Programs & Examples On #Import module

Powershell: A positional parameter cannot be found that accepts argument "xxx"

I had to use

powershell.AddCommand("Get-ADPermission");
powershell.AddParameter("Identity", "complete id path with OU in it");

to get past this error

sys.path different in Jupyter and Python - how to import own modules in Jupyter?

Suppose your project has the following structure and you want to do imports in the notebook.ipynb:

/app
  /mypackage
    mymodule.py
  /notebooks
    notebook.ipynb

If you are running Jupyter inside a docker container without any virtualenv it might be useful to create Jupyter (ipython) config in your project folder:

/app
  /profile_default
    ipython_config.py

Content of ipython_config.py:

c.InteractiveShellApp.exec_lines = [
    'import sys; sys.path.append("/app")'
]

Open the notebook and check it out:

print(sys.path)

['', '/usr/local/lib/python36.zip', '/usr/local/lib/python3.6', '/usr/local/lib/python3.6/lib-dynload', '/usr/local/lib/python3.6/site-packages', '/usr/local/lib/python3.6/site-packages/IPython/extensions', '/root/.ipython', '/app']

Now you can do imports in your notebook without any sys.path appending in the cells:

from mypackage.mymodule import myfunc

How do I check if a PowerShell module is installed?

Coming from Linux background. I would prefer using something similar to grep, therefore I use Select-String. So even if someone is not sure of the complete module name. They can provide the initials and determine whether the module exists or not.

Get-Module -ListAvailable -All | Select-String Module_Name(can be a part of the module name)

PyCharm error: 'No Module' when trying to import own module (python script)

I was getting the error with "Add source roots to PYTHONPATH" as well. My problem was that I had two folders with the same name, like project/subproject1/thing/src and project/subproject2/thing/src and I had both of them marked as source root. When I renamed one of the "thing" folders to "thing1" (any unique name), it worked.

Maybe if PyCharm automatically adds selected source roots, it doesn't use the full path and hence mixes up folders with the same name.

How do I assign a null value to a variable in PowerShell?

Use $dec = $null

From the documentation:

$null is an automatic variable that contains a NULL or empty value. You can use this variable to represent an absent or undefined value in commands and scripts.

PowerShell treats $null as an object with a value, that is, as an explicit placeholder, so you can use $null to represent an empty value in a series of values.

Powershell: count members of a AD group

$users = Get-ADGroupMember -Identity 'Client Services' -Recursive ; $users.count

The above one-liner gives a clean count of recursive members found. Simple, easy, and one line.

java.lang.ClassNotFoundException: Didn't find class on path: dexpathlist

delete 'android/app/.settings' folder

or

delete 'android/.settings' folder

or

delete 'android/.build' folder

or

delete 'android/.idea' folder

and

yarn react-native run android

Import-Module : The specified module 'activedirectory' was not loaded because no valid module file was found in any module directory

You can install the Active Directory snap-in with Powershell on Windows Server 2012 using the following command:

Install-windowsfeature -name AD-Domain-Services –IncludeManagementTools

This helped me when I had problems with the Features screen due to AppFabric and Windows Update errors.

Powershell import-module doesn't find modules

1.This will search XMLHelpers/XMLHelpers.psm1 in current folder

Import-Module (Resolve-Path('XMLHelpers'))

2.This will search XMLHelpers.psm1 in current folder

Import-Module (Resolve-Path('XMLHelpers.psm1'))

Exchange Powershell - How to invoke Exchange 2010 module from inside script?

You can do this:

add-pssnapin Microsoft.Exchange.Management.PowerShell.E2010

and most of it will work (although MS support will tell you that doing this is not supported because it bypasses RBAC).

I've seen issues with some cmdlets (specifically enable/disable UMmailbox) not working with just the snapin loaded.

In Exchange 2010, they basically don't support using Powershell outside of the the implicit remoting environment of an actual EMS shell.

React - Display loading screen while DOM is rendering?

If anyone looking for a drop-in, zero-config and zero-dependencies library for the above use-case, try pace.js (http://github.hubspot.com/pace/docs/welcome/).

It automatically hooks to events (ajax, readyState, history pushstate, js event loop etc) and show a customizable loader.

Worked well with our react/relay projects (handles navigation changes using react-router, relay requests) (Not affliated; had used pace.js for our projects and it worked great)

Twitter-Bootstrap-2 logo image on top of navbar

i use this code for navbar on bootstrap 3.2.0, the image should be at most 50px high, or else it will bleed the standard bs navbar.

Notice that i purposely do not use the class='navbar-brand' as that introduces padding on the image

<div class="navbar navbar-default navbar-fixed-top" role="navigation">
    <div class="container">
    <!-- Brand and toggle get grouped for better mobile display -->
    <div class="navbar-header">
      <button type="button" class="navbar-toggle" data-toggle="collapse" data-target=".navbar-ex1-collapse">
        <span class="sr-only">Toggle navigation</span>
        <span class="icon-bar"></span>
        <span class="icon-bar"></span>
        <span class="icon-bar"></span>
      </button>
      <a class="" href="/"><img src='img/anyWidthx50.png'/></a>
    </div>

    <!-- Collect the nav links, forms, and other content for toggling -->
    <div class="collapse navbar-collapse navbar-ex1-collapse">
       <ul class="nav navbar-nav">
        <li class="active"><a href="#">Active Link</a></li>
        <li><a href="#">More Links</a></li>
      </ul>
    </div><!-- /.navbar-collapse -->
  </div>
</div>

api-ms-win-crt-runtime-l1-1-0.dll is missing when opening Microsoft Office file

if anybody unable to update windows online, I suggest you go to http://download.wsusoffline.net/ and download Most recent version.

Then install update generator -> select your operating system. and hit START, just wait few minutes let him download updates and complete all it's process. hope this help.

Image of Offline update generator

Insert into C# with SQLCommand

using (SqlConnection connection = new SqlConnection(connectionString)) 
{
    connection.Open(); 
    using (SqlCommand command = connection.CreateCommand()) 
    { 
        command.CommandText = "INSERT INTO klant(klant_id,naam,voornaam) VALUES(@param1,@param2,@param3)";  

        command.Parameters.AddWithValue("@param1", klantId));  
        command.Parameters.AddWithValue("@param2", klantNaam));  
        command.Parameters.AddWithValue("@param3", klantVoornaam));  

        command.ExecuteNonQuery(); 
    } 
}

Hash Table/Associative Array in VBA

Here we go... just copy the code to a module, it's ready to use

Private Type hashtable
    key As Variant
    value As Variant
End Type

Private GetErrMsg As String

Private Function CreateHashTable(htable() As hashtable) As Boolean
    GetErrMsg = ""
    On Error GoTo CreateErr
        ReDim htable(0)
        CreateHashTable = True
    Exit Function

CreateErr:
    CreateHashTable = False
    GetErrMsg = Err.Description
End Function

Private Function AddValue(htable() As hashtable, key As Variant, value As Variant) As Long
    GetErrMsg = ""
    On Error GoTo AddErr
        Dim idx As Long
        idx = UBound(htable) + 1

        Dim htVal As hashtable
        htVal.key = key
        htVal.value = value

        Dim i As Long
        For i = 1 To UBound(htable)
            If htable(i).key = key Then Err.Raise 9999, , "Key [" & CStr(key) & "] is not unique"
        Next i

        ReDim Preserve htable(idx)

        htable(idx) = htVal
        AddValue = idx
    Exit Function

AddErr:
    AddValue = 0
    GetErrMsg = Err.Description
End Function

Private Function RemoveValue(htable() As hashtable, key As Variant) As Boolean
    GetErrMsg = ""
    On Error GoTo RemoveErr

        Dim i As Long, idx As Long
        Dim htTemp() As hashtable
        idx = 0

        For i = 1 To UBound(htable)
            If htable(i).key <> key And IsEmpty(htable(i).key) = False Then
                ReDim Preserve htTemp(idx)
                AddValue htTemp, htable(i).key, htable(i).value
                idx = idx + 1
            End If
        Next i

        If UBound(htable) = UBound(htTemp) Then Err.Raise 9998, , "Key [" & CStr(key) & "] not found"

        htable = htTemp
        RemoveValue = True
    Exit Function

RemoveErr:
    RemoveValue = False
    GetErrMsg = Err.Description
End Function

Private Function GetValue(htable() As hashtable, key As Variant) As Variant
    GetErrMsg = ""
    On Error GoTo GetValueErr
        Dim found As Boolean
        found = False

        For i = 1 To UBound(htable)
            If htable(i).key = key And IsEmpty(htable(i).key) = False Then
                GetValue = htable(i).value
                Exit Function
            End If
        Next i
        Err.Raise 9997, , "Key [" & CStr(key) & "] not found"

    Exit Function

GetValueErr:
    GetValue = ""
    GetErrMsg = Err.Description
End Function

Private Function GetValueCount(htable() As hashtable) As Long
    GetErrMsg = ""
    On Error GoTo GetValueCountErr
        GetValueCount = UBound(htable)
    Exit Function

GetValueCountErr:
    GetValueCount = 0
    GetErrMsg = Err.Description
End Function

To use in your VB(A) App:

Public Sub Test()
    Dim hashtbl() As hashtable
    Debug.Print "Create Hashtable: " & CreateHashTable(hashtbl)
    Debug.Print ""
    Debug.Print "ID Test   Add V1: " & AddValue(hashtbl, "Hallo_0", "Testwert 0")
    Debug.Print "ID Test   Add V2: " & AddValue(hashtbl, "Hallo_0", "Testwert 0")
    Debug.Print "ID Test 1 Add V1: " & AddValue(hashtbl, "Hallo.1", "Testwert 1")
    Debug.Print "ID Test 2 Add V1: " & AddValue(hashtbl, "Hallo-2", "Testwert 2")
    Debug.Print "ID Test 3 Add V1: " & AddValue(hashtbl, "Hallo 3", "Testwert 3")
    Debug.Print ""
    Debug.Print "Test 1 Removed V1: " & RemoveValue(hashtbl, "Hallo_1")
    Debug.Print "Test 1 Removed V2: " & RemoveValue(hashtbl, "Hallo_1")
    Debug.Print "Test 2 Removed V1: " & RemoveValue(hashtbl, "Hallo-2")
    Debug.Print ""
    Debug.Print "Value Test 3: " & CStr(GetValue(hashtbl, "Hallo 3"))
    Debug.Print "Value Test 1: " & CStr(GetValue(hashtbl, "Hallo_1"))
    Debug.Print ""
    Debug.Print "Hashtable Content:"

    For i = 1 To UBound(hashtbl)
        Debug.Print CStr(i) & ": " & CStr(hashtbl(i).key) & " - " & CStr(hashtbl(i).value)
    Next i

    Debug.Print ""
    Debug.Print "Count: " & CStr(GetValueCount(hashtbl))
End Sub

Excel CSV. file with more than 1,048,576 rows of data

I would suggest to load the .CSV file in MS-Access.

With MS-Excel you can then create a data connection to this source (without actual loading the records in a worksheet) and create a connected pivot table. You then can have virtually unlimited number of lines in your table (depending on processor and memory: I have now 15 mln lines with 3 Gb Memory).

Additional advantage is that you can now create an aggregate view in MS-Access. In this way you can create overviews from hundreds of millions of lines and then view them in MS-Excel (beware of the 2Gb limitation of NTFS files in 32 bits OS).

Unsetting array values in a foreach loop

You can use the index of the array element to remove it from the array, the next time you use the $list variable, you will see that the array is changed.

Try something like this

foreach($list as $itemIndex => &$item) {

   if($item['status'] === false) {
      unset($list[$itemIndex]);
   }

}

How to automatically start a service when running a docker container?

Simple! Add at the end of dockerfile:

ENTRYPOINT service mysql start && /bin/bash

How to list all the roles existing in Oracle database?

Got the answer :

SELECT * FROM DBA_ROLES;

receiver type *** for instance message is a forward declaration

You are using

States states;

where as you should use

States *states;

Your init method should be like this

-(id)init {
  if( (self = [super init]) ) {
      pickedGlasses = 0;
  }
  return self;
}

Now finally when you are going to create an object for States class you should do it like this.

State *states = [[States alloc] init];

I am not saying this is the best way of doing this. But it may help you understand the very basic use of initializing objects.

Apply function to pandas groupby

Try:

g = pd.DataFrame(['A','B','A','C','D','D','E'])

# Group by the contents of column 0 
gg = g.groupby(0)  

# Create a DataFrame with the counts of each letter
histo = gg.apply(lambda x: x.count())

# Add a new column that is the count / total number of elements    
histo[1] = histo.astype(np.float)/len(g) 

print histo

Output:

   0         1
0             
A  2  0.285714
B  1  0.142857
C  1  0.142857
D  2  0.285714
E  1  0.142857

Environment.GetFolderPath(...CommonApplicationData) is still returning "C:\Documents and Settings\" on Vista

Output on Ubuntu 9.10 -> Ubuntu 12.04 with mono 2.10.8.1:

SpecialFolder.ApplicationData: /home/$USER/.config
SpecialFolder.CommonApplicationData: /usr/share
SpecialFolder.ProgramFiles: 
SpecialFolder.DesktopDirectory: /home/$USER/Desktop
SpecialFolder.LocalApplicationData: /home/$USER/.local/share
SpecialFolder.MyDocuments: /home/$USER
SpecialFolder.System: 

SpecialFolder.Personal: /home/$USER

Output on Ubuntu 16.04 with mono 4.2.1

SpecialFolder.ApplicationData: /home/$USER/.config
SpecialFolder.CommonApplicationData: /usr/share
SpecialFolder.ProgramFiles:
SpecialFolder.DesktopDirectory: /home/$USER/Desktop
SpecialFolder.LocalApplicationData: /home/$USER/.local/share
SpecialFolder.MyDocuments: /home/$USER
SpecialFolder.Desktop: /home/$USER/Desktop
SpecialFolder.Personal: /home/$USER

SpecialFolder.System: 
SpecialFolder.Programs: 
SpecialFolder.Favorites: 
SpecialFolder.Startup: 
SpecialFolder.Recent: 
SpecialFolder.SendTo: 
SpecialFolder.StartMenu: 
SpecialFolder.MyMusic: /home/$USER/Music
SpecialFolder.MyVideos: /home/$USER/Videos
SpecialFolder.MyComputer: 
SpecialFolder.NetworkShortcuts: 
SpecialFolder.Fonts: /home/$USER/.fonts
SpecialFolder.Templates: /home/$USER/Templates
SpecialFolder.CommonStartMenu: 
SpecialFolder.CommonPrograms: 
SpecialFolder.CommonStartup: 
SpecialFolder.CommonDesktopDirectory: 
SpecialFolder.PrinterShortcuts: 
SpecialFolder.InternetCache: 
SpecialFolder.Cookies: 
SpecialFolder.History: 
SpecialFolder.Windows: 
SpecialFolder.MyPictures: /home/$USER/Pictures
SpecialFolder.UserProfile: /home/$USER
SpecialFolder.SystemX86: 
SpecialFolder.ProgramFilesX86: 
SpecialFolder.CommonProgramFiles: 
SpecialFolder.CommonProgramFilesX86: 
SpecialFolder.CommonTemplates: /usr/share/templates
SpecialFolder.CommonDocuments: 
SpecialFolder.CommonAdminTools: 
SpecialFolder.AdminTools: 
SpecialFolder.CommonMusic: 
SpecialFolder.CommonPictures: 
SpecialFolder.CommonVideos: 
SpecialFolder.Resources: 
SpecialFolder.LocalizedResources: 
SpecialFolder.CommonOemLinks: 
SpecialFolder.CDBurning: 

where $USER is the current user

Output on Ubuntu 16.04 using dotnet core (3.0.100)

