatal: Authentication failed

The updating of the password in the windows credential manager was not the solution for me.

I had to set a different remote url, by:

git remote set-url origin https://gitlab....git

The url in this case was the one that could be found in Gitlab under Clone -> Clone with HTTPS. It was not the one in the command line instructions.

Pandas create empty DataFrame with only column names

You can create an empty DataFrame with either column names or an Index:

In [4]: import pandas as pd
In [5]: df = pd.DataFrame(columns=['A','B','C','D','E','F','G'])
In [6]: df
Out[6]:
Empty DataFrame
Columns: [A, B, C, D, E, F, G]
Index: []

Or

In [7]: df = pd.DataFrame(index=range(1,10))
In [8]: df
Out[8]:
Empty DataFrame
Columns: []
Index: [1, 2, 3, 4, 5, 6, 7, 8, 9]

Edit: Even after your amendment with the .to_html, I can't reproduce. This:

df = pd.DataFrame(columns=['A','B','C','D','E','F','G'])
df.to_html('test.html')

Produces:

<table border="1" class="dataframe">
  <thead>
    <tr style="text-align: right;">
      <th></th>
      <th>A</th>
      <th>B</th>
      <th>C</th>
      <th>D</th>
      <th>E</th>
      <th>F</th>
      <th>G</th>
    </tr>
  </thead>
  <tbody>
  </tbody>
</table>

Getter and Setter of Model object in Angular 4

The way you declare the date property as an input looks incorrect but its hard to say if it's the only problem without seeing all your code. Rather than using @Input('date') declare the date property like so: private _date: string;. Also, make sure you are instantiating the model with the new keyword. Lastly, access the property using regular dot notation.

Check your work against this example from https://www.typescriptlang.org/docs/handbook/classes.html :

let passcode = "secret passcode";

class Employee {
    private _fullName: string;

    get fullName(): string {
        return this._fullName;
    }

    set fullName(newName: string) {
        if (passcode && passcode == "secret passcode") {
            this._fullName = newName;
        }
        else {
            console.log("Error: Unauthorized update of employee!");
        }
    }
}

let employee = new Employee();
employee.fullName = "Bob Smith";
if (employee.fullName) {
    console.log(employee.fullName);
}

And here is a plunker demonstrating what it sounds like you're trying to do: https://plnkr.co/edit/OUoD5J1lfO6bIeME9N0F?p=preview

ReactJS lifecycle method inside a function Component

Solution One: You can use new react HOOKS API. Currently in React v16.8.0

Hooks let you use more of React’s features without classes. Hooks provide a more direct API to the React concepts you already know: props, state, context, refs, and lifecycle. Hooks solves all the problems addressed with Recompose.

A Note from the Author of recompose (acdlite, Oct 25 2018):

Hi! I created Recompose about three years ago. About a year after that, I joined the React team. Today, we announced a proposal for Hooks. Hooks solves all the problems I attempted to address with Recompose three years ago, and more on top of that. I will be discontinuing active maintenance of this package (excluding perhaps bugfixes or patches for compatibility with future React releases), and recommending that people use Hooks instead. Your existing code with Recompose will still work, just don't expect any new features.

Solution Two:

If you are using react version that does not support hooks, no worries, use recompose(A React utility belt for function components and higher-order components.) instead. You can use recompose for attaching lifecycle hooks, state, handlers etc to a function component.

Here’s a render-less component that attaches lifecycle methods via the lifecycle HOC (from recompose).

// taken from https://gist.github.com/tsnieman/056af4bb9e87748c514d#file-auth-js-L33

function RenderlessComponent() {
  return null; 
}

export default lifecycle({

  componentDidMount() {
    const { checkIfAuthed } = this.props;
    // Do they have an active session? ("Remember me")
    checkIfAuthed();
  },

  componentWillReceiveProps(nextProps) {
    const {
      loadUser,
    } = this.props;

    // Various 'indicators'..
    const becameAuthed = (!(this.props.auth) && nextProps.auth);
    const isCurrentUser = (this.props.currentUser !== null);

    if (becameAuthed) {
      loadUser(nextProps.auth.uid);
    }

    const shouldSetCurrentUser = (!isCurrentUser && nextProps.auth);
    if (shouldSetCurrentUser) {
      const currentUser = nextProps.users[nextProps.auth.uid];
      if (currentUser) {
        this.props.setCurrentUser({
          'id': nextProps.auth.uid,
          ...currentUser,
        });
      }
    }
  }
})(RenderlessComponent);

how to find my angular version in my project?

  1. Browser > Inspect > Element >

    <.app-root _nghost-hey-c0="" ng-version="8.2.11">

  2. In terminal

    :> ng version
    :> ng --version
    :> ng -v

Angular ForEach in Angular4/Typescript?

In Typescript use the For Each like below.

selectChildren(data, $event) {
let parentChecked = data.checked;
for(var obj in this.hierarchicalData)
    {
        for (var childObj in obj )
        {
            value.checked = parentChecked;
        }
    }
}

Setting up Gradle for api 26 (Android)

Have you added the google maven endpoint?

Important: The support libraries are now available through Google's Maven repository. You do not need to download the support repository from the SDK Manager. For more information, see Support Library Setup.

Add the endpoint to your build.gradle file:

allprojects {
    repositories {
        jcenter()
        maven {
            url 'https://maven.google.com'
        }
    }
}

Which can be replaced by the shortcut google() since Android Gradle v3:

allprojects {
    repositories {
        jcenter()
        google()
    }
}

If you already have any maven url inside repositories, you can add the reference after them, i.e.:

allprojects {
    repositories {
        jcenter()
        maven {
            url 'https://jitpack.io'
        }
        maven {
            url 'https://maven.google.com'
        }
    }
}

What's the difference between implementation and compile in Gradle?

+--------------------+----------------------+-------------+--------------+-----------------------------------------+
| Name               | Role                 | Consumable? | Resolveable? | Description                             |
+--------------------+----------------------+-------------+--------------+-----------------------------------------+
| api                | Declaring            |      no     |      no      | This is where you should declare        |
|                    | API                  |             |              | dependencies which are transitively     |
|                    | dependencies         |             |              | exported to consumers, for compile.     |
+--------------------+----------------------+-------------+--------------+-----------------------------------------+
| implementation     | Declaring            |      no     |      no      | This is where you should                |
|                    | implementation       |             |              | declare dependencies which are          |
|                    | dependencies         |             |              | purely internal and not                 |
|                    |                      |             |              | meant to be exposed to consumers.       |
+--------------------+----------------------+-------------+--------------+-----------------------------------------+
| compileOnly        | Declaring compile    |     yes     |      yes     | This is where you should                |
|                    | only                 |             |              | declare dependencies                    |
|                    | dependencies         |             |              | which are only required                 |
|                    |                      |             |              | at compile time, but should             |
|                    |                      |             |              | not leak into the runtime.              |
|                    |                      |             |              | This typically includes dependencies    |
|                    |                      |             |              | which are shaded when found at runtime. |
+--------------------+----------------------+-------------+--------------+-----------------------------------------+
| runtimeOnly        | Declaring            |      no     |      no      | This is where you should                |
|                    | runtime              |             |              | declare dependencies which              |
|                    | dependencies         |             |              | are only required at runtime,           |
|                    |                      |             |              | and not at compile time.                |
+--------------------+----------------------+-------------+--------------+-----------------------------------------+
| testImplementation | Test dependencies    |      no     |      no      | This is where you                       |
|                    |                      |             |              | should declare dependencies             |
|                    |                      |             |              | which are used to compile tests.        |
+--------------------+----------------------+-------------+--------------+-----------------------------------------+
| testCompileOnly    | Declaring test       |     yes     |      yes     | This is where you should                |
|                    | compile only         |             |              | declare dependencies                    |
|                    | dependencies         |             |              | which are only required                 |
|                    |                      |             |              | at test compile time,                   |
|                    |                      |             |              | but should not leak into the runtime.   |
|                    |                      |             |              | This typically includes dependencies    |
|                    |                      |             |              | which are shaded when found at runtime. |
+--------------------+----------------------+-------------+--------------+-----------------------------------------+
| testRuntimeOnly    | Declaring test       |      no     |      no      | This is where you should                |
|                    | runtime dependencies |             |              | declare dependencies which              |
|                    |                      |             |              | are only required at test               |
|                    |                      |             |              | runtime, and not at test compile time.  |
+--------------------+----------------------+-------------+--------------+-----------------------------------------+

Safe Area of Xcode 9

The Safe Area Layout Guide helps avoid underlapping System UI elements when positioning content and controls.

The Safe Area is the area in between System UI elements which are Status Bar, Navigation Bar and Tool Bar or Tab Bar. So when you add a Status bar to your app, the Safe Area shrink. When you add a Navigation Bar to your app, the Safe Area shrinks again.

On the iPhone X, the Safe Area provides additional inset from the top and bottom screen edges in portrait even when no bar is shown. In landscape, the Safe Area is inset from the sides of the screens and the home indicator.

This is taken from Apple's video Designing for iPhone X where they also visualize how different elements affect the Safe Area.