ApplicationData: /home/$USER/.config
CommonApplicationData: /usr/share
ProgramFiles: 
DesktopDirectory: /home/$USER/Desktop
LocalApplicationData: /home/$USER/.local/share
MyDocuments: /home/$USER
System: 
Personal: /home/$USER

Output on Android 6 using Xamarin 7.2

Environment.SpecialFolder.ApplicationData: /data/user/0/$APPNAME/files/.config
Environment.SpecialFolder.CommonApplicationData: /usr/share
Environment.SpecialFolder.ProgramFiles: 
Environment.SpecialFolder.DesktopDirectory: /data/user/0/$APPNAME/files/Desktop
Environment.SpecialFolder.LocalApplicationData: /data/user/0/$APPNAME/files/.local/share
Environment.SpecialFolder.MyDocuments: /data/user/0/$APPNAME/files
Environment.SpecialFolder.Desktop: /data/user/0/$APPNAME/files/Desktop
Environment.SpecialFolder.Personal: /data/user/0/$APPNAME/files

Environment.SpecialFolder.Startup: 
Environment.SpecialFolder.Recent: 
Environment.SpecialFolder.SendTo: 
Environment.SpecialFolder.StartMenu: 
Environment.SpecialFolder.MyMusic: /data/user/0/$APPNAME/files/Music
Environment.SpecialFolder.MyVideos: /data/user/0/$APPNAME/files/Videos
Environment.SpecialFolder.MyComputer: 
Environment.SpecialFolder.NetworkShortcuts: 
Environment.SpecialFolder.Fonts: /data/user/0/$APPNAME/files/.fonts
Environment.SpecialFolder.Templates: /data/user/0/$APPNAME/files/Templates
Environment.SpecialFolder.CommonStartMenu: 
Environment.SpecialFolder.CommonPrograms: 
Environment.SpecialFolder.CommonStartup: 
Environment.SpecialFolder.CommonDesktopDirectory: 
Environment.SpecialFolder.PrinterShortcuts: 
Environment.SpecialFolder.InternetCache: 
Environment.SpecialFolder.Cookies: 
Environment.SpecialFolder.History: 
Environment.SpecialFolder.Windows: 
Environment.SpecialFolder.MyPictures: /data/user/0/$APPNAME/files/Pictures
Environment.SpecialFolder.UserProfile: /data/user/0/$APPNAME/files
Environment.SpecialFolder.SystemX86: 
Environment.SpecialFolder.ProgramFilesX86: 
Environment.SpecialFolder.CommonProgramFiles: 
Environment.SpecialFolder.CommonProgramFilesX86: 
Environment.SpecialFolder.CommonTemplates: /usr/share/templates
Environment.SpecialFolder.CommonDocuments: 
Environment.SpecialFolder.CommonAdminTools: 
Environment.SpecialFolder.AdminTools: 
Environment.SpecialFolder.CommonMusic: 
Environment.SpecialFolder.CommonPictures: 
Environment.SpecialFolder.CommonVideos: 
Environment.SpecialFolder.Resources: 
Environment.SpecialFolder.LocalizedResources: 
Environment.SpecialFolder.CommonOemLinks: 
Environment.SpecialFolder.CDBurning: 

Where $APPNAME is the name of your Xamarin application (eg. MyApp.Droid)

Output on iOS Simulator 10.3 using Xamarin 7.2

ApplicationData: /Users/$USER/Library/Developer/CoreSimulator/Devices/$DEVICEGUID/data/Containers/Data/Application/$APPLICATIONGUID/Documents/.config
CommonApplicationData: /usr/share
ProgramFiles: /Applications
DesktopDirectory: /Users/$USER/Library/Developer/CoreSimulator/Devices/$DEVICEGUID/data/Containers/Data/Application/$APPLICATIONGUID/Documents/Desktop
LocalApplicationData: /Users/$USER/Library/Developer/CoreSimulator/Devices/$DEVICEGUID/data/Containers/Data/Application/$APPLICATIONGUID/Documents
MyDocuments: /Users/$USER/Library/Developer/CoreSimulator/Devices/$DEVICEGUID/data/Containers/Data/Application/$APPLICATIONGUID/Documents
Desktop: /Users/$USER/Library/Developer/CoreSimulator/Devices/$DEVICEGUID/data/Containers/Data/Application/$APPLICATIONGUID/Documents/Desktop
MyDocuments: /Users/$USER/Library/Developer/CoreSimulator/Devices/$DEVICEGUID/data/Containers/Data/Application/$APPLICATIONGUID/Documents
Startup: 
Recent: 
SendTo: 
StartMenu: 
MyMusic: /Users/$USER/Library/Developer/CoreSimulator/Devices/$DEVICEGUID/data/Containers/Data/Application/$APPLICATIONGUID/Documents/Music
MyVideos: /Users/$USER/Library/Developer/CoreSimulator/Devices/$DEVICEGUID/data/Containers/Data/Application/$APPLICATIONGUID/Documents/Videos
MyComputer: 
NetworkShortcuts: 
Fonts: /Users/$USER/Library/Developer/CoreSimulator/Devices/$DEVICEGUID/data/Containers/Data/Application/$APPLICATIONGUID/Documents/.fonts
Templates: /Users/$USER/Library/Developer/CoreSimulator/Devices/$DEVICEGUID/data/Containers/Data/Application/$APPLICATIONGUID/Documents/Templates
CommonStartMenu: 
CommonPrograms: 
CommonStartup: 
CommonDesktopDirectory: 
PrinterShortcuts: 
InternetCache: /Users/$USER/Library/Developer/CoreSimulator/Devices/$DEVICEGUID/data/Containers/Data/Application/$APPLICATIONGUID/Library/Caches
Cookies: 
History: 
Windows: 
MyPictures: /Users/$USER/Library/Developer/CoreSimulator/Devices/$DEVICEGUID/data/Containers/Data/Application/$APPLICATIONGUID/Documents/Pictures
UserProfile: /Users/$USER/Library/Developer/CoreSimulator/Devices/$DEVICEGUID/data/Containers/Data/Application/$APPLICATIONGUID
SystemX86: 
ProgramFilesX86: 
CommonProgramFiles: 
CommonProgramFilesX86: 
CommonTemplates: /usr/share/templates
CommonDocuments: 
CommonAdminTools: 
AdminTools: 
CommonMusic: 
CommonPictures: 
CommonVideos: 
Resources: /Users/$USER/Library/Developer/CoreSimulator/Devices/$DEVICEGUID/data/Containers/Data/Application/$APPLICATIONGUID/Library
LocalizedResources: 
CommonOemLinks: 
CDBurning: 

Where $DEVICEGUID is the simulator GUID (depending on the selected simulator)

Output on ipad 10.3 using Xamarin 7.2

SpecialFolder.MyDocuments: /var/mobile/Containers/Data/Application/$APPLICATIONGUID/Documents

Output on ipad 13.3 using Xamarin 16.4

SpecialFolder.MyDocuments: /var/mobile/Containers/Data/Application/$APPLICATIONGUID/Documents
SpecialFolder.UserProfile: /private/var/mobile/Containers/Data/Application/$APPLICATIONGUID/Documents

Output on windows 10 using .net core 3.1

SpecialFolder.MyDocuments: C:\Users\$USER\Documents

Output on Ubuntu 18.04 using .net core 3.1

SpecialFolder.MyDocuments: /home/$USER

Output on MacOS Catalina using .net core 3.1

SpecialFolder.MyDocuments: /Users/$USER

Make div scrollable

Place this into your DIV style

overflow:scroll;

Test if a string contains any of the strings from an array

If you use Java 8 or above, you can rely on the Stream API to do such thing:

public static boolean containsItemFromArray(String inputString, String[] items) {
    // Convert the array of String items as a Stream
    // For each element of the Stream call inputString.contains(element)
    // If you have any match returns true, false otherwise
    return Arrays.stream(items).anyMatch(inputString::contains);
}

Assuming that you have a big array of big String to test you could also launch the search in parallel by calling parallel(), the code would then be:

return Arrays.stream(items).parallel().anyMatch(inputString::contains); 

Mapping two integers to one, in a unique and deterministic way

Although Stephan202's answer is the only truly general one, for integers in a bounded range you can do better. For example, if your range is 0..10,000, then you can do:

#define RANGE_MIN 0
#define RANGE_MAX 10000

unsigned int merge(unsigned int x, unsigned int y)
{
    return (x * (RANGE_MAX - RANGE_MIN + 1)) + y;
}

void split(unsigned int v, unsigned int &x, unsigned int &y)
{
    x = RANGE_MIN + (v / (RANGE_MAX - RANGE_MIN + 1));
    y = RANGE_MIN + (v % (RANGE_MAX - RANGE_MIN + 1));
}

Results can fit in a single integer for a range up to the square root of the integer type's cardinality. This packs slightly more efficiently than Stephan202's more general method. It is also considerably simpler to decode; requiring no square roots, for starters :)

ReactJS - .JS vs .JSX

JSX tags (<Component/>) are clearly not standard javascript and have no special meaning if you put them inside a naked <script> tag for example. Hence all React files that contain them are JSX and not JS.

By convention, the entry point of a React application is usually .js instead of .jsx even though it contains React components. It could as well be .jsx. Any other JSX files usually have the .jsx extension.

In any case, the reason there is ambiguity is because ultimately the extension does not matter much since the transpiler happily munches any kinds of files as long as they are actually JSX.

My advice would be: don't worry about it.

Split string and get first value only

Actually, there is a better way to do it than split:

public string GetFirstFromSplit(string input, char delimiter)
{
    var i = input.IndexOf(delimiter);

    return i == -1 ? input : input.Substring(0, i);
}

And as extension methods:

public static string FirstFromSplit(this string source, char delimiter)
{
    var i = source.IndexOf(delimiter);

    return i == -1 ? source : source.Substring(0, i);
}

public static string FirstFromSplit(this string source, string delimiter)
{
    var i = source.IndexOf(delimiter);

    return i == -1 ? source : source.Substring(0, i);
}

Usage:

string result = "hi, hello, sup".FirstFromSplit(',');
Console.WriteLine(result); // "hi"

Drawing an image from a data URL to a canvas

Perhaps this fiddle would help ThumbGen - jsFiddle It uses File API and Canvas to dynamically generate thumbnails of images.

(function (doc) {
    var oError = null;
    var oFileIn = doc.getElementById('fileIn');
    var oFileReader = new FileReader();
    var oImage = new Image();
    oFileIn.addEventListener('change', function () {
        var oFile = this.files[0];
        var oLogInfo = doc.getElementById('logInfo');
        var rFltr = /^(?:image\/bmp|image\/cis\-cod|image\/gif|image\/ief|image\/jpeg|image\/jpeg|image\/jpeg|image\/pipeg|image\/png|image\/svg\+xml|image\/tiff|image\/x\-cmu\-raster|image\/x\-cmx|image\/x\-icon|image\/x\-portable\-anymap|image\/x\-portable\-bitmap|image\/x\-portable\-graymap|image\/x\-portable\-pixmap|image\/x\-rgb|image\/x\-xbitmap|image\/x\-xpixmap|image\/x\-xwindowdump)$/i
        try {
            if (rFltr.test(oFile.type)) {
                oFileReader.readAsDataURL(oFile);
                oLogInfo.setAttribute('class', 'message info');
                throw 'Preview for ' + oFile.name;
            } else {
                oLogInfo.setAttribute('class', 'message error');
                throw oFile.name + ' is not a valid image';
            }
        } catch (err) {
            if (oError) {
                oLogInfo.removeChild(oError);
                oError = null;
                $('#logInfo').fadeOut();
                $('#imgThumb').fadeOut();
            }
            oError = doc.createTextNode(err);
            oLogInfo.appendChild(oError);
            $('#logInfo').fadeIn();
        }
    }, false);
    oFileReader.addEventListener('load', function (e) {
        oImage.src = e.target.result;
    }, false);
    oImage.addEventListener('load', function () {
        if (oCanvas) {
            oCanvas = null;
            oContext = null;
            $('#imgThumb').fadeOut();
        }
        var oCanvas = doc.getElementById('imgThumb');
        var oContext = oCanvas.getContext('2d');
        var nWidth = (this.width > 500) ? this.width / 4 : this.width;
        var nHeight = (this.height > 500) ? this.height / 4 : this.height;
        oCanvas.setAttribute('width', nWidth);
        oCanvas.setAttribute('height', nHeight);
        oContext.drawImage(this, 0, 0, nWidth, nHeight);
        $('#imgThumb').fadeIn();
    }, false);
})(document);

javascript date + 7 days

_x000D_
_x000D_
var future = new Date(); // get today date_x000D_
future.setDate(future.getDate() + 7); // add 7 days_x000D_
var finalDate = future.getFullYear() +'-'+ ((future.getMonth() + 1) < 10 ? '0' : '') + (future.getMonth() + 1) +'-'+ future.getDate();_x000D_
console.log(finalDate);
_x000D_
_x000D_
_x000D_

Import Script from a Parent Directory

You don't import scripts in Python you import modules. Some python modules are also scripts that you can run directly (they do some useful work at a module-level).

In general it is preferable to use absolute imports rather than relative imports.

toplevel_package/
+-- __init__.py
+-- moduleA.py
+-- subpackage
    +-- __init__.py
    +-- moduleB.py

In moduleB:

from toplevel_package import moduleA

If you'd like to run moduleB.py as a script then make sure that parent directory for toplevel_package is in your sys.path.

c++ Read from .csv file

That because your csv file is in invalid format, maybe the line break in your text file is not the \n or \r

and, using c/c++ to parse text is not a good idea. try awk:

 $awk -F"," '{print "ID="$1"\tName="$2"\tAge="$3"\tGender="$4}' 1.csv
 ID=0   Name=Filipe Age=19  Gender=M
 ID=1   Name=Maria  Age=20  Gender=F
 ID=2   Name=Walter Age=60  Gender=M

Check if a given key already exists in a dictionary and increment it

You need the key in dict idiom for that.

if key in my_dict and not (my_dict[key] is None):
  # do something
else:
  # do something else

However, you should probably consider using defaultdict (as dF suggested).

How to set up a cron job to run an executable every hour?

Since I could not run the C executable that way, I wrote a simple shell script that does the following

cd /..path_to_shell_script
./c_executable_name

In the cron jobs list, I call the shell script.