Show/hide widgets in Flutter programmatically

UPDATE: Since this answer was written, Visibility was introduced and provides the best solution to this problem.


You can use Opacity with an opacity: of 0.0 to draw make an element hidden but still occupy space.

To make it not occupy space, replace it with an empty Container().

EDIT: To wrap it in an Opacity object, do the following:

            new Opacity(opacity: 0.0, child: new Padding(
              padding: const EdgeInsets.only(
                left: 16.0,
              ),
              child: new Icon(pencil, color: CupertinoColors.activeBlue),
            ))

Google Developers quick tutorial on Opacity: https://youtu.be/9hltevOHQBw

Equal height rows in CSS Grid Layout

The short answer is that setting grid-auto-rows: 1fr; on the grid container solves what was asked.

https://codepen.io/Hlsg/pen/EXKJba

Bootstrap 4: Multilevel Dropdown Inside Navigation

Using official HTML without adding extra CSS styles and classes, it's like native support.

Just add the following code:

$.fn.dropdown = (function() {
    var $bsDropdown = $.fn.dropdown;
    return function(config) {
        if (typeof config === 'string' && config === 'toggle') { // dropdown toggle trigged
            $('.has-child-dropdown-show').removeClass('has-child-dropdown-show');
            $(this).closest('.dropdown').parents('.dropdown').addClass('has-child-dropdown-show');
        }
        var ret = $bsDropdown.call($(this), config);
        $(this).off('click.bs.dropdown'); // Turn off dropdown.js click event, it will call 'this.toggle()' internal
        return ret;
    }
})();

$(function() {
    $('.dropdown [data-toggle="dropdown"]').on('click', function(e) {
        $(this).dropdown('toggle');
        e.stopPropagation();
    });
    $('.dropdown').on('hide.bs.dropdown', function(e) {
        if ($(this).is('.has-child-dropdown-show')) {
            $(this).removeClass('has-child-dropdown-show');
            e.preventDefault();
        }
        e.stopPropagation();
    });
});

Dropdown of bootstrap can be easily changed to infinite level. It's a pity that they didn't do it.

BTW, a hover version: https://github.com/dallaslu/bootstrap-4-multi-level-dropdown

Here is a perfect demo: https://jsfiddle.net/dallaslu/adky6jvs/ (works well with Bootstrap v4.4.1)

Get Path from another app (WhatsApp)

you can try to this , then you get a bitmap of selected image and then you can easily find it's native path from Device Default Gallery.

Bitmap roughBitmap= null;
    try {
    // Works with content://, file://, or android.resource:// URIs
    InputStream inputStream =
    getContentResolver().openInputStream(uri);
    roughBitmap= BitmapFactory.decodeStream(inputStream);

    // calc exact destination size
    Matrix m = new Matrix();
    RectF inRect = new RectF(0, 0, roughBitmap.Width, roughBitmap.Height);
    RectF outRect = new RectF(0, 0, dstWidth, dstHeight);
    m.SetRectToRect(inRect, outRect, Matrix.ScaleToFit.Center);
    float[] values = new float[9];
    m.GetValues(values);


    // resize bitmap if needed
    Bitmap resizedBitmap = Bitmap.CreateScaledBitmap(roughBitmap, (int) (roughBitmap.Width * values[0]), (int) (roughBitmap.Height * values[4]), true);

    string name = "IMG_" + new Java.Text.SimpleDateFormat("yyyyMMdd_HHmmss").Format(new Java.Util.Date()) + ".png";
    var sdCardPath= Environment.GetExternalStoragePublicDirectory("DCIM").AbsolutePath;
    Java.IO.File file = new Java.IO.File(sdCardPath);
    if (!file.Exists())
    {
        file.Mkdir();
    }
    var filePath = System.IO.Path.Combine(sdCardPath, name);
    } catch (FileNotFoundException e) {
    // Inform the user that things have gone horribly wrong
    }

Failed to load AppCompat ActionBar with unknown error in android studio

in android 3.0.0 canary 6 you must change all 2.6.0 beta2 to beta1 (appcompat,design,supportvector)

Enums in Javascript with ES6

Here is my implementation of a Java enumeration in JavaScript.

I also included unit tests.

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const main = () => {
  mocha.setup('bdd')
  chai.should()

  describe('Test Color [From Array]', function() {
    let Color = new Enum('RED', 'BLUE', 'GREEN')
    
    it('Test: Color.values()', () => {
      Color.values().length.should.equal(3)
    })

    it('Test: Color.RED', () => {
      chai.assert.isNotNull(Color.RED)
    })

    it('Test: Color.BLUE', () => {
      chai.assert.isNotNull(Color.BLUE)
    })

    it('Test: Color.GREEN', () => {
      chai.assert.isNotNull(Color.GREEN)
    })

    it('Test: Color.YELLOW', () => {
      chai.assert.isUndefined(Color.YELLOW)
    })
  })

  describe('Test Color [From Object]', function() {
    let Color = new Enum({
      RED   : { hex: '#F00' },
      BLUE  : { hex: '#0F0' },
      GREEN : { hex: '#00F' }
    })

    it('Test: Color.values()', () => {
      Color.values().length.should.equal(3)
    })

    it('Test: Color.RED', () => {
      let red = Color.RED
      chai.assert.isNotNull(red)
      red.getHex().should.equal('#F00')
    })

    it('Test: Color.BLUE', () => {
      let blue = Color.BLUE
      chai.assert.isNotNull(blue)
      blue.getHex().should.equal('#0F0')
    })

    it('Test: Color.GREEN', () => {
      let green = Color.GREEN
      chai.assert.isNotNull(green)
      green.getHex().should.equal('#00F')
    })

    it('Test: Color.YELLOW', () => {
      let yellow = Color.YELLOW
      chai.assert.isUndefined(yellow)
    })
  })

  mocha.run()
}

class Enum {
  constructor(values) {
    this.__values = []
    let isObject = arguments.length === 1
    let args = isObject ? Object.keys(values) : [...arguments]
    args.forEach((name, index) => {
      this.__createValue(name, isObject ? values[name] : null, index)
    })
    Object.freeze(this)
  }

  values() {
    return this.__values
  }

  /* @private */
  __createValue(name, props, index) {
    let value = new Object()
    value.__defineGetter__('name', function() {
      return Symbol(name)
    })
    value.__defineGetter__('ordinal', function() {
      return index
    })
    if (props) {
      Object.keys(props).forEach(prop => {
        value.__defineGetter__(prop, function() {
          return props[prop]
        })
        value.__proto__['get' + this.__capitalize(prop)] = function() {
          return this[prop]
        }
      })
    }
    Object.defineProperty(this, name, {
      value: Object.freeze(value),
      writable: false
    })
    this.__values.push(this[name])
  }

  /* @private */
  __capitalize(str) {
    return str.charAt(0).toUpperCase() + str.slice(1)
  }
}

main()
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.as-console-wrapper { top: 0; max-height: 100% !important; }
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<link rel="stylesheet" type="text/css" href="https://cdnjs.cloudflare.com/ajax/libs/mocha/2.2.5/mocha.css">
<script type="text/javascript" src="https://cdnjs.cloudflare.com/ajax/libs/mocha/2.2.5/mocha.js"></script>
<script type="text/javascript" src="https://cdnjs.cloudflare.com/ajax/libs/chai/3.2.0/chai.js"></script>
<!--

public enum Color {
  RED("#F00"),
  BLUE("#0F0"),
  GREEN("#00F");
  
  private String hex;
  public String getHex()  { return this.hex;  }
  
  private Color(String hex) {
    this.hex = hex;
  }
}

-->
<div id="mocha"></div>
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Update

Here is a more up-to-date version that satisfies MDN.

The Object.prototype.__defineGetter__ has been replaced by Object.defineProperty per MDN's recomendation:

This feature is deprecated in favor of defining getters using the object initializer syntax or the Object.defineProperty() API. While this feature is widely implemented, it is only described in the ECMAScript specification because of legacy usage. This method should not be used since better alternatives exist.