Gradle sync failed: failed to find Build Tools revision 24.0.0 rc1

Android Studio updating didn't work for me. So I updated it manually. Go to your sdk location, run SDK Manager, mark desired build tools version and install.

Jquery assiging class to th in a table

You had thead in your selector, but there is no thead in your table. Also you had your selectors backwards. As you mentioned above, you wanted to be adding the tr class to the th, not vice-versa (although your comment seems to contradict what you wrote up above).

$('tr th').each(function(index){     if($('tr td').eq(index).attr('class') != ''){         // get the class of the td         var tdClass = $('tr td').eq(index).attr('class');         // add it to this th         $(this).addClass(tdClass );     } }); 

Fiddle

Plot mean and standard deviation

You may find an answer with this example : errorbar_demo_features.py

"""
Demo of errorbar function with different ways of specifying error bars.

Errors can be specified as a constant value (as shown in `errorbar_demo.py`),
or as demonstrated in this example, they can be specified by an N x 1 or 2 x N,
where N is the number of data points.

N x 1:
    Error varies for each point, but the error values are symmetric (i.e. the
    lower and upper values are equal).

2 x N:
    Error varies for each point, and the lower and upper limits (in that order)
    are different (asymmetric case)

In addition, this example demonstrates how to use log scale with errorbar.
"""
import numpy as np
import matplotlib.pyplot as plt

# example data
x = np.arange(0.1, 4, 0.5)
y = np.exp(-x)
# example error bar values that vary with x-position
error = 0.1 + 0.2 * x
# error bar values w/ different -/+ errors
lower_error = 0.4 * error
upper_error = error
asymmetric_error = [lower_error, upper_error]

fig, (ax0, ax1) = plt.subplots(nrows=2, sharex=True)
ax0.errorbar(x, y, yerr=error, fmt='-o')
ax0.set_title('variable, symmetric error')

ax1.errorbar(x, y, xerr=asymmetric_error, fmt='o')
ax1.set_title('variable, asymmetric error')
ax1.set_yscale('log')
plt.show()

Which plots this:

enter image description here

Inputting a default image in case the src attribute of an html <img> is not valid?

I don't think it is possible using just HTML. However using javascript this should be doable. Bassicly we loop over each image, test if it is complete and if it's naturalWidth is zero then that means that it not found. Here is the code:

fixBrokenImages = function( url ){
    var img = document.getElementsByTagName('img');
    var i=0, l=img.length;
    for(;i<l;i++){
        var t = img[i];
        if(t.naturalWidth === 0){
            //this image is broken
            t.src = url;
        }
    }
}

Use it like this:

 window.onload = function() {
    fixBrokenImages('example.com/image.png');
 }

Tested in Chrome and Firefox

How to select rows with one or more nulls from a pandas DataFrame without listing columns explicitly?

def nans(df): return df[df.isnull().any(axis=1)]

then when ever you need it you can type:

nans(your_dataframe)

How to clear basic authentication details in chrome

Things changed a lot since the answer was posted. Now you will see a small key symbol on the right hand side of the URL bar.
Click the symbol and it will take you directly to the saved password dialog where you can remove the password.

Successfully tested in Chrome 49

Passing struct to function

The line function implementation should be:

void addStudent(struct student person) {

}

person is not a type but a variable, you cannot use it as the type of a function parameter.

Also, make sure your struct is defined before the prototype of the function addStudent as the prototype uses it.

SQL: Return "true" if list of records exists?

You can use a SELECT CASE statement like so:

select case when EXISTS (
 select 1 
 from <table>
 where <condition>
 ) then TRUE else FALSE end

It returns TRUE when your query in the parents exists.

Update value of a nested dictionary of varying depth

you could try this, it works with lists and is pure:

def update_keys(newd, dic, mapping):
  def upsingle(d,k,v):
    if k in mapping:
      d[mapping[k]] = v
    else:
      d[k] = v
  for ekey, evalue in dic.items():
    upsingle(newd, ekey, evalue)
    if type(evalue) is dict:
      update_keys(newd, evalue, mapping)
    if type(evalue) is list:
      upsingle(newd, ekey, [update_keys({}, i, mapping) for i in evalue])
  return newd

Appending items to a list of lists in python

import csv
cols = [' V1', ' I1'] # define your columns here, check the spaces!
data = [[] for col in cols] # this creates a list of **different** lists, not a list of pointers to the same list like you did in [[]]*len(positions) 
with open('data.csv', 'r') as f:
    for rec in csv.DictReader(f):
        for l, col in zip(data, cols):
            l.append(float(rec[col]))
print data

# [[3.0, 3.0], [0.01, 0.01]]

Multiple WHERE Clauses with LINQ extension methods

results = context.Orders.Where(o => o.OrderDate <= today && today <= o.OrderDate)

The select is uneeded as you are already working with an order.

Change keystore password from no password to a non blank password

Add -storepass to keytool arguments.

keytool -storepasswd -storepass '' -keystore mykeystore.jks

But also notice that -list command does not always require a password. I could execute follow command in both cases: without password or with valid password

$JAVA_HOME/bin/keytool -list -keystore $JAVA_HOME/jre/lib/security/cacerts

jQuery lose focus event

Use blur event to call your function when element loses focus :

$('#filter').blur(function() {
  $('#options').hide();
});

GCC -fPIC option

Code that is built into shared libraries should normally be position-independent code, so that the shared library can readily be loaded at (more or less) any address in memory. The -fPIC option ensures that GCC produces such code.

td widths, not working?

You can try the "table-layout: fixed;" to your table

table-layout: fixed;
width: 150px;

150px or your desired width.

Reference: https://css-tricks.com/fixing-tables-long-strings/

Get first row of dataframe in Python Pandas based on criteria

This tutorial is a very good one for pandas slicing. Make sure you check it out. Onto some snippets... To slice a dataframe with a condition, you use this format:

>>> df[condition]

This will return a slice of your dataframe which you can index using iloc. Here are your examples:

  1. Get first row where A > 3 (returns row 2)

    >>> df[df.A > 3].iloc[0]
    A    4
    B    6
    C    3
    Name: 2, dtype: int64
    

If what you actually want is the row number, rather than using iloc, it would be df[df.A > 3].index[0].

  1. Get first row where A > 4 AND B > 3:

    >>> df[(df.A > 4) & (df.B > 3)].iloc[0]
    A    5
    B    4
    C    5
    Name: 4, dtype: int64
    
  2. Get first row where A > 3 AND (B > 3 OR C > 2) (returns row 2)

    >>> df[(df.A > 3) & ((df.B > 3) | (df.C > 2))].iloc[0]
    A    4
    B    6
    C    3
    Name: 2, dtype: int64
    

Now, with your last case we can write a function that handles the default case of returning the descending-sorted frame:

>>> def series_or_default(X, condition, default_col, ascending=False):
...     sliced = X[condition]
...     if sliced.shape[0] == 0:
...         return X.sort_values(default_col, ascending=ascending).iloc[0]
...     return sliced.iloc[0]
>>> 
>>> series_or_default(df, df.A > 6, 'A')
A    5
B    4
C    5
Name: 4, dtype: int64

As expected, it returns row 4.

How to add/subtract time (hours, minutes, etc.) from a Pandas DataFrame.Index whos objects are of type datetime.time?

This one worked for me:

>> print(df)
                          TotalVolume  Symbol
2016-04-15 09:00:00       108400       2802.T
2016-04-15 09:05:00       50300        2802.T

>> print(df.set_index(pd.to_datetime(df.index.values) - datetime(2016, 4, 15)))

             TotalVolume  Symbol
09:00:00     108400       2802.T
09:05:00     50300        2802.T

Get Country of IP Address with PHP

You can use https://ip-api.io/ to get country name, city name, latitude and longitude. It supports IPv6.

As a bonus it will tell if ip address is a tor node, public proxy or spammer.

Php Code:

$result = json_decode(file_get_contents('http://ip-api.io/json/64.30.228.118'));
var_dump($result);

Output:

{
"ip": "64.30.228.118",
"country_code": "US",
"country_name": "United States",
"region_code": "FL",
"region_name": "Florida",
"city": "Fort Lauderdale",
"zip_code": "33309",
"time_zone": "America/New_York",
"latitude": 26.1882,
"longitude": -80.1711,
"metro_code": 528,
"suspicious_factors": {
"is_proxy": false,
"is_tor_node": false,
"is_spam": false,
"is_suspicious": false
}

Load jQuery with Javascript and use jQuery

From the DevTools console, you can run:

document.getElementsByTagName("head")[0].innerHTML += '<script type="text/javascript" src="//ajax.googleapis.com/ajax/libs/jquery/3.4.1/jquery.min.js"><\/script>';

Check the available jQuery version at https://code.jquery.com/jquery/.

To check whether it's loaded, see: Checking if jquery is loaded using Javascript.

How to add a browser tab icon (favicon) for a website?

<link rel="shortcut icon" 
href="http://someWebsiteLocation/images/imageName.ico">

If i may add more clarity for those of you that are still confused. The .ico file tends to provide more transparency than the .png, which is why i recommend converting your image here as mentioned above: http://www.favicomatic.com/done also, inside the href is just the location of the image, it can be any server location, remember to add the http:// in front, otherwise it won't work.

How can I easily view the contents of a datatable or dataview in the immediate window

I've not tried it myself, but Visual Studio 2005 (and later) support the concept of Debugger Visualizers. This allows you to customize how an object is shown in the IDE. Check out this article for more details.

http://davidhayden.com/blog/dave/archive/2005/12/26/2645.aspx

Android Saving created bitmap to directory on sd card

Pass bitmap to the saveImage Method, It will save your bitmap in the name of a saveBitmap, inside created test folder.

private void saveImage(Bitmap data) {
                    File createFolder = new File(Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_PICTURES),"test");
                    if(!createFolder.exists())
                    createFolder.mkdir();
                    File saveImage = new File(createFolder,"saveBitmap.jpg");
                    try {
                        OutputStream outputStream = new FileOutputStream(saveImage);
                        data.compress(Bitmap.CompressFormat.JPEG,100,outputStream);
                        outputStream.flush();
                        outputStream.close();
                    } catch (FileNotFoundException e) {
                        e.printStackTrace();
                    } catch (IOException e) {
                        e.printStackTrace();
                    }
                }

and use this:

  saveImage(bitmap);

.trim() in JavaScript not working in IE

Unfortunately there is not cross browser JavaScript support for trim().

If you aren't using jQuery (which has a .trim() method) you can use the following methods to add trim support to strings:

String.prototype.trim = function() {
    return this.replace(/^\s+|\s+$/g,"");
}
String.prototype.ltrim = function() {
    return this.replace(/^\s+/,"");
}
String.prototype.rtrim = function() {
    return this.replace(/\s+$/,"");
}

jQuery.each - Getting li elements inside an ul

$(function() {
    $('.phrase .items').each(function(i, items_list){
        var myText = "";

        $(items_list).find('li').each(function(j, li){
            alert(li.text());
        })

        alert(myText);

    });
};

How can I use iptables on centos 7?

I modified the /etc/sysconfig/ip6tables-config file changing:

IP6TABLES_SAVE_ON_STOP="no"

To:

IP6TABLES_SAVE_ON_STOP="yes"

And this:

IP6TABLES_SAVE_ON_RESTART="no"

To:

IP6TABLES_SAVE_ON_RESTART="yes"

This seemed to save the changes I made using the iptables commands through a reboot.

Remove all items from a FormArray in Angular

I never tried using formArray, I have always worked with FormGroup, and you can remove all controls using:

Object.keys(this.formGroup.controls).forEach(key => {
          this.formGroup.removeControl(key);
        });

being formGroup an instance of FormGroup.

Strange PostgreSQL "value too long for type character varying(500)"

By specifying the column as VARCHAR(500) you've set an explicit 500 character limit. You might not have done this yourself explicitly, but Django has done it for you somewhere. Telling you where is hard when you haven't shown your model, the full error text, or the query that produced the error.

If you don't want one, use an unqualified VARCHAR, or use the TEXT type.

varchar and text are limited in length only by the system limits on column size - about 1GB - and by your memory. However, adding a length-qualifier to varchar sets a smaller limit manually. All of the following are largely equivalent:

column_name VARCHAR(500)

column_name VARCHAR CHECK (length(column_name) <= 500) 

column_name TEXT CHECK (length(column_name) <= 500) 

The only differences are in how database metadata is reported and which SQLSTATE is raised when the constraint is violated.

The length constraint is not generally obeyed in prepared statement parameters, function calls, etc, as shown:

regress=> \x
Expanded display is on.
regress=> PREPARE t2(varchar(500)) AS SELECT $1;
PREPARE
regress=> EXECUTE t2( repeat('x',601) );
-[ RECORD 1 ]-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
?column? | xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx

and in explicit casts it result in truncation:

regress=> SELECT repeat('x',501)::varchar(1);
-[ RECORD 1 ]
repeat | x

so I think you are using a VARCHAR(500) column, and you're looking at the wrong table or wrong instance of the database.

How to duplicate a git repository? (without forking)

I have noticed some of the other answers here use a bare clone and then mirror push to the new repository, however this does not work for me and when I open the new repository after that, the files look mixed up and not as I expect.

Here is a solution that definitely works for copying the files, although it does not preserve the original repository's revision history.

  1. git clone the repository onto your local machine.
  2. cd into the project directory and then run rm -rf .git to remove all the old git metadata including commit history, etc.
  3. Initialize a fresh git repository by running git init.
  4. Run git add . ; git commit -am "Initial commit" - Of course you can call this commit what you want.
  5. Set the origin to your new repository git remote add origin https://github.com/user/repo-name (replace the url with the url to your new repository)
  6. Push it to your new repository with git push origin master.

NullInjectorError: No provider for AngularFirestore

I solved this problem by just removing firestore from:

import { AngularFirestore } from '@angular/fire/firestore/firestore';

in my component.ts file. as use only:

import { AngularFirestore } from '@angular/fire/firestore';

this can be also your problem.

Get The Current Domain Name With Javascript (Not the path, etc.)

If you wish a full domain origin, you can use this:

document.location.origin

And if you wish to get only the domain, use can you just this:

document.location.hostname

But you have other options, take a look at the properties in:

document.location

How to use a decimal range() step value?

And if you do this often, you might want to save the generated list r

r=map(lambda x: x/10.0,range(0,10))
for i in r:
    print i

How to calculate the difference between two dates using PHP?

Very simple:

    <?php
        $date1 = date_create("2007-03-24");
        echo "Start date: ".$date1->format("Y-m-d")."<br>";
        $date2 = date_create("2009-06-26");
        echo "End date: ".$date2->format("Y-m-d")."<br>";
        $diff = date_diff($date1,$date2);
        echo "Difference between start date and end date: ".$diff->format("%y years, %m months and %d days")."<br>";
    ?>

Please checkout the following link for details:

PHP: date_diff - Manual

Note that it's for PHP 5.3.0 or greater.

Find CRLF in Notepad++

To change a document of separate lines into a single line, with each line forming one entry in a comma separated list:

  1. ctrl+f to open the search/replacer.
  2. Click the "Replace" tab.
  3. Fill the "Find what" entry with "\r\n".
  4. Fill the "Replace with" entry with "," or ", " (depending on preference).
  5. Un-check the "Match whole word" checkbox (the important bit that eludes logic).
  6. Check the "Extended" radio button.
  7. Click the "Replace all" button.

These steps turn e.g.

foo bar

bar baz

baz foo

into:

foo bar,bar baz,baz foo

or: (depending on preference)

foo bar, bar baz, baz foo

What is let-* in Angular 2 templates?

The Angular microsyntax lets you configure a directive in a compact, friendly string. The microsyntax parser translates that string into attributes on the <ng-template>. The let keyword declares a template input variable that you reference within the template.

javascript regex for password containing at least 8 characters, 1 number, 1 upper and 1 lowercase

Using individual regular expressions to test the different parts would be considerably easier than trying to get one single regular expression to cover all of them. It also makes it easier to add or remove validation criteria.

Note, also, that your usage of .filter() was incorrect; it will always return a jQuery object (which is considered truthy in JavaScript). Personally, I'd use an .each() loop to iterate over all of the inputs, and report individual pass/fail statuses. Something like the below:

$(".buttonClick").click(function () {

    $("input[type=text]").each(function () {
        var validated =  true;
        if(this.value.length < 8)
            validated = false;
        if(!/\d/.test(this.value))
            validated = false;
        if(!/[a-z]/.test(this.value))
            validated = false;
        if(!/[A-Z]/.test(this.value))
            validated = false;
        if(/[^0-9a-zA-Z]/.test(this.value))
            validated = false;
        $('div').text(validated ? "pass" : "fail");
        // use DOM traversal to select the correct div for this input above
    });
});

Working demo

DATEDIFF function in Oracle

Just subtract the two dates:

select date '2000-01-02' - date '2000-01-01' as dateDiff
from dual;

The result will be the difference in days.

More details are in the manual:
https://docs.oracle.com/cd/E11882_01/server.112/e41084/sql_elements001.htm#i48042

What is the use of rt.jar file in java?

rt.jar contains all of the compiled class files for the base Java Runtime environment. You should not be messing with this jar file.

For MacOS it is called classes.jar and located under /System/Library/Frameworks/<java_version>/Classes . Same not messing with it rule applies there as well :).

http://javahowto.blogspot.com/2006/05/what-does-rtjar-stand-for-in.html

Java Read Large Text File With 70million line of text

In Java 8, for anyone looking now to read file large files line by line,

Stream<String> lines = Files.lines(Paths.get("c:\myfile.txt"));
lines.forEach(l -> {
  // Do anything line by line   
});

Resizing Images in VB.NET

    Dim x As Integer = 0
    Dim y As Integer = 0
    Dim k = 0
    Dim l = 0
    Dim bm As New Bitmap(p1.Image)
    Dim om As New Bitmap(p1.Image.Width, p1.Image.Height)
    Dim r, g, b As Byte
    Do While x < bm.Width - 1
        y = 0
        l = 0
        Do While y < bm.Height - 1
            r = 255 - bm.GetPixel(x, y).R
            g = 255 - bm.GetPixel(x, y).G
            b = 255 - bm.GetPixel(x, y).B
            om.SetPixel(k, l, Color.FromArgb(r, g, b))
            y += 3
            l += 1
        Loop
        x += 3
        k += 1
    Loop
    p2.Image = om

How to install node.js as windows service?

https://nssm.cc/ service helper good for create windows service by batch file i use from nssm & good working for any app & any file

Best way to serialize/unserialize objects in JavaScript?

I tried to do this with Date with native JSON...

function stringify (obj: any) {
  return JSON.stringify(
    obj,
    function (k, v) {
      if (this[k] instanceof Date) {
        return ['$date', +this[k]]
      }
      return v
    }
  )
}

function clone<T> (obj: T): T {
  return JSON.parse(
    stringify(obj),
    (_, v) => (Array.isArray(v) && v[0] === '$date') ? new Date(v[1]) : v
  )
}

What does this say? It says

  • There needs to be a unique identifier, better than $date, if you want it more secure.
class Klass {
  static fromRepr (repr: string): Klass {
    return new Klass(...)
  }

  static guid = '__Klass__'

  __repr__ (): string {
    return '...'
  }
}

This is a serializable Klass, with

function serialize (obj: any) {
  return JSON.stringify(
    obj,
    function (k, v) { return this[k] instanceof Klass ? [Klass.guid, this[k].__repr__()] : v }
  )
}

function deserialize (repr: string) {
  return JSON.parse(
    repr,
    (_, v) => (Array.isArray(v) && v[0] === Klass.guid) ? Klass.fromRepr(v[1]) : v
  )
}

I tried to do it with Mongo-style Object ({ $date }) as well, but it failed in JSON.parse. Supplying k doesn't matter anymore...

BTW, if you don't care about libraries, you can use yaml.dump / yaml.load from js-yaml. Just make sure you do it the dangerous way.

Undo git update-index --assume-unchanged <file>

If this is a command that you use often - you may want to consider having an alias for it as well. Add to your global .gitconfig:

[alias]
    hide = update-index --assume-unchanged
    unhide = update-index --no-assume-unchanged

How to set an alias (if you don't know already):

git config --configLocation alias.aliasName 'command --options'

Example:

git config --global alias.hide 'update-index --assume-unchanged'
git config... etc

After saving this to your .gitconfig, you can run a cleaner command.

git hide myfile.ext

or

git unhide myfile.ext

This git documentation was very helpful.

As per the comments, this is also a helpful alias to find out what files are currently being hidden:

[alias]
    hidden = ! git ls-files -v | grep '^h' | cut -c3-

How to embed small icon in UILabel

Swift 5 Easy Way Just CopyPaste and change what you want

let fullString = NSMutableAttributedString(string:"To start messaging contacts who have Talklo, tap ")

 // create our NSTextAttachment
let image1Attachment = NSTextAttachment() 
image1Attachment.image = UIImage(named: "chatEmoji")
image1Attachment.bounds = CGRect(x: 0, y: -8, width: 25, height: 25)

// wrap the attachment in its own attributed string so we can append it
let image1String = NSAttributedString(attachment: image1Attachment)

 // add the NSTextAttachment wrapper to our full string, then add some more text.

 fullString.append(image1String)
 fullString.append(NSAttributedString(string:" at the right bottom of your screen"))

 // draw the result in a label
 self.lblsearching.attributedText = fullString

enter image description here

How do I get and set Environment variables in C#?

I could be able to update the environment variable by using the following

string EnvPath = System.Environment.GetEnvironmentVariable("PATH", EnvironmentVariableTarget.Machine) ?? string.Empty;
if (!string.IsNullOrEmpty(EnvPath) && !EnvPath .EndsWith(";"))
    EnvPath = EnvPath + ';';
EnvPath = EnvPath + @"C:\Test";
Environment.SetEnvironmentVariable("PATH", EnvPath , EnvironmentVariableTarget.Machine);

Get column index from column name in python pandas

In case you want the column name from the column location (the other way around to the OP question), you can use:

>>> df.columns.get_values()[location]

Using @DSM Example:

>>> df = DataFrame({"pear": [1,2,3], "apple": [2,3,4], "orange": [3,4,5]})

>>> df.columns

Index(['apple', 'orange', 'pear'], dtype='object')

>>> df.columns.get_values()[1]

'orange'

Other ways:

df.iloc[:,1].name

df.columns[location] #(thanks to @roobie-nuby for pointing that out in comments.) 

Width equal to content

The solution with inline-block forces you to insert <br> after each element.
The solution with float forces you to wrap all elements with "clearfix" div.

Another elegant solution is to use display: table for elements.

With this solution you don't need to insert line breaks manually (like with inline-block), you don't need a wrapper around your elements (like with floats) and you can center your element if you need.

http://jsfiddle.net/8md3jy4r/3/

Removing single-quote from a string in php

You can substitute in HTML entitiy:

$FileName = preg_replace("/'/", "\&#39;", $UserInput);

How to create a batch file to run cmd as administrator

You can use a shortcut that links to the batch file. Just go into properties for the shortcut and select advanced, then "run as administrator".

Then just make the batch file hidden, and run the shortcut.

This way, you can even set your own icon for the shortcut.

Clear MySQL query cache without restarting server

according the documentation, this should do it...

RESET QUERY CACHE 

how to dynamically add options to an existing select in vanilla javascript

This tutorial shows exactly what you need to do: Add options to an HTML select box with javascript

Basically:

 daySelect = document.getElementById('daySelect');
 daySelect.options[daySelect.options.length] = new Option('Text 1', 'Value1');

Node.js check if path is file or directory

Update: Node.Js >= 10

We can use the new fs.promises API

const fs = require('fs').promises;

(async() => {
    const stat = await fs.lstat('test.txt');
    console.log(stat.isFile());
})().catch(console.error)

Any Node.Js version

Here's how you would detect if a path is a file or a directory asynchronously, which is the recommended approach in node. using fs.lstat

const fs = require("fs");

let path = "/path/to/something";

fs.lstat(path, (err, stats) => {

    if(err)
        return console.log(err); //Handle error

    console.log(`Is file: ${stats.isFile()}`);
    console.log(`Is directory: ${stats.isDirectory()}`);
    console.log(`Is symbolic link: ${stats.isSymbolicLink()}`);
    console.log(`Is FIFO: ${stats.isFIFO()}`);
    console.log(`Is socket: ${stats.isSocket()}`);
    console.log(`Is character device: ${stats.isCharacterDevice()}`);
    console.log(`Is block device: ${stats.isBlockDevice()}`);
});

Note when using the synchronous API:

When using the synchronous form any exceptions are immediately thrown. You can use try/catch to handle exceptions or allow them to bubble up.

try{
     fs.lstatSync("/some/path").isDirectory()
}catch(e){
   // Handle error
   if(e.code == 'ENOENT'){
     //no such file or directory
     //do something
   }else {
     //do something else
   }
}

Convert date to UTC using moment.js

Don't you need something to compare and then retrieve the milliseconds?

For instance:

let enteredDate = $("#txt-date").val(); // get the date entered in the input
let expires = moment.utc(enteredDate); // convert it into UTC

With that you have the expiring date in UTC. Now you can get the "right-now" date in UTC and compare:

var rightNowUTC = moment.utc(); // get this moment in UTC based on browser
let duration = moment.duration(rightNowUTC.diff(expires)); // get the diff
let remainingTimeInMls = duration.asMilliseconds();

Deleting row from datatable in C#

Advance for loop works better for this case

public void deleteRow(DataRow selectedRow)
        {
            foreach (DataRow  in StudentTable.Rows)
            {
                if (SR[TableColumn.StudentID.ToString()].ToString() == StudentIndex)
                    SR.Delete();
            }

            StudentTable.AcceptChanges();
        }

pandas: How do I split text in a column into multiple rows?

It may be late to answer this question but I hope to document 2 good features from Pandas: pandas.Series.str.split() with regular expression and pandas.Series.explode().

import pandas as pd
import numpy as np

df = pd.DataFrame(
    {'CustNum': [32363, 31316],
     'CustomerName': ['McCartney, Paul', 'Lennon, John'],
     'ItemQty': [3, 25],
     'Item': ['F04', 'F01'],
     'Seatblocks': ['2:218:10:4,6', '1:13:36:1,12 1:13:37:1,13'],
     'ItemExt': [60, 360]
    }
)

print(df)
print('-'*80+'\n')

df['Seatblocks'] = df['Seatblocks'].str.split('[ :]')
df = df.explode('Seatblocks').reset_index(drop=True)
cols = list(df.columns)
cols.append(cols.pop(cols.index('CustomerName')))
df = df[cols]


print(df)
print('='*80+'\n')
print(df[df['CustomerName'] == 'Lennon, John'])

The output is:

   CustNum     CustomerName  ItemQty Item                 Seatblocks  ItemExt
0    32363  McCartney, Paul        3  F04               2:218:10:4,6       60
1    31316     Lennon, John       25  F01  1:13:36:1,12 1:13:37:1,13      360
--------------------------------------------------------------------------------

    CustNum  ItemQty Item Seatblocks  ItemExt     CustomerName
0     32363        3  F04          2       60  McCartney, Paul
1     32363        3  F04        218       60  McCartney, Paul
2     32363        3  F04         10       60  McCartney, Paul
3     32363        3  F04        4,6       60  McCartney, Paul
4     31316       25  F01          1      360     Lennon, John
5     31316       25  F01         13      360     Lennon, John
6     31316       25  F01         36      360     Lennon, John
7     31316       25  F01       1,12      360     Lennon, John
8     31316       25  F01          1      360     Lennon, John
9     31316       25  F01         13      360     Lennon, John
10    31316       25  F01         37      360     Lennon, John
11    31316       25  F01       1,13      360     Lennon, John
================================================================================

    CustNum  ItemQty Item Seatblocks  ItemExt  CustomerName
4     31316       25  F01          1      360  Lennon, John
5     31316       25  F01         13      360  Lennon, John
6     31316       25  F01         36      360  Lennon, John
7     31316       25  F01       1,12      360  Lennon, John
8     31316       25  F01          1      360  Lennon, John
9     31316       25  F01         13      360  Lennon, John
10    31316       25  F01         37      360  Lennon, John
11    31316       25  F01       1,13      360  Lennon, John

How to create a DataTable in C# and how to add rows?

You can add Row in a single line

    DataTable table = new DataTable();
    table.Columns.Add("Dosage", typeof(int));
    table.Columns.Add("Drug", typeof(string));
    table.Columns.Add("Patient", typeof(string));
    table.Columns.Add("Date", typeof(DateTime));

    // Here we add five DataRows.
    table.Rows.Add(25, "Indocin", "David", DateTime.Now);
    table.Rows.Add(50, "Enebrel", "Sam", DateTime.Now);
    table.Rows.Add(10, "Hydralazine", "Christoff", DateTime.Now);
    table.Rows.Add(21, "Combivent", "Janet", DateTime.Now);
    table.Rows.Add(100, "Dilantin", "Melanie", DateTime.Now);

Getting IP address of client

As @martin and this answer explained, it is complicated. There is no bullet-proof way of getting the client's ip address.

The best that you can do is to try to parse "X-Forwarded-For" and rely on request.getRemoteAddr();

public static String getClientIpAddress(HttpServletRequest request) {
    String xForwardedForHeader = request.getHeader("X-Forwarded-For");
    if (xForwardedForHeader == null) {
        return request.getRemoteAddr();
    } else {
        // As of https://en.wikipedia.org/wiki/X-Forwarded-For
        // The general format of the field is: X-Forwarded-For: client, proxy1, proxy2 ...
        // we only want the client
        return new StringTokenizer(xForwardedForHeader, ",").nextToken().trim();
    }
}

SQL Update with row_number()

Simple and easy way to update the cursor

UPDATE Cursor
SET Cursor.CODE = Cursor.New_CODE
FROM (
  SELECT CODE, ROW_NUMBER() OVER (ORDER BY [CODE]) AS New_CODE
  FROM Table Where CODE BETWEEN 1000 AND 1999
  ) Cursor

Android SDK folder taking a lot of disk space. Do we need to keep all of the System Images?