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const main = () => {
  mocha.setup('bdd')
  chai.should()

  describe('Test Color [From Array]', function() {
    let Color = new Enum('RED', 'BLUE', 'GREEN')

    it('Test: Color.values()', () => {
      Color.values().length.should.equal(3)
    })

    it('Test: Color.RED', () => {
      chai.assert.isNotNull(Color.RED)
    })

    it('Test: Color.BLUE', () => {
      chai.assert.isNotNull(Color.BLUE)
    })

    it('Test: Color.GREEN', () => {
      chai.assert.isNotNull(Color.GREEN)
    })

    it('Test: Color.YELLOW', () => {
      chai.assert.isUndefined(Color.YELLOW)
    })
  })

  describe('Test Color [From Object]', function() {
    let Color = new Enum({
      RED:   { hex: '#F00' },
      BLUE:  { hex: '#0F0' },
      GREEN: { hex: '#00F' }
    })
    
    it('Test: Color.values()', () => {
      Color.values().length.should.equal(3)
    })

    it('Test: Color.RED', () => {
      let red = Color.RED
      chai.assert.isNotNull(red)
      red.getHex().should.equal('#F00')
    })

    it('Test: Color.BLUE', () => {
      let blue = Color.BLUE
      chai.assert.isNotNull(blue)
      blue.getHex().should.equal('#0F0')
    })

    it('Test: Color.GREEN', () => {
      let green = Color.GREEN
      chai.assert.isNotNull(green)
      green.getHex().should.equal('#00F')
    })

    it('Test: Color.YELLOW', () => {
      let yellow = Color.YELLOW
      chai.assert.isUndefined(yellow)
    })
  })

  mocha.run()
}

class Enum {
  constructor(...values) {
    this.__values = []

    const [first, ...rest] = values
    const hasOne = rest.length === 0
    const isArray = Array.isArray(first)
    const args = hasOne ? (isArray ? first : Object.keys(first)) : values

    args.forEach((name, index) => {
      this.__createValue({
        name,
        index,
        props: hasOne && !isArray ? first[name] : null
      })
    })

    Object.freeze(this)
  }

  /* @public */
  values() {
    return this.__values
  }

  /* @private */
  __createValue({ name, index, props }) {
    const value = {}

    Object.defineProperties(value, Enum.__defineReservedProps({
      name,
      index
    }))

    if (props) {
      Object.defineProperties(value, Enum.__defineAccessors(props))
    }

    Object.defineProperty(this, name, {
      value: Object.freeze(value),
      writable: false
    })

    this.__values.push(this[name])
  }
}

/* @private */
Enum.__defineReservedProps = ({ name, index }) => ({
  name: {
    value: Symbol(name),
    writable: false
  },
  ordinal: {
    value: index,
    writable: false
  }
})

/* @private */
Enum.__defineAccessors = (props) =>
  Object.entries(props).reduce((acc, [prop, val]) => ({
    ...acc,
    [prop]: {
      value: val,
      writable: false
    },
    [`get${Enum.__capitalize(prop)}`]: {
      get: () => function() {
        return this[prop]
      }
    }
  }), {})

/* @private */
Enum.__capitalize = (str) => str.charAt(0).toUpperCase() + str.slice(1)

main()
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.as-console-wrapper { top: 0; max-height: 100% !important; }
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<link rel="stylesheet" type="text/css" href="https://cdnjs.cloudflare.com/ajax/libs/mocha/2.2.5/mocha.css">
<script type="text/javascript" src="https://cdnjs.cloudflare.com/ajax/libs/mocha/2.2.5/mocha.js"></script>
<script type="text/javascript" src="https://cdnjs.cloudflare.com/ajax/libs/chai/3.2.0/chai.js"></script>
<!--

public enum Color {
  RED("#F00"),
  BLUE("#0F0"),
  GREEN("#00F");
  
  private String hex;
  public String getHex()  { return this.hex;  }
  
  private Color(String hex) {
    this.hex = hex;
  }
}

-->
<div id="mocha"></div>
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AttributeError: module 'cv2.cv2' has no attribute 'createLBPHFaceRecognizer'

You might be running Python3 and therefore you are supposed to use pip3 to install the opencv-contrib package :

pip3 install opencv-contrib-python

This worked for me.

What is a 'workspace' in Visual Studio Code?

The title and subsequent question in the OP seem to boil down to:

  1. What is a workspace in VS Code?
  2. How do workspace settings work?

Short answer:

A workspace is a virtual collection of folders opened simultaneously in VSCode and defined in a .code-workspace file. Opening this file will open the collection of folders automatically. This is called a "multi-root" workspace.

The .code-workspace file also defines workspace settings that are used by the instance of VSCode where the workspace is opened.

When a workspace is not defined, i.e. you open a folder on its own, you can create "workspace settings" that are saved in a .vscode\settings.json file in the root of that folder structure.


In more detail:

VSCode uses the word "workspace" a little ambiguously in places. The first use to consider is in what is calls a multi-root workspace.

A multi-root workspace is a set of folders (the "roots") that are opened collectively in an instance of VSCode. There is no need for these folders to share parent folders; indeed that is the point since VSCode normally uses a single folder in the Explorer side-bar.

A multi-root workspace is defined by a .code-workspace (JSON) file which contains both the list of folders to be included in the workspace and VSCode settings.

Regarding those workspace settings...

When you open File > Preferences > Settings the settings editor is shown. At the very least you should see a USER SETTINGS tab. These are the VSCode settings that are universal for your user account on your local machine. In Windows these are saved in %APPDATA%\Code\User\settings.json.

Individual folders (often each of the "root" folders in a workspace) might have a .vscode folder with their own settings.json file. When opened individually, i.e. not as part of a workspace, the content of these settings.json files is presented under the WORKSPACE SETTINGS tab, and ALL the settings in that file are used by the running VSCode instance.

When opening a multi-root workspace things behave differently. Firstly, the WORKSPACE SETTINGS tab shows the options set in the .code-workspace file. Secondly, any folder with a settings.json file will appear under a new FOLDER SETTINGS tab. Be aware that, when in a multi-root workspace, only a limited number of settings from each folder's settings.json are used. I suggest you open the link above to read further.

How to find count of Null and Nan values for each column in a PySpark dataframe efficiently?

I prefer this solution:

df = spark.table(selected_table).filter(condition)

counter = df.count()

df = df.select([(counter - count(c)).alias(c) for c in df.columns])

Passing headers with axios POST request

Here is a full example of an axios.post request with custom headers

_x000D_
_x000D_
var postData = {_x000D_
  email: "[email protected]",_x000D_
  password: "password"_x000D_
};_x000D_
_x000D_
let axiosConfig = {_x000D_
  headers: {_x000D_
      'Content-Type': 'application/json;charset=UTF-8',_x000D_
      "Access-Control-Allow-Origin": "*",_x000D_
  }_x000D_
};_x000D_
_x000D_
axios.post('http://<host>:<port>/<path>', postData, axiosConfig)_x000D_
.then((res) => {_x000D_
  console.log("RESPONSE RECEIVED: ", res);_x000D_
})_x000D_
.catch((err) => {_x000D_
  console.log("AXIOS ERROR: ", err);_x000D_
})
_x000D_
_x000D_
_x000D_

Vue Js - Loop via v-for X times (in a range)

You can use the native JS slice method:

<div v-for="item in shoppingItems.slice(0,10)">

The slice() method returns the selected elements in an array, as a new array object.

Based on tip in the migration guide: https://vuejs.org/v2/guide/migration.html#Replacing-the-limitBy-Filter

How to fix Cannot find module 'typescript' in Angular 4?

I had the same problem. If you have installed first nodejs by apt and then you use the tar.gz from nodejs.org, you have to delete the folder located in /usr/lib/node_modules.

How to completely uninstall python 2.7.13 on Ubuntu 16.04

This is what I have after doing purge of all the python versions and reinstalling only 3.6.

root@esp32:/# python
Python 3.6.0b2 (default, Oct 11 2016, 05:27:10) 
[GCC 6.2.0 20161005] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> 
root@esp32:/# python3
Python 3.8.0 (default, Dec 15 2019, 14:19:02) 
[GCC 6.2.0 20161005] on linux
Type "help", "copyright", "credits" or "license" for more information.

Also the pip and pip3 commands are totally f up:

root@esp32:/# pip
Traceback (most recent call last):
  File "/usr/local/bin/pip", line 7, in <module>
    from pip._internal.cli.main import main
  File "/usr/local/lib/python3.5/dist-packages/pip/_internal/cli/main.py", line 60
    sys.stderr.write(f"ERROR: {exc}")
                                   ^
SyntaxError: invalid syntax

root@esp32:/# pip3
Traceback (most recent call last):
  File "/usr/local/bin/pip3", line 7, in <module>
    from pip._internal.cli.main import main
  File "/usr/local/lib/python3.5/dist-packages/pip/_internal/cli/main.py", line 60
    sys.stderr.write(f"ERROR: {exc}")
                                   ^
SyntaxError: invalid syntax

I am totally noob at Linux, I just wanted to update Python from 2.x to 3.x so that Platformio could upgrade and now I messed up everything it seems.

Conda command is not recognized on Windows 10

The newest version of the Anaconda installer for Windows will also install a windows launcher for "Anaconda Prompt" and "Anaconda Powershell Prompt". If you use one of those instead of the regular windows cmd shell, the conda command, python etc. should be available by default in this shell.

enter image description here

How to convert JSON string into List of Java object?

You are asking Jackson to parse a StudentList. Tell it to parse a List (of students) instead. Since List is generic you will typically use a TypeReference

List<Student> participantJsonList = mapper.readValue(jsonString, new TypeReference<List<Student>>(){});

com.apple.WebKit.WebContent drops 113 error: Could not find specified service

Deleting/commenting

- (void)viewWillAppear:(BOOL)animated {[super viewWillAppear:YES];}

function solved the problem for me.