System images are pre-installed Android operating systems, and are only used by emulators. If you use your real Android device for debugging, you no longer need them, so you can remove them all.

The cleanest way to remove them is using SDK Manager. Open up SDK Manager and uncheck those system images and then apply.

Also feel free to remove other components (e.g. old SDK levels) that are of no use.

jQuery checkbox change and click event

Late answer, but you can also use on("change")

_x000D_
_x000D_
$('#check').on('change', function() {
     var checked = this.checked
    $('span').html(checked.toString())
});
_x000D_
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<input type="checkbox" id="check"> <span>Check me!</span>
_x000D_
_x000D_
_x000D_

Express.js - app.listen vs server.listen

Just for punctuality purpose and extend a bit Tim answer.
From official documentation:

The app returned by express() is in fact a JavaScript Function, DESIGNED TO BE PASSED to Node’s HTTP servers as a callback to handle requests.

This makes it easy to provide both HTTP and HTTPS versions of your app with the same code base, as the app does not inherit from these (it is simply a callback):

http.createServer(app).listen(80);
https.createServer(options, app).listen(443);

The app.listen() method returns an http.Server object and (for HTTP) is a convenience method for the following:

app.listen = function() {
  var server = http.createServer(this);
  return server.listen.apply(server, arguments);
};

MySQL: Fastest way to count number of rows

I've always understood that the below will give me the fastest response times.

SELECT COUNT(1) FROM ... WHERE ...

How to make bootstrap column height to 100% row height?

You can solve that using display table.

Here is the updated JSFiddle that solves your problem.

CSS

.body {
    display: table;
    background-color: green;
}

.left-side {
    background-color: blue;
    float: none;
    display: table-cell;
    border: 1px solid;
}

.right-side {
    background-color: red;
    float: none;
    display: table-cell;
    border: 1px solid;
}

HTML

<div class="row body">
        <div class="col-xs-9 left-side">
            <p>sdfsdf</p>
            <p>sdfsdf</p>
            <p>sdfsdf</p>
            <p>sdfsdf</p>
            <p>sdfsdf</p>
            <p>sdfsdf</p>
        </div>
        <div class="col-xs-3 right-side">
            asdfdf
        </div>
    </div>

How does setTimeout work in Node.JS?

The only way to ensure code is executed is to place your setTimeout logic in a different process.

Use the child process module to spawn a new node.js program that does your logic and pass data to that process through some kind of a stream (maybe tcp).

This way even if some long blocking code is running in your main process your child process has already started itself and placed a setTimeout in a new process and a new thread and will thus run when you expect it to.

Further complication are at a hardware level where you have more threads running then processes and thus context switching will cause (very minor) delays from your expected timing. This should be neglible and if it matters you need to seriously consider what your trying to do, why you need such accuracy and what kind of real time alternative hardware is available to do the job instead.

In general using child processes and running multiple node applications as separate processes together with a load balancer or shared data storage (like redis) is important for scaling your code.

Regex for password must contain at least eight characters, at least one number and both lower and uppercase letters and special characters

This worked for me:

^(?=.*[0-9])(?=.*[a-z])(?=.*[A-Z])(?=.*[@$!%*?&])([a-zA-Z0-9@$!%*?&]{8,})$
  • At least 8 characters long;
  • One lowercase, one uppercase, one number and one special character;
  • No whitespaces.

Oracle 'Partition By' and 'Row_Number' keyword

PARTITION BY segregate sets, this enables you to be able to work(ROW_NUMBER(),COUNT(),SUM(),etc) on related set independently.

In your query, the related set comprised of rows with similar cdt.country_code, cdt.account, cdt.currency. When you partition on those columns and you apply ROW_NUMBER on them. Those other columns on those combination/set will receive sequential number from ROW_NUMBER

But that query is funny, if your partition by some unique data and you put a row_number on it, it will just produce same number. It's like you do an ORDER BY on a partition that is guaranteed to be unique. Example, think of GUID as unique combination of cdt.country_code, cdt.account, cdt.currency

newid() produces GUID, so what shall you expect by this expression?

select
   hi,ho,
   row_number() over(partition by newid() order by hi,ho)
from tbl;

...Right, all the partitioned(none was partitioned, every row is partitioned in their own row) rows' row_numbers are all set to 1

Basically, you should partition on non-unique columns. ORDER BY on OVER needed the PARTITION BY to have a non-unique combination, otherwise all row_numbers will become 1

An example, this is your data:

create table tbl(hi varchar, ho varchar);

insert into tbl values
('A','X'),
('A','Y'),
('A','Z'),
('B','W'),
('B','W'),
('C','L'),
('C','L');

Then this is analogous to your query:

select
   hi,ho,
   row_number() over(partition by hi,ho order by hi,ho)
from tbl;

What will be the output of that?

HI  HO  COLUMN_2
A   X   1
A   Y   1
A   Z   1
B   W   1
B   W   2
C   L   1
C   L   2

You see thee combination of HI HO? The first three rows has unique combination, hence they are set to 1, the B rows has same W, hence different ROW_NUMBERS, likewise with HI C rows.

Now, why is the ORDER BY needed there? If the previous developer merely want to put a row_number on similar data (e.g. HI B, all data are B-W, B-W), he can just do this:

select
   hi,ho,
   row_number() over(partition by hi,ho)
from tbl;

But alas, Oracle(and Sql Server too) doesn't allow partition with no ORDER BY; whereas in Postgresql, ORDER BY on PARTITION is optional: http://www.sqlfiddle.com/#!1/27821/1

select
   hi,ho,
   row_number() over(partition by hi,ho)
from tbl;

Your ORDER BY on your partition look a bit redundant, not because of the previous developer's fault, some database just don't allow PARTITION with no ORDER BY, he might not able find a good candidate column to sort on. If both PARTITION BY columns and ORDER BY columns are the same just remove the ORDER BY, but since some database don't allow it, you can just do this:

SELECT cdt.*,
        ROW_NUMBER ()
        OVER (PARTITION BY cdt.country_code, cdt.account, cdt.currency
              ORDER BY newid())
           seq_no
   FROM CUSTOMER_DETAILS cdt

You cannot find a good column to use for sorting similar data? You might as well sort on random, the partitioned data have the same values anyway. You can use GUID for example(you use newid() for SQL Server). So that has the same output made by previous developer, it's unfortunate that some database doesn't allow PARTITION with no ORDER BY

Though really, it eludes me and I cannot find a good reason to put a number on the same combinations (B-W, B-W in example above). It's giving the impression of database having redundant data. Somehow reminded me of this: How to get one unique record from the same list of records from table? No Unique constraint in the table

It really looks arcane seeing a PARTITION BY with same combination of columns with ORDER BY, can not easily infer the code's intent.

Live test: http://www.sqlfiddle.com/#!3/27821/6


But as dbaseman have noticed also, it's useless to partition and order on same columns.

You have a set of data like this:

create table tbl(hi varchar, ho varchar);

insert into tbl values
('A','X'),
('A','X'),
('A','X'),
('B','Y'),
('B','Y'),
('C','Z'),
('C','Z');

Then you PARTITION BY hi,ho; and then you ORDER BY hi,ho. There's no sense numbering similar data :-) http://www.sqlfiddle.com/#!3/29ab8/3

select
   hi,ho,
   row_number() over(partition by hi,ho order by hi,ho) as nr
from tbl;

Output:

HI  HO  ROW_QUERY_A
A   X   1
A   X   2
A   X   3
B   Y   1
B   Y   2
C   Z   1
C   Z   2

See? Why need to put row numbers on same combination? What you will analyze on triple A,X, on double B,Y, on double C,Z? :-)


You just need to use PARTITION on non-unique column, then you sort on non-unique column(s)'s unique-ing column. Example will make it more clear:

create table tbl(hi varchar, ho varchar);

insert into tbl values
('A','D'),
('A','E'),
('A','F'),
('B','F'),
('B','E'),
('C','E'),
('C','D');

select
   hi,ho,
   row_number() over(partition by hi order by ho) as nr
from tbl;

PARTITION BY hi operates on non unique column, then on each partitioned column, you order on its unique column(ho), ORDER BY ho

Output:

HI  HO  NR
A   D   1
A   E   2
A   F   3
B   E   1
B   F   2
C   D   1
C   E   2

That data set makes more sense

Live test: http://www.sqlfiddle.com/#!3/d0b44/1

And this is similar to your query with same columns on both PARTITION BY and ORDER BY:

select
   hi,ho,
   row_number() over(partition by hi,ho order by hi,ho) as nr
from tbl;

And this is the ouput:

HI  HO  NR
A   D   1
A   E   1
A   F   1
B   E   1
B   F   1
C   D   1
C   E   1

See? no sense?

Live test: http://www.sqlfiddle.com/#!3/d0b44/3


Finally this might be the right query:

SELECT cdt.*,
     ROW_NUMBER ()
     OVER (PARTITION BY cdt.country_code, cdt.account -- removed: cdt.currency
           ORDER BY 
               -- removed: cdt.country_code, cdt.account, 
               cdt.currency) -- keep
        seq_no
FROM CUSTOMER_DETAILS cdt

How can I capture packets in Android?

It's probably worth mentioning that for http/https some people proxy their browser traffic through Burp/ZAP or another intercepting "attack proxy". A thread that covers options for this on Android devices can be found here: https://android.stackexchange.com/questions/32366/which-browser-does-support-proxies

How to save a BufferedImage as a File

As a one liner:

ImageIO.write(Scalr.resize(ImageIO.read(...), 150));

final keyword in method parameters

Java is only pass-by-value. (or better - pass-reference-by-value)

So the passed argument and the argument within the method are two different handlers pointing to the same object (value).

Therefore if you change the state of the object, it is reflected to every other variable that's referencing it. But if you re-assign a new object (value) to the argument, then other variables pointing to this object (value) do not get re-assigned.

minimum double value in C/C++

Are you looking for actual infinity or the minimal finite value? If the former, use

-numeric_limits<double>::infinity()

which only works if

numeric_limits<double>::has_infinity

Otherwise, you should use

numeric_limits<double>::lowest()

which was introduces in C++11.

If lowest() is not available, you can fall back to

-numeric_limits<double>::max()

which may differ from lowest() in principle, but normally doesn't in practice.

SELECT COUNT in LINQ to SQL C#

You should be able to do the count on the purch variable:

purch.Count();

e.g.

var purch = from purchase in myBlaContext.purchases
select purchase;

purch.Count();

Javascript ES6/ES5 find in array and change

My best approach is:

var item = {...}
var items = [{id:2}, {id:2}, {id:2}];

items[items.findIndex(el => el.id === item.id)] = item;

Reference for findIndex

And in case you don't want to replace with new object, but instead to copy the fields of item, you can use Object.assign:

Object.assign(items[items.findIndex(el => el.id === item.id)], item)

as an alternative with .map():

Object.assign(items, items.map(el => el.id === item.id? item : el))

Functional approach:

Don't modify the array, use a new one, so you don't generate side effects

const updatedItems = items.map(el => el.id === item.id ? item : el)

How to check if a string contains an element from a list in Python

This is a variant of the list comprehension answer given by @psun.

By switching the output value, you can actually extract the matching pattern from the list comprehension (something not possible with the any() approach by @Lauritz-v-Thaulow)

extensionsToCheck = ['.pdf', '.doc', '.xls']
url_string = 'http://.../foo.doc'

print [extension for extension in extensionsToCheck if(extension in url_string)]

['.doc']`

You can furthermore insert a regular expression if you want to collect additional information once the matched pattern is known (this could be useful when the list of allowed patterns is too long to write into a single regex pattern)

print [re.search(r'(\w+)'+extension, url_string).group(0) for extension in extensionsToCheck if(extension in url_string)]

['foo.doc']

HTML email in outlook table width issue - content is wider than the specified table width

I guess problem is in width attributes in table and td remove 'px' for example

<table border="0" cellpadding="0" cellspacing="0" width="580px" style="background-color: #0290ba;">

Should be

<table border="0" cellpadding="0" cellspacing="0" width="580" style="background-color: #0290ba;">

How to use a jQuery plugin inside Vue

import jquery within <script> tag in your vue file.

I think this is the easiest way.

For example,

<script>
import $ from "jquery";

export default {
    name: 'welcome',
    mounted: function() {
        window.setTimeout(function() {
            $('.logo').css('opacity', 0);   
        }, 1000);
    } 
}
</script>

How can I remove the last character of a string in python?

The easiest is

as @greggo pointed out

string="mystring";
string[:-1]

Bubble Sort Homework

The problem with the original algorithm is that if you had a lower number further in the list, it would not bring it to the correct sorted position. The program needs to go back the the beginning each time to ensure that the numbers sort all the way through.

I simplified the code and it will now work for any list of numbers regardless of the list and even if there are repeating numbers. Here's the code

mylist = [9, 8, 5, 4, 12, 1, 7, 5, 2]
print mylist

def bubble(badList):
    length = len(badList) - 1
    element = 0
    while element < length:
        if badList[element] > badList[element + 1]:
            hold = badList[element + 1]
            badList[element + 1] = badList[element]
            badList[element] = hold
            element = 0
            print badList
        else:
            element = element + 1

print bubble(mylist)

What is the regular expression to allow uppercase/lowercase (alphabetical characters), periods, spaces and dashes only?

Check out the basics of regular expressions in a tutorial. All it requires is two anchors and a repeated character class:

^[a-zA-Z ._-]*$

If you use the case-insensitive modifier, you can shorten this to

^[a-z ._-]*$

Note that the space is significant (it is just a character like any other).

Node.js/Express routing with get params

For Query parameters like domain.com/test?format=json&type=mini format, then you can easily receive it via - req.query.

app.get('/test', function(req, res){
  var format = req.query.format,
      type = req.query.type;
});

JavaScript: changing the value of onclick with or without jQuery

One gotcha with Jquery is that the click function do not acknowledge the hand coded onclick from the html.

So, you pretty much have to choose. Set up all your handlers in the init function or all of them in html.

The click event in JQuery is the click function $("myelt").click (function ....).

PHP DateTime __construct() Failed to parse time string (xxxxxxxx) at position x

change your code to this

$start_date = new DateTime( "@" . $dbResult->db_timestamp );

and it will work fine

W3WP.EXE using 100% CPU - where to start?

If you identify a page that takes time to load, use SharePoint's Developer Dashboard to see which component takes time.

multiprocessing: How do I share a dict among multiple processes?

In addition to @senderle's here, some might also be wondering how to use the functionality of multiprocessing.Pool.

The nice thing is that there is a .Pool() method to the manager instance that mimics all the familiar API of the top-level multiprocessing.

from itertools import repeat
import multiprocessing as mp
import os
import pprint

def f(d: dict) -> None:
    pid = os.getpid()
    d[pid] = "Hi, I was written by process %d" % pid

if __name__ == '__main__':
    with mp.Manager() as manager:
        d = manager.dict()
        with manager.Pool() as pool:
            pool.map(f, repeat(d, 10))
        # `d` is a DictProxy object that can be converted to dict
        pprint.pprint(dict(d))

Output:

$ python3 mul.py 
{22562: 'Hi, I was written by process 22562',
 22563: 'Hi, I was written by process 22563',
 22564: 'Hi, I was written by process 22564',
 22565: 'Hi, I was written by process 22565',
 22566: 'Hi, I was written by process 22566',
 22567: 'Hi, I was written by process 22567',
 22568: 'Hi, I was written by process 22568',
 22569: 'Hi, I was written by process 22569',
 22570: 'Hi, I was written by process 22570',
 22571: 'Hi, I was written by process 22571'}

This is a slightly different example where each process just logs its process ID to the global DictProxy object d.

How to POST form data with Spring RestTemplate?

Your url String needs variable markers for the map you pass to work, like:

String url = "https://app.example.com/hr/email?{email}";

Or you could explicitly code the query params into the String to begin with and not have to pass the map at all, like:

String url = "https://app.example.com/hr/[email protected]";

See also https://stackoverflow.com/a/47045624/1357094

json_encode(): Invalid UTF-8 sequence in argument

The problem is that this character is UTF8, but json_encode does not handle it correctly. To say more, there is a list of other characters (see Unicode characters list), that will trigger the same error, so stripping off this one (Å) will not correct an issue to the end.

What we have used is to convert these chars to html entities like this:

htmlentities( (string) $value, ENT_QUOTES, 'utf-8', FALSE);

HashMap - getting First Key value

Also a nice way of doing this :)

Map<Integer,JsonObject> requestOutput = getRequestOutput(client,post);
int statusCode = requestOutput.keySet().stream().findFirst().orElseThrow(() -> new RuntimeException("Empty"));

Concatenating strings in C, which method is more efficient?

Don't worry about efficiency: make your code readable and maintainable. I doubt the difference between these methods is going to matter in your program.

Prevent any form of page refresh using jQuery/Javascript

Back in the ole days of CGI we had many forms that would trigger various backend actions. Such as text notifications to groups, print jobs, farming of data, etc.

If the user was on a page that was saying "Please wait... Performing some HUGE job that could take some time.". They were more likely to hit REFRESH and this would be BAD!

WHY? Because it would trigger more slow jobs and eventually bog down the whole thing.

The solution? Allow them to do their form. When they submit their form... Start your job and then direct them to another page that tells them to wait.

Where the page in the middle actually held the form data that was needed to start the job. The WAIT page however contains a javascript history destroy. So they can RELOAD that wait page all they want and it will never trigger the original job to start in the background as that WAIT page only contains the form data needed for the WAIT itself.

Hope that makes sense.

The history destroy function also prevented them from clicking BACK and then refreshing as well.

It was very seamless and worked great for MANY MANY years until the non-profit was wound down.

Example: FORM ENTRY - Collect all their info and when submitted, this triggers your backend job.

RESPONSE from form entry - Returns HTML that performs a redirect to your static wait page and/or POST/GET to another form (the WAIT page).

WAIT PAGE - Only contains FORM data related to wait page as well as javascript to destroy the most recent history. Like (-1 OR -2) to only destroy the most recent pages, but still allows them to go back to their original FORM entry page.

Once they are at your WAIT page, they can click REFRESH as much as they want and it will never spawn the original FORM job on the backend. Instead, your WAIT page should embrace a META timed refresh itself so it can always check on the status of their job. When their job is completed, they are redirected away from the wait page to whereever you wish.

If they do manually REFRESH... They are simply adding one more check of their job status in there.

Hope that helps. Good luck.

How do you do a deep copy of an object in .NET?

I wrote a deep object copy extension method, based on recursive "MemberwiseClone". It is fast (three times faster than BinaryFormatter), and it works with any object. You don't need a default constructor or serializable attributes.

Source code:

using System.Collections.Generic;
using System.Reflection;
using System.ArrayExtensions;

namespace System
{
    public static class ObjectExtensions
    {
        private static readonly MethodInfo CloneMethod = typeof(Object).GetMethod("MemberwiseClone", BindingFlags.NonPublic | BindingFlags.Instance);

        public static bool IsPrimitive(this Type type)
        {
            if (type == typeof(String)) return true;
            return (type.IsValueType & type.IsPrimitive);
        }

        public static Object Copy(this Object originalObject)
        {
            return InternalCopy(originalObject, new Dictionary<Object, Object>(new ReferenceEqualityComparer()));
        }
        private static Object InternalCopy(Object originalObject, IDictionary<Object, Object> visited)
        {
            if (originalObject == null) return null;
            var typeToReflect = originalObject.GetType();
            if (IsPrimitive(typeToReflect)) return originalObject;
            if (visited.ContainsKey(originalObject)) return visited[originalObject];
            if (typeof(Delegate).IsAssignableFrom(typeToReflect)) return null;
            var cloneObject = CloneMethod.Invoke(originalObject, null);
            if (typeToReflect.IsArray)
            {
                var arrayType = typeToReflect.GetElementType();
                if (IsPrimitive(arrayType) == false)
                {
                    Array clonedArray = (Array)cloneObject;
                    clonedArray.ForEach((array, indices) => array.SetValue(InternalCopy(clonedArray.GetValue(indices), visited), indices));
                }

            }
            visited.Add(originalObject, cloneObject);
            CopyFields(originalObject, visited, cloneObject, typeToReflect);
            RecursiveCopyBaseTypePrivateFields(originalObject, visited, cloneObject, typeToReflect);
            return cloneObject;
        }

        private static void RecursiveCopyBaseTypePrivateFields(object originalObject, IDictionary<object, object> visited, object cloneObject, Type typeToReflect)
        {
            if (typeToReflect.BaseType != null)
            {
                RecursiveCopyBaseTypePrivateFields(originalObject, visited, cloneObject, typeToReflect.BaseType);
                CopyFields(originalObject, visited, cloneObject, typeToReflect.BaseType, BindingFlags.Instance | BindingFlags.NonPublic, info => info.IsPrivate);
            }
        }

        private static void CopyFields(object originalObject, IDictionary<object, object> visited, object cloneObject, Type typeToReflect, BindingFlags bindingFlags = BindingFlags.Instance | BindingFlags.NonPublic | BindingFlags.Public | BindingFlags.FlattenHierarchy, Func<FieldInfo, bool> filter = null)
        {
            foreach (FieldInfo fieldInfo in typeToReflect.GetFields(bindingFlags))
            {
                if (filter != null && filter(fieldInfo) == false) continue;
                if (IsPrimitive(fieldInfo.FieldType)) continue;
                var originalFieldValue = fieldInfo.GetValue(originalObject);
                var clonedFieldValue = InternalCopy(originalFieldValue, visited);
                fieldInfo.SetValue(cloneObject, clonedFieldValue);
            }
        }
        public static T Copy<T>(this T original)
        {
            return (T)Copy((Object)original);
        }
    }

    public class ReferenceEqualityComparer : EqualityComparer<Object>
    {
        public override bool Equals(object x, object y)
        {
            return ReferenceEquals(x, y);
        }
        public override int GetHashCode(object obj)
        {
            if (obj == null) return 0;
            return obj.GetHashCode();
        }
    }

    namespace ArrayExtensions
    {
        public static class ArrayExtensions
        {
            public static void ForEach(this Array array, Action<Array, int[]> action)
            {
                if (array.LongLength == 0) return;
                ArrayTraverse walker = new ArrayTraverse(array);
                do action(array, walker.Position);
                while (walker.Step());
            }
        }

        internal class ArrayTraverse
        {
            public int[] Position;
            private int[] maxLengths;

            public ArrayTraverse(Array array)
            {
                maxLengths = new int[array.Rank];
                for (int i = 0; i < array.Rank; ++i)
                {
                    maxLengths[i] = array.GetLength(i) - 1;
                }
                Position = new int[array.Rank];
            }

            public bool Step()
            {
                for (int i = 0; i < Position.Length; ++i)
                {
                    if (Position[i] < maxLengths[i])
                    {
                        Position[i]++;
                        for (int j = 0; j < i; j++)
                        {
                            Position[j] = 0;
                        }
                        return true;
                    }
                }
                return false;
            }
        }
    }

}

What is the best way to manage a user's session in React?

There is a React module called react-client-session that makes storing client side session data very easy. The git repo is here.

This is implemented in a similar way as the closure approach in my other answer, however it also supports persistence using 3 different persistence stores. The default store is memory(not persistent).

  1. Cookie
  2. localStorage
  3. sessionStorage

After installing, just set the desired store type where you mount the root component ...

import ReactSession from 'react-client-session';

ReactSession.setStoreType("localStorage");

... and set/get key value pairs from anywhere in your app:

import ReactSession from 'react-client-session';

ReactSession.set("username", "Bob");
ReactSession.get("username");  // Returns "Bob"

How to find the socket connection state in C?

TCP keepalive socket option (SO_KEEPALIVE) would help in this scenario and close server socket in case of connection loss.

How to count the number of occurrences of a character in an Oracle varchar value?

Here you go:

select length('123-345-566') - length(replace('123-345-566','-',null)) 
from dual;

Technically, if the string you want to check contains only the character you want to count, the above query will return NULL; the following query will give the correct answer in all cases:

select coalesce(length('123-345-566') - length(replace('123-345-566','-',null)), length('123-345-566'), 0) 
from dual;

The final 0 in coalesce catches the case where you're counting in an empty string (i.e. NULL, because length(NULL) = NULL in ORACLE).

SQL Server find and replace specific word in all rows of specific column

You can also export the database and then use a program like notepad++ to replace words and then inmport aigain.

How to implement a Boolean search with multiple columns in pandas

the query() method can do that very intuitively. Express your condition in a string to be evaluated like the following example :

df = df.query("columnNameA <= @x or columnNameB == @y")

with x and y are declared variables which you can refer to with @

Not receiving Google OAuth refresh token

This has caused me some confusion so I thought I'd share what I've come to learn the hard way:

When you request access using the access_type=offline and approval_prompt=force parameters you should receive both an access token and a refresh token. The access token expires soon after you receive it and you will need to refresh it.

You correctly made the request to get a new access token and received the response that has your new access token. I was also confused by the fact that I didn't get a new refresh token. However, this is how it is meant to be since you can use the same refresh token over and over again.

I think some of the other answers assume that you wanted to get yourself a new refresh token for some reason and sugggested that you re-authorize the user but in actual fact, you don't need to since the refresh token you have will work until revoked by the user.

How to properly make a http web GET request

Servers sometimes compress their responses to save on bandwidth, when this happens, you need to decompress the response before attempting to read it. Fortunately, the .NET framework can do this automatically, however, we have to turn the setting on.

Here's an example of how you could achieve that.

string html = string.Empty;
string url = @"https://api.stackexchange.com/2.2/answers?order=desc&sort=activity&site=stackoverflow";

HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
request.AutomaticDecompression = DecompressionMethods.GZip;

using (HttpWebResponse response = (HttpWebResponse)request.GetResponse())
using (Stream stream = response.GetResponseStream())
using (StreamReader reader = new StreamReader(stream))
{
    html = reader.ReadToEnd();
}

Console.WriteLine(html);

GET

public string Get(string uri)
{
    HttpWebRequest request = (HttpWebRequest)WebRequest.Create(uri);
    request.AutomaticDecompression = DecompressionMethods.GZip | DecompressionMethods.Deflate;

    using(HttpWebResponse response = (HttpWebResponse)request.GetResponse())
    using(Stream stream = response.GetResponseStream())
    using(StreamReader reader = new StreamReader(stream))
    {
        return reader.ReadToEnd();
    }
}

GET async

public async Task<string> GetAsync(string uri)
{
    HttpWebRequest request = (HttpWebRequest)WebRequest.Create(uri);
    request.AutomaticDecompression = DecompressionMethods.GZip | DecompressionMethods.Deflate;

    using(HttpWebResponse response = (HttpWebResponse)await request.GetResponseAsync())
    using(Stream stream = response.GetResponseStream())
    using(StreamReader reader = new StreamReader(stream))
    {
        return await reader.ReadToEndAsync();
    }
}

POST
Contains the parameter method in the event you wish to use other HTTP methods such as PUT, DELETE, ETC

public string Post(string uri, string data, string contentType, string method = "POST")
{
    byte[] dataBytes = Encoding.UTF8.GetBytes(data);

    HttpWebRequest request = (HttpWebRequest)WebRequest.Create(uri);
    request.AutomaticDecompression = DecompressionMethods.GZip | DecompressionMethods.Deflate;
    request.ContentLength = dataBytes.Length;
    request.ContentType = contentType;
    request.Method = method;

    using(Stream requestBody = request.GetRequestStream())
    {
        requestBody.Write(dataBytes, 0, dataBytes.Length);
    }

    using(HttpWebResponse response = (HttpWebResponse)request.GetResponse())
    using(Stream stream = response.GetResponseStream())
    using(StreamReader reader = new StreamReader(stream))
    {
        return reader.ReadToEnd();
    }
}

    

POST async
Contains the parameter method in the event you wish to use other HTTP methods such as PUT, DELETE, ETC

public async Task<string> PostAsync(string uri, string data, string contentType, string method = "POST")
{
    byte[] dataBytes = Encoding.UTF8.GetBytes(data);

    HttpWebRequest request = (HttpWebRequest)WebRequest.Create(uri);
    request.AutomaticDecompression = DecompressionMethods.GZip | DecompressionMethods.Deflate;
    request.ContentLength = dataBytes.Length;
    request.ContentType = contentType;
    request.Method = method;

    using(Stream requestBody = request.GetRequestStream())
    {
        await requestBody.WriteAsync(dataBytes, 0, dataBytes.Length);
    }

    using(HttpWebResponse response = (HttpWebResponse)await request.GetResponseAsync())
    using(Stream stream = response.GetResponseStream())
    using(StreamReader reader = new StreamReader(stream))
    {
        return await reader.ReadToEndAsync();
    }
}

How to detect the currently pressed key?