XCode (11.3.1)

How to listen for 'props' changes

@JoeSchr has an answer. Here is another way to do if you don't want deep: true

 mounted() {
    this.yourMethod();
    // re-render any time a prop changes
    Object.keys(this.$options.props).forEach(key => {
      this.$watch(key, this.yourMethod);
    });
  },

How to remove docker completely from ubuntu 14.04

Probably your problem is that for Docker that has been installed from default Ubuntu repository, the package name is docker.io

Or package name may be something like docker-ce. Try running

dpkg -l | grep -i docker

to identify what installed package you have

So you need to change package name in commands from https://stackoverflow.com/a/31313851/2340159 to match package name. For example, for docker.io it would be:

sudo apt-get purge -y docker.io
sudo apt-get autoremove -y --purge docker.io
sudo apt-get autoclean

It adds:

The above commands will not remove images, containers, volumes, or user created configuration files on your host. If you wish to delete all images, containers, and volumes run the following command:

sudo rm -rf /var/lib/docker

Remove docker from apparmor.d:

sudo rm /etc/apparmor.d/docker

Remove docker group:

sudo groupdel docker

Keras input explanation: input_shape, units, batch_size, dim, etc

Units:

The amount of "neurons", or "cells", or whatever the layer has inside it.

It's a property of each layer, and yes, it's related to the output shape (as we will see later). In your picture, except for the input layer, which is conceptually different from other layers, you have:

  • Hidden layer 1: 4 units (4 neurons)
  • Hidden layer 2: 4 units
  • Last layer: 1 unit

Shapes

Shapes are consequences of the model's configuration. Shapes are tuples representing how many elements an array or tensor has in each dimension.

Ex: a shape (30,4,10) means an array or tensor with 3 dimensions, containing 30 elements in the first dimension, 4 in the second and 10 in the third, totaling 30*4*10 = 1200 elements or numbers.

The input shape

What flows between layers are tensors. Tensors can be seen as matrices, with shapes.

In Keras, the input layer itself is not a layer, but a tensor. It's the starting tensor you send to the first hidden layer. This tensor must have the same shape as your training data.

Example: if you have 30 images of 50x50 pixels in RGB (3 channels), the shape of your input data is (30,50,50,3). Then your input layer tensor, must have this shape (see details in the "shapes in keras" section).

Each type of layer requires the input with a certain number of dimensions:

  • Dense layers require inputs as (batch_size, input_size)
    • or (batch_size, optional,...,optional, input_size)
  • 2D convolutional layers need inputs as:
    • if using channels_last: (batch_size, imageside1, imageside2, channels)
    • if using channels_first: (batch_size, channels, imageside1, imageside2)
  • 1D convolutions and recurrent layers use (batch_size, sequence_length, features)

Now, the input shape is the only one you must define, because your model cannot know it. Only you know that, based on your training data.

All the other shapes are calculated automatically based on the units and particularities of each layer.

Relation between shapes and units - The output shape

Given the input shape, all other shapes are results of layers calculations.

The "units" of each layer will define the output shape (the shape of the tensor that is produced by the layer and that will be the input of the next layer).

Each type of layer works in a particular way. Dense layers have output shape based on "units", convolutional layers have output shape based on "filters". But it's always based on some layer property. (See the documentation for what each layer outputs)

Let's show what happens with "Dense" layers, which is the type shown in your graph.

A dense layer has an output shape of (batch_size,units). So, yes, units, the property of the layer, also defines the output shape.

  • Hidden layer 1: 4 units, output shape: (batch_size,4).
  • Hidden layer 2: 4 units, output shape: (batch_size,4).
  • Last layer: 1 unit, output shape: (batch_size,1).

Weights

Weights will be entirely automatically calculated based on the input and the output shapes. Again, each type of layer works in a certain way. But the weights will be a matrix capable of transforming the input shape into the output shape by some mathematical operation.

In a dense layer, weights multiply all inputs. It's a matrix with one column per input and one row per unit, but this is often not important for basic works.

In the image, if each arrow had a multiplication number on it, all numbers together would form the weight matrix.

Shapes in Keras

Earlier, I gave an example of 30 images, 50x50 pixels and 3 channels, having an input shape of (30,50,50,3).

Since the input shape is the only one you need to define, Keras will demand it in the first layer.

But in this definition, Keras ignores the first dimension, which is the batch size. Your model should be able to deal with any batch size, so you define only the other dimensions:

input_shape = (50,50,3)
    #regardless of how many images I have, each image has this shape        

Optionally, or when it's required by certain kinds of models, you can pass the shape containing the batch size via batch_input_shape=(30,50,50,3) or batch_shape=(30,50,50,3). This limits your training possibilities to this unique batch size, so it should be used only when really required.

Either way you choose, tensors in the model will have the batch dimension.

So, even if you used input_shape=(50,50,3), when keras sends you messages, or when you print the model summary, it will show (None,50,50,3).

The first dimension is the batch size, it's None because it can vary depending on how many examples you give for training. (If you defined the batch size explicitly, then the number you defined will appear instead of None)

Also, in advanced works, when you actually operate directly on the tensors (inside Lambda layers or in the loss function, for instance), the batch size dimension will be there.

  • So, when defining the input shape, you ignore the batch size: input_shape=(50,50,3)
  • When doing operations directly on tensors, the shape will be again (30,50,50,3)
  • When keras sends you a message, the shape will be (None,50,50,3) or (30,50,50,3), depending on what type of message it sends you.

Dim

And in the end, what is dim?

If your input shape has only one dimension, you don't need to give it as a tuple, you give input_dim as a scalar number.

So, in your model, where your input layer has 3 elements, you can use any of these two:

  • input_shape=(3,) -- The comma is necessary when you have only one dimension
  • input_dim = 3

But when dealing directly with the tensors, often dim will refer to how many dimensions a tensor has. For instance a tensor with shape (25,10909) has 2 dimensions.


Defining your image in Keras

Keras has two ways of doing it, Sequential models, or the functional API Model. I don't like using the sequential model, later you will have to forget it anyway because you will want models with branches.

PS: here I ignored other aspects, such as activation functions.

With the Sequential model:

from keras.models import Sequential  
from keras.layers import *  

model = Sequential()    

#start from the first hidden layer, since the input is not actually a layer   
#but inform the shape of the input, with 3 elements.    
model.add(Dense(units=4,input_shape=(3,))) #hidden layer 1 with input

#further layers:    
model.add(Dense(units=4)) #hidden layer 2
model.add(Dense(units=1)) #output layer   

With the functional API Model:

from keras.models import Model   
from keras.layers import * 

#Start defining the input tensor:
inpTensor = Input((3,))   

#create the layers and pass them the input tensor to get the output tensor:    
hidden1Out = Dense(units=4)(inpTensor)    
hidden2Out = Dense(units=4)(hidden1Out)    
finalOut = Dense(units=1)(hidden2Out)   

#define the model's start and end points    
model = Model(inpTensor,finalOut)

Shapes of the tensors

Remember you ignore batch sizes when defining layers:

  • inpTensor: (None,3)
  • hidden1Out: (None,4)
  • hidden2Out: (None,4)
  • finalOut: (None,1)

Specifying ssh key in ansible playbook file

The variable name you're looking for is ansible_ssh_private_key_file.

You should set it at 'vars' level:

  • in the inventory file:

    myHost ansible_ssh_private_key_file=~/.ssh/mykey1.pem
    myOtherHost ansible_ssh_private_key_file=~/.ssh/mykey2.pem
    
  • in the host_vars:

    # hosts_vars/myHost.yml
    ansible_ssh_private_key_file: ~/.ssh/mykey1.pem
    
    # hosts_vars/myOtherHost.yml
    ansible_ssh_private_key_file: ~/.ssh/mykey2.pem
    
  • in a group_vars file if you use the same key for a group of hosts

  • in the vars section of your play:

    - hosts: myHost
      remote_user: ubuntu
      vars_files:
        - vars.yml
      vars:
        ansible_ssh_private_key_file: "{{ key1 }}"
      tasks:
        - name: Echo a hello message
          command: echo hello
    

Inventory documentation

Set value to an entire column of a pandas dataframe

Seems to me that:

df1 = df[df['col1']==some_value] WILL NOT create a new DataFrame, basically, changes in df1 will be reflected in the parent df. This leads to the warning. Whereas, df1 = df[df['col1]]==some_value].copy() WILL create a new DataFrame, and changes in df1 will not be reflected in df. the copy() method is recommended if you don't want to make changes to your original df.

Java.lang.NoClassDefFoundError: com/fasterxml/jackson/databind/exc/InvalidDefinitionException

Use all the jackson dependencies(databind,core, annotations, scala(if you are using spark and scala)) with the same version.. and upgrade the versions to the latest releases..

<dependency>
            <groupId>com.fasterxml.jackson.module</groupId>
            <artifactId>jackson-module-scala_2.11</artifactId>
            <version>2.9.4</version>
        </dependency>

        <dependency>
        <groupId>com.fasterxml.jackson.core</groupId>
        <artifactId>jackson-databind</artifactId>
        <version>2.9.4</version>
        <exclusions>
            <exclusion>
                <groupId>com.fasterxml.jackson.core</groupId>
                <artifactId>jackson-core</artifactId>
            </exclusion>
            <exclusion>
                <groupId>com.fasterxml.jackson.core</groupId>
                <artifactId>jackson-annotations</artifactId>
            </exclusion>
        </exclusions>
    </dependency>
    <dependency>
        <groupId>com.fasterxml.jackson.core</groupId>
        <artifactId>jackson-core</artifactId>
        <version>2.9.4</version>
    </dependency>

        <dependency>
        <groupId>com.fasterxml.jackson.core</groupId>
        <artifactId>jackson-annotations</artifactId>
        <version>2.9.4</version>

        </dependency>

Note: Use Scala dependency only if you are working with scala. Otherwise it is not needed.

Kubernetes Pod fails with CrashLoopBackOff

Pod is not started due to problem coming after initialization of POD.

Check and use command to get docker container of pod

docker ps -a | grep private-reg

Output will be information of docker container with id.

See docker logs:

docker logs -f <container id>

Hide header in stack navigator React navigation

 <Stack.Screen
    name="SignInScreen"
    component={Screens.SignInScreen}
    options={{ headerShown: false }}
  />

options={{ headerShown: false }} works for me.

** "@react-navigation/native": "^5.0.7", "@react-navigation/stack": "^5.0.8",

How to completely uninstall kubernetes

In my "Ubuntu 16.04", I use next steps to completely remove and clean Kubernetes (installed with "apt-get"):

kubeadm reset
sudo apt-get purge kubeadm kubectl kubelet kubernetes-cni kube*   
sudo apt-get autoremove  
sudo rm -rf ~/.kube

And restart the computer.

TypeError: Object of type 'bytes' is not JSON serializable

I was dealing with this issue today, and I knew that I had something encoded as a bytes object that I was trying to serialize as json with json.dump(my_json_object, write_to_file.json). my_json_object in this case was a very large json object that I had created, so I had several dicts, lists, and strings to look at to find what was still in bytes format.

The way I ended up solving it: the write_to_file.json will have everything up to the bytes object that is causing the issue.

In my particular case this was a line obtained through

for line in text:
    json_object['line'] = line.strip()

I solved by first finding this error with the help of the write_to_file.json, then by correcting it to:

for line in text:
    json_object['line'] = line.strip().decode()

How do I fix maven error The JAVA_HOME environment variable is not defined correctly?

The SETX command does not modify the current environment.

If you run the following batch file:

setx AAA aaa
echo AAA=%AAA%

It will print

AAA=

So your batch file is wrong. You have to use set:

set AAA=aaa

See What is the difference between SETX and SET in environment variables in Windows.

Cannot connect to the Docker daemon at unix:/var/run/docker.sock. Is the docker daemon running?

It's worked for me:

sudo systemctl unmask docker
sudo systemctl start docker

How to send json data in POST request using C#

You can use either HttpClient or RestSharp. Since I do not know what your code is, here is an example using HttpClient:

using (var client = new HttpClient())
{
    // This would be the like http://www.uber.com
    client.BaseAddress = new Uri("Base Address/URL Address");

    // serialize your json using newtonsoft json serializer then add it to the StringContent
    var content = new StringContent(YourJson, Encoding.UTF8, "application/json") 

    // method address would be like api/callUber:SomePort for example
    var result = await client.PostAsync("Method Address", content);
    string resultContent = await result.Content.ReadAsStringAsync();   
}

'ng' is not recognized as an internal or external command, operable program or batch file

If angular cli is installed and ng command is not working then please see below suggestion, it may work

In my case problem was with npm config file (.npmrc ) which is available at C:\Users{user}. That file does not contain line registry https://registry.npmjs.org/=true. When i have added that line command started working. Use below command to edit config file. Edit file and save. Try to run command again. It should work now.

npm config edit

How to truncate text in Angular2?

Here's an alternative approach using an interface to describe the shape of an options object to be passed via the pipe in the markup.

@Pipe({
  name: 'textContentTruncate'
})
export class TextContentTruncatePipe implements PipeTransform {

  transform(textContent: string, options: TextTruncateOptions): string {
    if (textContent.length >= options.sliceEnd) {
      let truncatedText = textContent.slice(options.sliceStart, options.sliceEnd);
      if (options.prepend) { truncatedText = `${options.prepend}${truncatedText}`; }
      if (options.append) { truncatedText = `${truncatedText}${options.append}`; }
      return truncatedText;
    }
    return textContent;
  }

}

interface TextTruncateOptions {
  sliceStart: number;
  sliceEnd: number;
  prepend?: string;
  append?: string;
}

Then in your markup:

{{someText | textContentTruncate:{sliceStart: 0, sliceEnd: 50, append: '...'} }}

Vue component event after render

updated() should be what you're looking for:

Called after a data change causes the virtual DOM to be re-rendered and patched.

The component’s DOM will have been updated when this hook is called, so you can perform DOM-dependent operations here.

Android dependency has different version for the compile and runtime

You should be able to see exactly which dependency is pulling in the odd version as a transitive dependency by running the correct gradle -q dependencies command for your project as described here:

https://docs.gradle.org/current/userguide/userguide_single.html#sec:listing_dependencies

Once you track down what's pulling it in, you can add an exclude to that specific dependency in your gradle file with something like:

implementation("XXXXX") {
    exclude group: 'com.android.support', module: 'support-compat'
}

How to run shell script file using nodejs?

You can execute any shell command using the shelljs module

 const shell = require('shelljs')

 shell.exec('./path_to_your_file')

How to know Laravel version and where is it defined?

In your Laravel deployment it would be

/vendor/laravel/framework/src/Illuminate/Foundation/Application.php

to see who changed your Laravel version look at what's defined in composer.json. If you have "laravel/framework": "5.4.*", then it will update to the latest after composer update is run. Composer.lock is the file that results from running a composer update, so really see who last one to modify the composer.json file was (hopefully you have that in version control). You can read more about it here https://getcomposer.org/doc/01-basic-usage.md

Python error message io.UnsupportedOperation: not readable

Use a+ to open a file for reading, writing as well as create it if it doesn't exist.

a+ Opens a file for both appending and reading. The file pointer is at the end of the file if the file exists. The file opens in the append mode. If the file does not exist, it creates a new file for reading and writing. -Python file modes

with open('"File.txt', 'a+') as file:
    print(file.readlines())
    file.write("test")

Note: opening file in a with block makes sure that the file is properly closed at the block's end, even if an exception is raised on the way. It's equivalent to try-finally, but much shorter.

Selection with .loc in python

pd.DataFrame.loc can take one or two indexers. For the rest of the post, I'll represent the first indexer as i and the second indexer as j.

If only one indexer is provided, it applies to the index of the dataframe and the missing indexer is assumed to represent all columns. So the following two examples are equivalent.

  1. df.loc[i]
  2. df.loc[i, :]

Where : is used to represent all columns.

If both indexers are present, i references index values and j references column values.


Now we can focus on what types of values i and j can assume. Let's use the following dataframe df as our example:

    df = pd.DataFrame([[1, 2], [3, 4]], index=['A', 'B'], columns=['X', 'Y'])

loc has been written such that i and j can be

  1. scalars that should be values in the respective index objects

    df.loc['A', 'Y']
    
    2
    
  2. arrays whose elements are also members of the respective index object (notice that the order of the array I pass to loc is respected

    df.loc[['B', 'A'], 'X']
    
    B    3
    A    1
    Name: X, dtype: int64
    
    • Notice the dimensionality of the return object when passing arrays. i is an array as it was above, loc returns an object in which an index with those values is returned. In this case, because j was a scalar, loc returned a pd.Series object. We could've manipulated this to return a dataframe if we passed an array for i and j, and the array could've have just been a single value'd array.

      df.loc[['B', 'A'], ['X']]
      
         X
      B  3
      A  1
      
  3. boolean arrays whose elements are True or False and whose length matches the length of the respective index. In this case, loc simply grabs the rows (or columns) in which the boolean array is True.

    df.loc[[True, False], ['X']]
    
       X
    A  1
    

In addition to what indexers you can pass to loc, it also enables you to make assignments. Now we can break down the line of code you provided.

iris_data.loc[iris_data['class'] == 'versicolor', 'class'] = 'Iris-versicolor'
  1. iris_data['class'] == 'versicolor' returns a boolean array.
  2. class is a scalar that represents a value in the columns object.
  3. iris_data.loc[iris_data['class'] == 'versicolor', 'class'] returns a pd.Series object consisting of the 'class' column for all rows where 'class' is 'versicolor'
  4. When used with an assignment operator:

    iris_data.loc[iris_data['class'] == 'versicolor', 'class'] = 'Iris-versicolor'
    

    We assign 'Iris-versicolor' for all elements in column 'class' where 'class' was 'versicolor'

Angular 4: InvalidPipeArgument: '[object Object]' for pipe 'AsyncPipe'

You should add the pipe to the interpolation and not to the ngFor

ul
  li(*ngFor='let movie of (movies)') ///////////removed here///////////////////
    | {{ movie.title | async }}

Reference docs

Send data through routing paths in Angular

In navigateExtra we can pass only some specific name as argument otherwise it showing error like below: For Ex- Here I want to pass customer key in router navigate and I pass like this-

this.Router.navigate(['componentname'],{cuskey: {customerkey:response.key}});

but it showing some error like below:

Argument of type '{ cuskey: { customerkey: any; }; }' is not assignable to parameter of type 'NavigationExtras'.
  Object literal may only specify known properties, and 'cuskey' does not exist in type 'NavigationExt## Heading ##ras'

.