Most of these answers are either far too complicated or don't seem to work for me (e.g. System.Windows.Input doesn't seem to exist). Then I found some sample code which works fine: http://www.switchonthecode.com/tutorials/winforms-accessing-mouse-and-keyboard-state

In case the page disappears in the future I am posting the relevant source code below:

using System;
using System.Windows.Forms;
using System.Runtime.InteropServices;

namespace MouseKeyboardStateTest
{
  public abstract class Keyboard
  {
    [Flags]
    private enum KeyStates
    {
      None = 0,
      Down = 1,
      Toggled = 2
    }

    [DllImport("user32.dll", CharSet = CharSet.Auto, ExactSpelling = true)]
    private static extern short GetKeyState(int keyCode);

    private static KeyStates GetKeyState(Keys key)
    {
      KeyStates state = KeyStates.None;

      short retVal = GetKeyState((int)key);

      //If the high-order bit is 1, the key is down
      //otherwise, it is up.
      if ((retVal & 0x8000) == 0x8000)
        state |= KeyStates.Down;

      //If the low-order bit is 1, the key is toggled.
      if ((retVal & 1) == 1)
        state |= KeyStates.Toggled;

      return state;
    }

    public static bool IsKeyDown(Keys key)
    { 
      return KeyStates.Down == (GetKeyState(key) & KeyStates.Down);
    }

    public static bool IsKeyToggled(Keys key)
    { 
      return KeyStates.Toggled == (GetKeyState(key) & KeyStates.Toggled);
    }
  }
}

The representation of if-elseif-else in EL using JSF

You can use "ELSE IF" using conditional operator in expression language as below:

 <p:outputLabel value="#{transaction.status.equals('PNDNG')?'Pending':
                                     transaction.status.equals('RJCTD')?'Rejected':
                                     transaction.status.equals('CNFRMD')?'Confirmed':
                                     transaction.status.equals('PSTD')?'Posted':''}"/>

How to split elements of a list?

Something like:

>>> l = ['element1\t0238.94', 'element2\t2.3904', 'element3\t0139847']
>>> [i.split('\t', 1)[0] for i in l]
['element1', 'element2', 'element3']

Customizing Bootstrap CSS template

you can start with this tool, https://themestr.app/theme , seeing how it overwrites the scss variables, you would get an idea what variable impacts what. its the simplest way I think.

example scss genearation:

@import url(https://fonts.googleapis.com/css?family=Montserrat:200,300,400,700);
$font-family-base:Montserrat;
@import url(https://fonts.googleapis.com/css?family=Open+Sans:200,300,400,700);
$headings-font-family:Open Sans;

$enable-grid-classes:false;
$primary:#222222;
$secondary:#666666;
$success:#333333;
$danger:#434343;
$info:#515151;
$warning:#5f5f5f;
$light:#eceeec;
$dark:#111111;
@import "bootstrap";

Java Reflection: How to get the name of a variable?

All you need to do is make an array of fields and then set it to the class you want like shown below.

Field fld[] = (class name).class.getDeclaredFields();   
for(Field x : fld)
{System.out.println(x);}

For example if you did

Field fld[] = Integer.class.getDeclaredFields();
          for(Field x : fld)
          {System.out.println(x);}

you would get

public static final int java.lang.Integer.MIN_VALUE
public static final int java.lang.Integer.MAX_VALUE
public static final java.lang.Class java.lang.Integer.TYPE
static final char[] java.lang.Integer.digits
static final char[] java.lang.Integer.DigitTens
static final char[] java.lang.Integer.DigitOnes
static final int[] java.lang.Integer.sizeTable
private static java.lang.String java.lang.Integer.integerCacheHighPropValue
private final int java.lang.Integer.value
public static final int java.lang.Integer.SIZE
private static final long java.lang.Integer.serialVersionUID

jquery - is not a function error

It works on my case:

import * as JQuery from "jquery";
const $ = JQuery.default;

"Could not find the main class" error when running jar exported by Eclipse

Verify that you can start your application like that:

java -cp myjarfile.jar snake.Controller

I just read when I double click on it - this sounds like a configuration issue with your operating system. You're double-clicking the file on a windows explorer window? Try to run it from a console/terminal with the command

java -jar myjarfile.jar

Further Reading


The manifest has to end with a new line. Please check your file, a missing new line will cause trouble.

How can I properly use a PDO object for a parameterized SELECT query

A litle bit complete answer is here with all ready for use:

    $sql = "SELECT `username` FROM `users` WHERE `id` = :id";
    $q = $dbh->prepare($sql);
    $q->execute(array(':id' => "4"));
    $done= $q->fetch();

 echo $done[0];

Here $dbh is PDO db connecter, and based on id from table users we've get the username using fetch();

I hope this help someone, Enjoy!

Dynamically add properties to a existing object

Take a look at the ExpandoObject.

For example:

dynamic person = new ExpandoObject();
person.Name = "Mr bar";
person.Sex = "No Thanks";
person.Age = 123;

Additional reading here.

How can I create a "Please Wait, Loading..." animation using jQuery?

This would make the buttons disappear, then an animation of "loading" would appear in their place and finally just display a success message.

$(function(){
    $('#submit').click(function(){
        $('#submit').hide();
        $("#form .buttons").append('<img src="assets/img/loading.gif" alt="Loading..." id="loading" />');
        $.post("sendmail.php",
                {emailFrom: nameVal, subject: subjectVal, message: messageVal},
                function(data){
                    jQuery("#form").slideUp("normal", function() {                 
                        $("#form").before('<h1>Success</h1><p>Your email was sent.</p>');
                    });
                }
        );
    });
});

Replace non-numeric with empty string

Definitely regex:

string CleanPhone(string phone)
{
    Regex digitsOnly = new Regex(@"[^\d]");   
    return digitsOnly.Replace(phone, "");
}

or within a class to avoid re-creating the regex all the time:

private static Regex digitsOnly = new Regex(@"[^\d]");   

public static string CleanPhone(string phone)
{
    return digitsOnly.Replace(phone, "");
}

Depending on your real-world inputs, you may want some additional logic there to do things like strip out leading 1's (for long distance) or anything trailing an x or X (for extensions).

How do I change a TCP socket to be non-blocking?

fcntl() or ioctl() are used to set the properties for file streams. When you use this function to make a socket non-blocking, function like accept(), recv() and etc, which are blocking in nature will return error and errno would be set to EWOULDBLOCK. You can poll file descriptor sets to poll on sockets.

Can you get a Windows (AD) username in PHP?

try this code :

$user= shell_exec("echo %username%"); 
    echo "user : $user";

you get your windows(AD) username in php

Android Studio shortcuts like Eclipse

If you use Android Studio with Mac OS X these are some shortcuts:

- Compile java sources SHF+CMD+F9

- Build the project CMD+F9

- Run the current configuration CTR+R

- Run in debugger CTR+D

- Open project properties CMD++;

- Open Android Studio preferences CMD++,

- Find any command SHF+CMD+A

- Auto-format code OPT+CMD+L

- Delete line CMD+DELETE or CMD+Backspace

- Duplicate line/selection CMD+D

- Copy line CMD+C (with nothing selected)

- Select next occurance(s) CTR+G

Scope based selection

  • Select next higher scope Option+UP

  • Select next lower scope Option+DOWN

enter image description here

Navigating the code

- Open class CMD+O

- Open file SHF+CMD+O

- Navigate back to last position CMD+[

- Navigate forward to previous position CMD+]

- Switch to recently used files CRT+TAB

Intention Actions

  • If/Switch actions Option+RETURN

enter image description here

Create method CMD+N

or

enter image description here

Loop an array of ints

enter image description here

  • Generate Logs usin logd, loge, logi, logt, logm and logr

enter image description here

- Project quick fix ALT+ENTER

- Show docs for selected API F1

- Jump to source CMD+down-arrow

Most of them I found on this really good article and Android Studio Tips and Tricks

How do I use the lines of a file as arguments of a command?

If all you need to do is to turn file arguments.txt with contents

arg1
arg2
argN

into my_command arg1 arg2 argN then you can simply use xargs:

xargs -a arguments.txt my_command

You can put additional static arguments in the xargs call, like xargs -a arguments.txt my_command staticArg which will call my_command staticArg arg1 arg2 argN

Add php variable inside echo statement as href link address?

You can use one and more echo statement inside href

<a href="profile.php?usr=<?php echo $_SESSION['firstname']."&email=". $_SESSION['email']; ?> ">Link</a>

link : "/profile.php?usr=firstname&email=email"

Minimum and maximum value of z-index?

Z-Index only works for elements that have position: relative; or position: absolute; applied to them. If that's not the problem we'll need to see an example page to be more helpful.

EDIT: The good doctor has already put the fullest explanation but the quick version is that the minimum is 0 because it can't be a negative number and the maximum - well, you'll never really need to go above 10 for most designs.

How to read PDF files using Java?

with Apache PDFBox it goes like this:

PDDocument document = PDDocument.load(new File("test.pdf"));
if (!document.isEncrypted()) {
    PDFTextStripper stripper = new PDFTextStripper();
    String text = stripper.getText(document);
    System.out.println("Text:" + text);
}
document.close();

Get GPS location from the web browser

Observable

/*
  function geo_success(position) {
    do_something(position.coords.latitude, position.coords.longitude);
  }

  function geo_error() {
    alert("Sorry, no position available.");
  }

  var geo_options = {
    enableHighAccuracy: true,
    maximumAge        : 30000,
    timeout           : 27000
  };

  var wpid = navigator.geolocation.watchPosition(geo_success, geo_error, geo_options);
  */
  getLocation(): Observable<Position> {
    return Observable.create((observer) => {
      const watchID = navigator.geolocation.watchPosition((position: Position) => {
        observer.next(position);
      });
      return () => {
        navigator.geolocation.clearWatch(watchID);
      };
    });
  }

  ngOnDestroy() {
    this.sub.unsubscribe();
  }

How do I make case-insensitive queries on Mongodb?

To find case-insensitive literals string:

Using regex (recommended)

db.collection.find({
    name: {
        $regex: new RegExp('^' + name.replace(/[-\/\\^$*+?.()|[\]{}]/g, '\\$&') + '$', 'i')
    }
});

Using lower-case index (faster)

db.collection.find({
    name_lower: name.toLowerCase()
});

Regular expressions are slower than literal string matching. However, an additional lowercase field will increase your code complexity. When in doubt, use regular expressions. I would suggest to only use an explicitly lower-case field if it can replace your field, that is, you don't care about the case in the first place.

Note that you will need to escape the name prior to regex. If you want user-input wildcards, prefer appending .replace(/%/g, '.*') after escaping so that you can match "a%" to find all names starting with 'a'.

Stop all active ajax requests in jQuery

I had some problems with andy's code, but it gave me some great ideas. First problem was that we should pop off any jqXHR objects that successfully complete. I also had to modify the abortAll function. Here is my final working code:

$.xhrPool = [];
$.xhrPool.abortAll = function() {
            $(this).each(function(idx, jqXHR) {
                        jqXHR.abort();
                        });
};
$.ajaxSetup({
    beforeSend: function(jqXHR) {
            $.xhrPool.push(jqXHR);
            }
});
$(document).ajaxComplete(function() {
            $.xhrPool.pop();
            });

I didn't like the ajaxComplete() way of doing things. No matter how I tried to configure .ajaxSetup it did not work.

Android Pop-up message

sample code show custom dialog in kotlin:

fun showDlgFurtherDetails(context: Context,title: String?, details: String?) {

    val dialog = Dialog(context)
    dialog.requestWindowFeature(Window.FEATURE_NO_TITLE)
    dialog.setCancelable(false)
    dialog.setContentView(R.layout.dlg_further_details)
    dialog.window?.setBackgroundDrawable(ColorDrawable(Color.TRANSPARENT))
    val lblService = dialog.findViewById(R.id.lblService) as TextView
    val lblDetails = dialog.findViewById(R.id.lblDetails) as TextView
    val imgCloseDlg = dialog.findViewById(R.id.imgCloseDlg) as ImageView

    lblService.text = title
    lblDetails.text = details
    lblDetails.movementMethod = ScrollingMovementMethod()
    lblDetails.isScrollbarFadingEnabled = false
    imgCloseDlg.setOnClickListener {
        dialog.dismiss()
    }
    dialog.show()
}

UTF-8, UTF-16, and UTF-32

UTF-8 has an advantage in the case where ASCII characters represent the majority of characters in a block of text, because UTF-8 encodes these into 8 bits (like ASCII). It is also advantageous in that a UTF-8 file containing only ASCII characters has the same encoding as an ASCII file.

UTF-16 is better where ASCII is not predominant, since it uses 2 bytes per character, primarily. UTF-8 will start to use 3 or more bytes for the higher order characters where UTF-16 remains at just 2 bytes for most characters.

UTF-32 will cover all possible characters in 4 bytes. This makes it pretty bloated. I can't think of any advantage to using it.

Dynamically Changing log4j log level

With log4j 1.x I find the best way is to use a DOMConfigurator to submit one of a predefined set of XML log configurations (say, one for normal use and one for debugging).

Making use of these can be done with something like this:

  public static void reconfigurePredefined(String newLoggerConfigName) {
    String name = newLoggerConfigName.toLowerCase();
    if ("default".equals(name)) {
      name = "log4j.xml";
    } else {
      name = "log4j-" + name + ".xml";
    }

    if (Log4jReconfigurator.class.getResource("/" + name) != null) {
      String logConfigPath = Log4jReconfigurator.class.getResource("/" + name).getPath();
      logger.warn("Using log4j configuration: " + logConfigPath);
      try (InputStream defaultIs = Log4jReconfigurator.class.getResourceAsStream("/" + name)) {
        new DOMConfigurator().doConfigure(defaultIs, LogManager.getLoggerRepository());
      } catch (IOException e) {
        logger.error("Failed to reconfigure log4j configuration, could not find file " + logConfigPath + " on the classpath", e);
      } catch (FactoryConfigurationError e) {
        logger.error("Failed to reconfigure log4j configuration, could not load file " + logConfigPath, e);
      }
    } else {
      logger.error("Could not find log4j configuration file " + name + ".xml on classpath");
    }
  }

Just call this with the appropriate config name, and make sure that you put the templates on the classpath.

Under what circumstances can I call findViewById with an Options Menu / Action Bar item?

I am trying to obtain a handle on one of the views in the Action Bar

I will assume that you mean something established via android:actionLayout in your <item> element of your <menu> resource.

I have tried calling findViewById(R.id.menu_item)

To retrieve the View associated with your android:actionLayout, call findItem() on the Menu to retrieve the MenuItem, then call getActionView() on the MenuItem. This can be done any time after you have inflated the menu resource.

How to send data to COM PORT using JAVA?

The Java Communications API (also known as javax.comm) provides applications access to RS-232 hardware (serial ports): http://www.oracle.com/technetwork/java/index-jsp-141752.html

How to resolve ORA 00936 Missing Expression Error?

This answer is not the answer for the above mentioned question but it is related to same topic and might be useful for people searching for same error.

I faced the same error when I executed below mentioned query.

select OR.* from ORDER_REL_STAT OR

problem with above query was OR is keyword so it was expecting other values when I replaced with some other alias it worked fine.

How can I declare a Boolean parameter in SQL statement?

The same way you declare any other variable, just use the bit type:

DECLARE @MyVar bit
Set @MyVar = 1  /* True */
Set @MyVar = 0  /* False */

SELECT * FROM [MyTable] WHERE MyBitColumn = @MyVar

Convert a String to Modified Camel Case in Java or Title Case as is otherwise called

From commons-lang3

org.apache.commons.lang3.text.WordUtils.capitalizeFully(String str)

How to completely remove borders from HTML table

In a bootstrap environment none of the top answers helped, but applying the following removed all borders:

.noBorder {
    border:none !important;
}

Applied as:

<td class="noBorder">

Scale an equation to fit exact page width

I just had the situation that I wanted this only for lines exceeding \linewidth, that is: Squeezing long lines slightly. Since it took me hours to figure this out, I would like to add it here.