Solution: we have to write like this:

this.Router.navigate(['componentname'],{state: {customerkey:response.key}});

Select row on click react-table

There is a HOC included for React-Table that allows for selection, even when filtering and paginating the table, the setup is slightly more advanced than the basic table so read through the info in the link below first.


enter image description here



After importing the HOC you can then use it like this with the necessary methods:

/**
* Toggle a single checkbox for select table
*/
toggleSelection(key: number, shift: string, row: string) {
    // start off with the existing state
    let selection = [...this.state.selection];
    const keyIndex = selection.indexOf(key);

    // check to see if the key exists
    if (keyIndex >= 0) {
        // it does exist so we will remove it using destructing
        selection = [
            ...selection.slice(0, keyIndex),
            ...selection.slice(keyIndex + 1)
        ];
    } else {
        // it does not exist so add it
        selection.push(key);
    }
    // update the state
    this.setState({ selection });
}

/**
* Toggle all checkboxes for select table
*/
toggleAll() {
    const selectAll = !this.state.selectAll;
    const selection = [];

    if (selectAll) {
        // we need to get at the internals of ReactTable
        const wrappedInstance = this.checkboxTable.getWrappedInstance();
        // the 'sortedData' property contains the currently accessible records based on the filter and sort
        const currentRecords = wrappedInstance.getResolvedState().sortedData;
        // we just push all the IDs onto the selection array
        currentRecords.forEach(item => {
            selection.push(item._original._id);
        });
    }
    this.setState({ selectAll, selection });
}

/**
* Whether or not a row is selected for select table
*/
isSelected(key: number) {
    return this.state.selection.includes(key);
}

<CheckboxTable
    ref={r => (this.checkboxTable = r)}
    toggleSelection={this.toggleSelection}
    selectAll={this.state.selectAll}
    toggleAll={this.toggleAll}
    selectType="checkbox"
    isSelected={this.isSelected}
    data={data}
    columns={columns}
/>

See here for more information:
https://github.com/tannerlinsley/react-table/tree/v6#selecttable

Here is a working example:
https://codesandbox.io/s/react-table-select-j9jvw

Anaconda Installed but Cannot Launch Navigator

Try restarting the system! You will be able to find the navigator once you restart the system after installation.

(change) vs (ngModelChange) in angular

(change) event bound to classical input change event.

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

You can use (change) event even if you don't have a model at your input as

<input (change)="somethingChanged()">

(ngModelChange) is the @Output of ngModel directive. It fires when the model changes. You cannot use this event without ngModel directive.

https://github.com/angular/angular/blob/master/packages/forms/src/directives/ng_model.ts#L124

As you discover more in the source code, (ngModelChange) emits the new value.

https://github.com/angular/angular/blob/master/packages/forms/src/directives/ng_model.ts#L169

So it means you have ability of such usage:

<input (ngModelChange)="modelChanged($event)">
modelChanged(newObj) {
    // do something with new value
}

Basically, it seems like there is no big difference between two, but ngModel events gains the power when you use [ngValue].

  <select [(ngModel)]="data" (ngModelChange)="dataChanged($event)" name="data">
      <option *ngFor="let currentData of allData" [ngValue]="currentData">
          {{data.name}}
      </option>
  </select>
dataChanged(newObj) {
    // here comes the object as parameter
}

assume you try the same thing without "ngModel things"

<select (change)="changed($event)">
    <option *ngFor="let currentData of allData" [value]="currentData.id">
        {{data.name}}
    </option>
</select>
changed(e){
    // event comes as parameter, you'll have to find selectedData manually
    // by using e.target.data
}

Returning JSON object as response in Spring Boot

you can also use a hashmap for this

@GetMapping
public HashMap<String, Object> get() {
    HashMap<String, Object> map = new HashMap<>();
    map.put("key1", "value1");
    map.put("results", somePOJO);
    return map;
}

No Application Encryption Key Has Been Specified

I had to restart my queue worker using php artisan queue:restart after running php artisan key:generate to get jobs working.

Component is not part of any NgModule or the module has not been imported into your module

Prerequisites: 1. If you have multiple Modules 2. And you are using a component (suppose DemoComponent) from a different module (suppose AModule), in a different module (suppose BModule)

Then Your AModule should be

@NgModule({
  declarations: [DemoComponent],
  imports: [
    CommonModule
  ],
  exports: [AModule]
})
export class AModule{ }

and your BModule should be

@NgModule({
  declarations: [],
  imports: [
    CommonModule, AModule
  ],
  exports: [],
})
export class BModule { }

Multiple conditions in ngClass - Angular 4

<a [ngClass]="{'class1':array.status === 'active','class2':array.status === 'idle','class3':array.status === 'inactive',}">

How do I include a JavaScript script file in Angular and call a function from that script?

Refer the scripts inside the angular-cli.json (angular.json when using angular 6+) file.

"scripts": [
    "../path" 
 ];

then add in typings.d.ts (create this file in src if it does not already exist)

declare var variableName:any;

Import it in your file as

import * as variable from 'variableName';

How to set x axis values in matplotlib python?

The scaling on your example figure is a bit strange but you can force it by plotting the index of each x-value and then setting the ticks to the data points:

import matplotlib.pyplot as plt
x = [0.00001,0.001,0.01,0.1,0.5,1,5]
# create an index for each tick position
xi = list(range(len(x)))
y = [0.945,0.885,0.893,0.9,0.996,1.25,1.19]
plt.ylim(0.8,1.4)
# plot the index for the x-values
plt.plot(xi, y, marker='o', linestyle='--', color='r', label='Square') 
plt.xlabel('x')
plt.ylabel('y') 
plt.xticks(xi, x)
plt.title('compare')
plt.legend() 
plt.show()

How to add empty spaces into MD markdown readme on GitHub?

Instead of using HTML entities like &nbsp; and &emsp; (as others have suggested), you can use the Unicode em space (8195 in UTF-8) directly. Try copy-pasting the following into your README.md. The spaces at the start of the lines are em spaces.

The action of every agent <br />
  into the world <br />
starts <br />
  from their physical selves. <br />

Cloning an array in Javascript/Typescript

It looks like you may have made a mistake as to where you are doing the copy of an Array. Have a look at my explanation below and a slight modification to the code which should work in helping you reset the data to its previous state.

In your example i can see the following taking place:

  • you are doing a request to get generic items
  • after you get the data you set the results to the this.genericItems
  • directly after that you set the backupData as the result

Am i right in thinking you don't want the 3rd point to happen in that order?

Would this be better:

  • you do the data request
  • make a backup copy of what is current in this.genericItems
  • then set genericItems as the result of your request

Try this:

getGenericItems(selected: Item) {
  this.itemService.getGenericItems(selected).subscribe(
    result => {
       // make a backup before you change the genericItems
       this.backupData = this.genericItems.slice();

       // now update genericItems with the results from your request
       this.genericItems = result;
    });
  }

Warning: Use the 'defaultValue' or 'value' props on <select> instead of setting 'selected' on <option>

Use defaultValue and onChange like this

const [myValue, setMyValue] = useState('');

<select onChange={(e) => setMyValue(e.target.value)} defaultValue={props.myprop}>
                    
       <option>Option 1</option>
       <option>Option 2</option>
       <option>Option 3</option>

</select>

Docker: How to delete all local Docker images

Delete without invoking docker:

rm -rf /var/lib/docker

This directly removes all docker images/containers/volumes from the filesystem.

EF Core add-migration Build Failed

In my case, the application was running. Apparently, it needs to be stopped. Weird error message anyways.

Angular CLI - Please add a @NgModule annotation when using latest

The problem is the import of ProjectsListComponent in your ProjectsModule. You should not import that, but add it to the export array, if you want to use it outside of your ProjectsModule.

Other issues are your project routes. You should add these to an exportable variable, otherwise it's not AOT compatible. And you should -never- import the BrowserModule anywhere else but in your AppModule. Use the CommonModule to get access to the *ngIf, *ngFor...etc directives:

@NgModule({
  declarations: [
     ProjectsListComponent
  ],
  imports: [
    CommonModule,
    RouterModule.forChild(ProjectRoutes)
  ],
  exports: [
     ProjectsListComponent
  ]
})

export class ProjectsModule {}

project.routes.ts

export const ProjectRoutes: Routes = [
      { path: 'projects', component: ProjectsListComponent }
]

Angular 4 Pipe Filter

The transform method signature changed somewhere in an RC of Angular 2. Try something more like this:

export class FilterPipe implements PipeTransform {
    transform(items: any[], filterBy: string): any {
        return items.filter(item => item.id.indexOf(filterBy) !== -1);
    }
}

And if you want to handle nulls and make the filter case insensitive, you may want to do something more like the one I have here:

export class ProductFilterPipe implements PipeTransform {

    transform(value: IProduct[], filterBy: string): IProduct[] {
        filterBy = filterBy ? filterBy.toLocaleLowerCase() : null;
        return filterBy ? value.filter((product: IProduct) =>
            product.productName.toLocaleLowerCase().indexOf(filterBy) !== -1) : value;
    }
}

And NOTE: Sorting and filtering in pipes is a big issue with performance and they are NOT recommended. See the docs here for more info: https://angular.io/guide/pipes#appendix-no-filterpipe-or-orderbypipe

Jest spyOn function called

In your test code your are trying to pass App to the spyOn function, but spyOn will only work with objects, not classes. Generally you need to use one of two approaches here:

1) Where the click handler calls a function passed as a prop, e.g.

class App extends Component {

  myClickFunc = () => {
      console.log('clickity clickcty');
      this.props.someCallback();
  }
  render() {
    return (
      <div className="App">
        <div className="App-header">
          <img src={logo} className="App-logo" alt="logo" />
          <h2>Welcome to React</h2>
        </div>
        <p className="App-intro" onClick={this.myClickFunc}>
          To get started, edit <code>src/App.js</code> and save to reload.
        </p>
      </div>
    );
  }
}

You can now pass in a spy function as a prop to the component, and assert that it is called:

describe('my sweet test', () => {
 it('clicks it', () => {
    const spy = jest.fn();
    const app = shallow(<App someCallback={spy} />)
    const p = app.find('.App-intro')
    p.simulate('click')
    expect(spy).toHaveBeenCalled()
 })
})

2) Where the click handler sets some state on the component, e.g.

class App extends Component {
  state = {
      aProperty: 'first'
  }

  myClickFunc = () => {
      console.log('clickity clickcty');
      this.setState({
          aProperty: 'second'
      });
  }
  render() {
    return (
      <div className="App">
        <div className="App-header">
          <img src={logo} className="App-logo" alt="logo" />
          <h2>Welcome to React</h2>
        </div>
        <p className="App-intro" onClick={this.myClickFunc}>
          To get started, edit <code>src/App.js</code> and save to reload.
        </p>
      </div>
    );
  }
}

You can now make assertions about the state of the component, i.e.

describe('my sweet test', () => {
 it('clicks it', () => {
    const app = shallow(<App />)
    const p = app.find('.App-intro')
    p.simulate('click')
    expect(app.state('aProperty')).toEqual('second');
 })
})

How to see docker image contents

EXPLORING DOCKER IMAGE!

  1. Figure out what kind of shell is in there bash or sh...

Inspect the image first: docker inspect name-of-container-or-image

Look for entrypoint or cmd in the JSON return.

  1. Then do: docker run --rm -it --entrypoint=/bin/bash name-of-image

once inside do: ls -lsa or any other shell command like: cd ..

The -it stands for interactive... and TTY. The --rm stands for remove container after run.

If there are no common tools like ls or bash present and you have access to the Dockerfile simple add the common tool as a layer.
example (alpine Linux):

RUN apk add --no-cache bash

And when you don't have access to the Dockerfile then just copy/extract the files from a newly created container and look through them:

docker create <image>  # returns container ID the container is never started.
docker cp <container ID>:<source_path> <destination_path>
docker rm <container ID>
cd <destination_path> && ls -lsah

No signing certificate "iOS Distribution" found

Tried the above solutions with no luck ... restarted my mac solved the issue...

How to add external JS scripts to VueJS Components

You can use the vue-head package to add scripts, and other tags to the head of your vue component.

Its as simple as:

var myComponent = Vue.extend({
  data: function () {
    return {
      ...
    }
  },
  head: {
    title: {
      inner: 'It will be a pleasure'
    },
    // Meta tags
    meta: [
      { name: 'application-name', content: 'Name of my application' },
      { name: 'description', content: 'A description of the page', id: 'desc' }, // id to replace intead of create element
      // ...
      // Twitter
      { name: 'twitter:title', content: 'Content Title' },
      // with shorthand
      { n: 'twitter:description', c: 'Content description less than 200 characters'},
      // ...
      // Google+ / Schema.org
      { itemprop: 'name', content: 'Content Title' },
      { itemprop: 'description', content: 'Content Title' },
      // ...
      // Facebook / Open Graph
      { property: 'fb:app_id', content: '123456789' },
      { property: 'og:title', content: 'Content Title' },
      // with shorthand
      { p: 'og:image', c: 'https://example.com/image.jpg' },
      // ...
    ],
    // link tags
    link: [
      { rel: 'canonical', href: 'http://example.com/#!/contact/', id: 'canonical' },
      { rel: 'author', href: 'author', undo: false }, // undo property - not to remove the element
      { rel: 'icon', href: require('./path/to/icon-16.png'), sizes: '16x16', type: 'image/png' }, 
      // with shorthand
      { r: 'icon', h: 'path/to/icon-32.png', sz: '32x32', t: 'image/png' },
      // ...
    ],
    script: [
      { type: 'text/javascript', src: 'cdn/to/script.js', async: true, body: true}, // Insert in body
      // with shorthand
      { t: 'application/ld+json', i: '{ "@context": "http://schema.org" }' },
      // ...
    ],
    style: [
      { type: 'text/css', inner: 'body { background-color: #000; color: #fff}', undo: false },
      // ...
    ]
  }
})

Check out this link for more examples.

Maintaining href "open in new tab" with an onClick handler in React

React + TypeScript inline util method:

const navigateToExternalUrl = (url: string, shouldOpenNewTab: boolean = true) =>
shouldOpenNewTab ? window.open(url, "_blank") : window.location.href = url;

Angular 4 img src is not found

Copy your images into the assets folder. Angular can only access static files like images and config files from assets folder.

Try like this: <img src="assets/img/myimage.png">

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

Just npm install --save-dev cross-env in the root directory of your project.

Using app.config in .Net Core

  1. You can use Microsoft.Extensions.Configuration API with any .NET Core app, not only with ASP.NET Core app. Look into sample provided in the link, that shows how to read configs in the console app.

  2. In most cases, the JSON source (read as .json file) is the most suitable config source.

    Note: don't be confused when someone says that config file should be appsettings.json. You can use any file name, that is suitable for you and file location may be different - there are no specific rules.

    But, as the real world is complicated, there are a lot of different configuration providers:

    • File formats (INI, JSON, and XML)
    • Command-line arguments
    • Environment variables

    and so on. You even could use/write a custom provider.

  3. Actually, app.config configuration file was an XML file. So you can read settings from it using XML configuration provider (source on github, nuget link). But keep in mind, it will be used only as a configuration source - any logic how your app behaves should be implemented by you. Configuration Provider will not change 'settings' and set policies for your apps, but only read data from the file.

Uncaught Error: Unexpected module 'FormsModule' declared by the module 'AppModule'. Please add a @Pipe/@Directive/@Component annotation

Remove the FormsModule from Declaration:[] and Add the FormsModule in imports:[]

@NgModule({
  declarations: [
    AppComponent
  ],
  imports: [
    BrowserModule,
    FormsModule
  ],
  providers: [],
  bootstrap: [AppComponent]
})

How to use router.navigateByUrl and router.navigate in Angular

From my understanding, router.navigate is used to navigate relatively to current path. For eg : If our current path is abc.com/user, we want to navigate to the url : abc.com/user/10 for this scenario we can use router.navigate .


router.navigateByUrl() is used for absolute path navigation.

ie,

If we need to navigate to entirely different route in that case we can use router.navigateByUrl

For example if we need to navigate from abc.com/user to abc.com/assets, in this case we can use router.navigateByUrl()


Syntax :

router.navigateByUrl(' ---- String ----');

router.navigate([], {relativeTo: route})

Why does "npm install" rewrite package-lock.json?

There is an open issue for this on their github page: https://github.com/npm/npm/issues/18712

This issue is most severe when developers are using different operating systems.

Vue JS mounted()

You can also move mounted out of the Vue instance and make it a function in the top-level scope. This is also a useful trick for server side rendering in Vue.

function init() {
  // Use `this` normally
}

new Vue({
  methods:{
    init
  },
  mounted(){
    init.call(this)
  }
})

How do I test axios in Jest?

I used axios-mock-adapter. In this case the service is described in ./chatbot. In the mock adapter you specify what to return when the API endpoint is consumed.

import axios from 'axios';
import MockAdapter from 'axios-mock-adapter';
import chatbot from './chatbot';

describe('Chatbot', () => {
    it('returns data when sendMessage is called', done => {
        var mock = new MockAdapter(axios);
        const data = { response: true };
        mock.onGet('https://us-central1-hutoma-backend.cloudfunctions.net/chat').reply(200, data);

        chatbot.sendMessage(0, 'any').then(response => {
            expect(response).toEqual(data);
            done();
        });
    });
});

You can see it the whole example here:

Service: https://github.com/lnolazco/hutoma-test/blob/master/src/services/chatbot.js

Test: https://github.com/lnolazco/hutoma-test/blob/master/src/services/chatbot.test.js

How do I fix "Expected to return a value at the end of arrow function" warning?

The problem seems to be that you are not returning something in the event that your first if-case is false.

The error you are getting states that your arrow function (comment) => { doesn't have a return statement. While it does for when your if-case is true, it does not return anything for when it's false.

return this.props.comments.map((comment) => {
  if (comment.hasComments === true) {
    return (
      <div key={comment.id}>
        <CommentItem className="MainComment" />
        {this.props.comments.map(commentReply => {
          if (commentReply.replyTo === comment.id) { 
            return (
              <CommentItem className="SubComment"/>
            )
          }
        })
        }
      </div>
    )
  } else {
     //return something here.
  }
});

edit you should take a look at Kris' answer for how to better implement what you are trying to do.

Check if a string is not NULL or EMPTY

If the variable is a parameter then you could use advanced function parameter binding like below to validate not null or empty:

[CmdletBinding()]
Param (
    [parameter(mandatory=$true)]
    [ValidateNotNullOrEmpty()]
    [string]$Version
)

Bootstrap 4 dropdown with search

As of 10. July 2017, the issue of Bootstrap 4 support with bootstrap-select is still open. In the open issue, there are some ad-hoc solutions which you could try with your project.

Or you could use a library like Select2 and add a theme to match Bootstrap 4. Here is an example: Select 2 with Bootstrap 4 (disclaimer: I'm not the author of this blog post and I haven't verified if this still works with the all versions of Bootstrap 4).

Vue js error: Component template should contain exactly one root element

instead of using this

Vue.component('tabs', {
    template: `
        <div class="tabs">
          <ul>
            <li class="is-active"><a>Pictures</a></li>
            <li><a>Music</a></li>
            <li><a>Videos</a></li>
            <li><a>Documents</a></li>
          </ul>
        </div>

        <div class="tabs-content">
          <slot></slot>
        </div>
    `,
});

you should use


Vue.component('tabs', {
    template: `
      <div>
        <div class="tabs">
          <ul>
            <li class="is-active"><a>Pictures</a></li>
            <li><a>Music</a></li>
            <li><a>Videos</a></li>
            <li><a>Documents</a></li>
          </ul>
        </div>

        <div class="tabs-content">
          <slot></slot>
        </div>
      </div>
    `,
});

How can I dismiss the on screen keyboard?

Looks like different approaches for different version. I am using Flutter v1.17.1 and the below works for me.

onTap: () {
    FocusScopeNode currentFocus = FocusScope.of(context);
    if (!currentFocus.hasPrimaryFocus && currentFocus.focusedChild != null) {
       currentFocus.focusedChild.unfocus();
    }
}

No restricted globals

This is a simple and maybe not the best solution, but it works.

On the line above the line you get your error, paste this:

// eslint-disable-next-line no-restricted-globals

Generating a PDF file from React Components

I used jsPDF and html-to-image.

You can check out the code on the below git repo.

Link

If you like, you can drop a star there??

Bootstrap 4, how to make a col have a height of 100%?

I came across this problem because my cols exceeded the row grid length (> 12)

A solution using 100% Bootstrap 4:

Since the rows in Bootstrap are already display: flex

You just need to add flex-fill to the Col, and h-100 to the container and any children.

Pen here: https://codepen.io/joshkopecek/pen/Exjdgjo

<div class="container-fluid h-100">
  <div class="row justify-content-center h-100">

    <div class="col-4 hidden-md-down flex-fill" id="yellow">
      XXXX
    </div>

    <div id="blue" class="col-10 col-sm-10 col-md-10 col-lg-8 col-xl-8 h-100">
      Form Goes Here
    </div>

    <div id="green" class="col-10 col-sm-10 col-md-10 col-lg-8 col-xl-8 h-100">
      Another form
    </div>
  </div>
</div>

flutter remove back button on appbar

I believe the solutions are the following

You actually either:

  • Don't want to display that ugly back button ( :] ), and thus go for : AppBar(...,automaticallyImplyLeading: false,...);

  • Don't want the user to go back - replacing current view - and thus go for: Navigator.pushReplacementNamed(## your routename here ##);

  • Don't want the user to go back - replacing a certain view back in the stack - and thus use: Navigator.pushNamedAndRemoveUntil(## your routename here ##, f(Route<dynamic>)?bool); where f is a function returning truewhen meeting the last view you want to keep in the stack (right before the new one);

  • Don't want the user to go back - EVER - emptying completely the navigator stack with: Navigator.pushNamedAndRemoveUntil(context, ## your routename here ##, (_) => false);

Cheers

How to get am pm from the date time string using moment js

You are using the wrong format tokens when parsing your input. You should use ddd for an abbreviation of the name of day of the week, DD for day of the month, MMM for an abbreviation of the month's name, YYYY for the year, hh for the 1-12 hour, mm for minutes and A for AM/PM. See moment(String, String) docs.

Here is a working live sample:

_x000D_
_x000D_
console.log( moment('Mon 03-Jul-2017, 11:00 AM', 'ddd DD-MMM-YYYY, hh:mm A').format('hh:mm A') );_x000D_
console.log( moment('Mon 03-Jul-2017, 11:00 PM', 'ddd DD-MMM-YYYY, hh:mm A').format('hh:mm A') );
_x000D_
<script src="https://cdnjs.cloudflare.com/ajax/libs/moment.js/2.18.1/moment.min.js"></script>
_x000D_
_x000D_
_x000D_

If condition inside of map() React

This one I found simple solutions:

row = myArray.map((cell, i) => {

    if (i == myArray.length - 1) {
      return <div> Test Data 1</div>;
    }
    return <div> Test Data 2</div>;
  });

The term 'ng' is not recognized as the name of a cmdlet

If you do not have access to Environmental variable (e.g. office machines).

You can try to run command like this:

npm run <your angular command>

it works as well, just need to add npm run before ng command

Example -> npm run ng g c shop/cart

enter image description here

How to start Spyder IDE on Windows

Try these commands in order

pip3 install spyder
spyder3

iOS 11, 12, and 13 installed certificates not trusted automatically (self signed)

While writing this question, I discovered the answer. Installing a CA from Safari no longer automatically trusts it. I had to manually trust it from the Certificate Trust Settings panel (also mentioned in this question).

enter image description here

I debated canceling the question, but I thought it might be helpful to have some of the relevant code and log details someone might be looking for. Also, I never encountered the issue until iOS 11. I even went back and reconfirmed that it automatically works up through iOS 10.

I've never needed to touch that settings panel before, because any installed certificates were automatically trusted. Maybe it will change by the time iOS 11 ships, but I doubt it. Hopefully this helps save someone the time I wasted.

If anyone knows why this behaves differently for some people on different versions of iOS, I'd love to know in comments.

Update 1: Checking out the first iOS 12 beta, it looks like things remain the same. This question/answer/comments are still relevant on iOS 12.

Update 2: Same solution seems to be needed on iOS 13 beta builds as well.

Pip error: Microsoft Visual C++ 14.0 is required

Try doing this:

py -m pip install pipwin
py -m pipwin install PyAudio

How to make a movie out of images in python

Thanks , but i found an alternative solution using ffmpeg:

def save():
    os.system("ffmpeg -r 1 -i img%01d.png -vcodec mpeg4 -y movie.mp4")

But thank you for your help :)

How to convert Observable<any> to array[]

You will need to subscribe to your observables:

this.CountryService.GetCountries()
    .subscribe(countries => {
        this.myGridOptions.rowData = countries as CountryData[]
    })

And, in your html, wherever needed, you can pass the async pipe to it.

what is .subscribe in angular?

In Angular (currently on Angular-6) .subscribe() is a method on the Observable type. The Observable type is a utility that asynchronously or synchronously streams data to a variety of components or services that have subscribed to the observable.

The observable is an implementation/abstraction over the promise chain and will be a part of ES7 as a proposed and very supported feature. In Angular it is used internally due to rxjs being a development dependency.

An observable itself can be thought of as a stream of data coming from a source, in Angular this source is an API-endpoint, a service, a database or another observable. But the power it has is that it's not expecting a single response. It can have one or many values that are returned.

Link to rxjs for observable/subscribe docs here: https://rxjs-dev.firebaseapp.com/api/index/class/Observable#subscribe-

Subscribe takes 3 methods as parameters each are functions:

  • next: For each item being emitted by the observable perform this function
  • error: If somewhere in the stream an error is found, do this method
  • complete: Once all items are complete from the stream, do this method

Within each of these, there is the potentional to pipe (or chain) other utilities called operators onto the results to change the form or perform some layered logic.

In the simple example above:

.subscribe(hero => this.hero = hero); basically says on this observable take the hero being emitted and set it to this.hero.

Adding this answer to give more context to Observables based off the documentation and my understanding.

Python TypeError must be str not int

Python comes with numerous ways of formatting strings:

New style .format(), which supports a rich formatting mini-language:

>>> temperature = 10
>>> print("the furnace is now {} degrees!".format(temperature))
the furnace is now 10 degrees!

Old style % format specifier:

>>> print("the furnace is now %d degrees!" % temperature)
the furnace is now 10 degrees!

In Py 3.6 using the new f"" format strings:

>>> print(f"the furnace is now {temperature} degrees!")
the furnace is now 10 degrees!

Or using print()s default separator:

>>> print("the furnace is now", temperature, "degrees!")
the furnace is now 10 degrees!

And least effectively, construct a new string by casting it to a str() and concatenating:

>>> print("the furnace is now " + str(temperature) + " degrees!")
the furnace is now 10 degrees!

Or join()ing it:

>>> print(' '.join(["the furnace is now", str(temperature), "degrees!"]))
the furnace is now 10 degrees!