I want to emphasize that scaling fonts in LaTeX is a deadly sin! In nearly every situation, there is a better way (e.g. multline of the mathtools package). So use it conscious.

In this particular case, I had no influence on the code base apart the preamble and some lines slightly overshooting the page border when I compiled it as an eBook-scaled pdf.

\usepackage{environ}         % provides \BODY
\usepackage{etoolbox}        % provides \ifdimcomp
\usepackage{graphicx}        % provides \resizebox

\newlength{\myl}
\let\origequation=\equation
\let\origendequation=\endequation

\RenewEnviron{equation}{
  \settowidth{\myl}{$\BODY$}                       % calculate width and save as \myl
  \origequation
  \ifdimcomp{\the\linewidth}{>}{\the\myl}
  {\ensuremath{\BODY}}                             % True
  {\resizebox{\linewidth}{!}{\ensuremath{\BODY}}}  % False
  \origendequation
}

Before before After after

How to unzip files programmatically in Android?

Password Protected Zip File

if you want to compress files with password you can take a look at this library that can zip files with password easily:

Zip:

ZipArchive zipArchive = new ZipArchive();
zipArchive.zip(targetPath,destinationPath,password);

Unzip:

ZipArchive zipArchive = new ZipArchive();
zipArchive.unzip(targetPath,destinationPath,password);

Rar:

RarArchive rarArchive = new RarArchive();
rarArchive.extractArchive(file archive, file destination);

The documentation of this library is good enough, I just added a few examples from there. It's totally free and wrote specially for android.

fork() and wait() with two child processes

It looks to me as though the basic problem is that you have one wait() call rather than a loop that waits until there are no more children. You also only wait if the last fork() is successful rather than if at least one fork() is successful.

You should only use _exit() if you don't want normal cleanup operations - such as flushing open file streams including stdout. There are occasions to use _exit(); this is not one of them. (In this example, you could also, of course, simply have the children return instead of calling exit() directly because returning from main() is equivalent to exiting with the returned status. However, most often you would be doing the forking and so on in a function other than main(), and then exit() is often appropriate.)


Hacked, simplified version of your code that gives the diagnostics I'd want. Note that your for loop skipped the first element of the array (mine doesn't).

#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <sys/wait.h>

int main(void)
{
    pid_t child_pid, wpid;
    int status = 0;
    int i;
    int a[3] = {1, 2, 1};

    printf("parent_pid = %d\n", getpid());
    for (i = 0; i < 3; i++)
    {
        printf("i = %d\n", i);
        if ((child_pid = fork()) == 0)
        {
            printf("In child process (pid = %d)\n", getpid());
            if (a[i] < 2)
            {
                printf("Should be accept\n");
                exit(1);
            }
            else
            {
                printf("Should be reject\n");
                exit(0);
            }
            /*NOTREACHED*/
        }
    }

    while ((wpid = wait(&status)) > 0)
    {
        printf("Exit status of %d was %d (%s)\n", (int)wpid, status,
               (status > 0) ? "accept" : "reject");
    }
    return 0;
}

Example output (MacOS X 10.6.3):

parent_pid = 15820
i = 0
i = 1
In child process (pid = 15821)
Should be accept
i = 2
In child process (pid = 15822)
Should be reject
In child process (pid = 15823)
Should be accept
Exit status of 15823 was 256 (accept)
Exit status of 15822 was 0 (reject)
Exit status of 15821 was 256 (accept)

Android - How to achieve setOnClickListener in Kotlin?

Add clickListener on button like this

    btUpdate.setOnClickListener(onclickListener)

add this code in your activity

 val onclickListener: View.OnClickListener = View.OnClickListener { view ->
        when (view.id) {
            R.id.btUpdate -> updateData()


        }
    }

How to properly import a selfsigned certificate into Java keystore that is available to all Java applications by default?

Might want to try

keytool -import -trustcacerts -noprompt -keystore <full path to cacerts> -storepass changeit -alias $REMHOST -file $REMHOST.pem

i honestly have no idea where it puts your certificate if you just write cacerts just give it a full path

pip issue installing almost any library

I found it sufficient to specify the pypi host as trusted. Example:

pip install --trusted-host pypi.python.org pytest-xdist
pip install --trusted-host pypi.python.org --upgrade pip

This solved the following error:

  Could not fetch URL https://pypi.python.org/simple/pytest-cov/: There was a problem confirming the ssl certificate: [SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed (_ssl.c:600) - skipping
  Could not find a version that satisfies the requirement pytest-cov (from versions: )
No matching distribution found for pytest-cov

Update April 2018: To anyone getting the TLSV1_ALERT_PROTOCOL_VERSION error: it has nothing to do with trusted-host/verification issue of the OP or this answer. Rather the TLSV1 error is because your interpreter does not support TLS v1.2, you must upgrade your interpreter. See for example https://news.ycombinator.com/item?id=13539034, http://pyfound.blogspot.ca/2017/01/time-to-upgrade-your-python-tls-v12.html and https://bugs.python.org/issue17128.

Update Feb 2019: For some it may be sufficient to upgrade pip. If the above error prevents you from doing this, use get-pip.py. E.g. on Linux,

curl https://bootstrap.pypa.io/get-pip.py
sudo python get-pip.py

More details at https://pip.pypa.io/en/stable/installing/.

Apache and IIS side by side (both listening to port 80) on windows2003

You need at least mod_proxy and mod_proxy_http which both are part of the distribution (yet not everytime built automatically). Then you can look here: http://httpd.apache.org/docs/2.2/mod/mod_proxy.html

Simplest config in a virtualhost context is:

ProxyPass         /winapp http://127.0.0.1:8080/somedir/

ProxyPassReverse  /winapp http://127.0.0.1:8080/somedir/

(Depending on your webapp, the actual config might become more sophisticated. ) That transparently redirects every request on the path winapp/ to the windows server and transfers the resulting output back to the client.

Attention: Take care of the links in the delivered pages: they aren't rewritten, so you can save yourself lotsa hassle if you generally use relative links in your app, like

<a href=../pics/mypic.jpg">

instead of the usual integration nightmare of every link being absolute:

<a href="http://myinternalhostname/somedir/crappydesign.jpg">

THE LATTER IS BAD ALMOST EVERY SINGLE TIME!

For rewriting links in pages there's mod_proxy_html (not to confuse with mod_proxy_http!) but that's another story and a cruel one as well.

IntelliJ cannot find any declarations

enter image description here

Importing my project (which had 3 different modules in it) - as File -> Module From Existing Sources fixed it for me.

setTimeout in for-loop does not print consecutive values

ANSWER?

I'm using it for an animation for adding items to a cart - a cart icon floats to the cart area from the product "add" button, when clicked:

function addCartItem(opts) {
    for (var i=0; i<opts.qty; i++) {
        setTimeout(function() {
            console.log('ADDED ONE!');
        }, 1000*i);
    }
};

NOTE the duration is in unit times n epocs.

So starting at the the click moment, the animations start epoc (of EACH animation) is the product of each one-second-unit multiplied by the number of items.

epoc: https://en.wikipedia.org/wiki/Epoch_(reference_date)

Hope this helps!

Passing Parameters JavaFX FXML

javafx.scene.Node class has a pair of methods setUserData(Object) and Object getUserData()

Which you could use to add your info to the Node.

So, you can call page.setUserData(info);

And controller can check, if info is set. Also, you could use ObjectProperty for back-forward data transfering, if needed.

Observe a documentation here: http://docs.oracle.com/javafx/2/api/javafx/fxml/doc-files/introduction_to_fxml.html Before the phrase "In the first version, the handleButtonAction() is tagged with @FXML to allow markup defined in the controller's document to invoke it. In the second example, the button field is annotated to allow the loader to set its value. The initialize() method is similarly annotated."

So, you need to associate a controller with a node, and set a user data to the node.

What is a non-capturing group in regular expressions?

Its extremely simple, We can understand with simple date example, suppose if the date is mentioned as 1st January 2019 or 2nd May 2019 or any other date and we simply want to convert it to dd/mm/yyyy format we would not need the month's name which is January or February for that matter, so in order to capture the numeric part, but not the (optional) suffix you can use a non-capturing group.

so the regular expression would be,

([0-9]+)(?:January|February)?

Its as simple as that.

HTTPS using Jersey Client

Waking up a dead question here but the answers provided will not work with jdk 7 (I read somewhere that a bug is open for this for Oracle Engineers but not fixed yet). Along with the link that @Ryan provided, you will have to also add :

System.setProperty("jsse.enableSNIExtension", "false");

(Courtesy to many stackoverflow answers combined together to figure this out)

The complete code will look as follows which worked for me (without setting the system property the Client Config did not work for me):

import java.security.SecureRandom;
import java.security.cert.CertificateException;
import java.security.cert.X509Certificate;

import javax.net.ssl.HostnameVerifier;
import javax.net.ssl.HttpsURLConnection;
import javax.net.ssl.SSLContext;
import javax.net.ssl.SSLSession;
import javax.net.ssl.TrustManager;
import javax.net.ssl.X509TrustManager;

import com.sun.jersey.api.client.Client;
import com.sun.jersey.api.client.config.ClientConfig;
import com.sun.jersey.api.client.config.DefaultClientConfig;
import com.sun.jersey.client.urlconnection.HTTPSProperties;
public class ClientHelper
{
    public static ClientConfig configureClient()
    {
        System.setProperty("jsse.enableSNIExtension", "false");
        TrustManager[] certs = new TrustManager[]
        {
            new X509TrustManager()
            {
                @Override
                public X509Certificate[] getAcceptedIssuers()
                {
                    return null;
                }

                @Override
                public void checkServerTrusted(X509Certificate[] chain, String authType)
                        throws CertificateException
                {
                }

                @Override
                public void checkClientTrusted(X509Certificate[] chain, String authType)
                        throws CertificateException
                {
                }
            }
        };
        SSLContext ctx = null;
        try
        {
            ctx = SSLContext.getInstance("SSL");
            ctx.init(null, certs, new SecureRandom());
        }
        catch (java.security.GeneralSecurityException ex)
        {
        }
        HttpsURLConnection.setDefaultSSLSocketFactory(ctx.getSocketFactory());
        ClientConfig config = new DefaultClientConfig();
        try
        {
            config.getProperties().put(HTTPSProperties.PROPERTY_HTTPS_PROPERTIES, new HTTPSProperties(
                    new HostnameVerifier()
            {
                @Override
                public boolean verify(String hostname, SSLSession session)
                {
                    return true;
                }
            },
                    ctx));
        }
        catch (Exception e)
        {
        }
        return config;
    }

    public static Client createClient()
    {
        return Client.create(ClientHelper.configureClient());
    }

How to get resources directory path programmatically

import org.springframework.core.io.ClassPathResource;

...

File folder = new ClassPathResource("sql").getFile();
File[] listOfFiles = folder.listFiles();

It is worth noting that this will limit your deployment options, ClassPathResource.getFile() only works if the container has exploded (unzipped) your war file.

Determine a user's timezone

JavaScript:

function maketimus(timestampz)
{
    var linktime = new Date(timestampz * 1000);
    var linkday = linktime.getDate();
    var freakingmonths = new Array();

    freakingmonths[0]  = "jan";
    freakingmonths[1]  = "feb";
    freakingmonths[2]  = "mar";
    freakingmonths[3]  = "apr";
    freakingmonths[4]  = "may";
    freakingmonths[5]  = "jun";
    freakingmonths[6]  = "jul";
    freakingmonths[7]  = "aug";
    freakingmonths[8]  = "sep";
    freakingmonths[9]  = "oct";
    freakingmonths[10] = "nov";
    freakingmonths[11] = "dec";

    var linkmonthnum = linktime.getMonth();
    var linkmonth = freakingmonths[linkmonthnum];
    var linkyear = linktime.getFullYear();
    var linkhour = linktime.getHours();
    var linkminute = linktime.getMinutes();

    if (linkminute < 10)
    {
        linkminute = "0" + linkminute;
    }

    var fomratedtime = linkday + linkmonth + linkyear + " " +
                       linkhour + ":" + linkminute + "h";
    return fomratedtime;
}

Simply provide your times in Unix timestamp format to this function; JavaScript already knows the timezone of the user.

Like this:

PHP:

echo '<script type="text/javascript">
var eltimio = maketimus('.$unix_timestamp_ofshiz.');
document.write(eltimio);
</script><noscript>pls enable javascript</noscript>';

This will always show the times correctly based on the timezone the person has set on his/her computer clock. There is no need to ask anything to anyone and save it into places, thank god!

How to normalize a signal to zero mean and unit variance?

if your signal is in the matrix X, you make it zero-mean by removing the average:

X=X-mean(X(:));

and unit variance by dividing by the standard deviation:

X=X/std(X(:));

Squaring all elements in a list

import numpy as np
a = [2 ,3, 4]
np.square(a)

What is difference between functional and imperative programming languages?

Most modern languages are in varying degree both imperative and functional but to better understand functional programming, it will be best to take an example of pure functional language like Haskell in contrast of imperative code in not so functional language like java/C#. I believe it is always easy to explain by example, so below is one.

Functional programming: calculate factorial of n i.e n! i.e n x (n-1) x (n-2) x ...x 2 X 1

-- | Haskell comment goes like
-- | below 2 lines is code to calculate factorial and 3rd is it's execution  

factorial 0 = 1
factorial n = n * factorial (n - 1)
factorial 3

-- | for brevity let's call factorial as f; And x => y shows order execution left to right
-- | above executes as := f(3) as 3 x f(2) => f(2) as 2 x f(1) => f(1) as 1 x f(0) => f(0) as 1  
-- | 3 x (2 x (1 x (1)) = 6

Notice that Haskel allows function overloading to the level of argument value. Now below is example of imperative code in increasing degree of imperativeness:

//somewhat functional way
function factorial(n) {
  if(n < 1) {
     return 1;
  }
  return n * factorial(n-1);   
}
factorial(3);

//somewhat more imperative way
function imperativeFactor(n) {
  int f = 1;
  for(int i = 1; i <= n; i++) {
     f = f * i;
  }
  return f;
}

This read can be a good reference to understand that how imperative code focus more on how part, state of machine (i in for loop), order of execution, flow control.

The later example can be seen as java/C# lang code roughly and first part as limitation of the language itself in contrast of Haskell to overload the function by value (zero) and hence can be said it is not purist functional language, on the other hand you can say it support functional prog. to some extent.

Disclosure: none of the above code is tested/executed but hopefully should be good enough to convey the concept; also I would appreciate comments for any such correction :)

filename and line number of Python script

Filename:

__file__
# or
sys.argv[0]

Line:

inspect.currentframe().f_lineno

(not inspect.currentframe().f_back.f_lineno as mentioned above)

ASP.NET 2.0 - How to use app_offline.htm

I ran into an issue very similar to the original question that took me a little while to resolve.

Just incase anyone else is working on an MVC application and finds their way into this thread, make sure that you have a wildcard mapping to the appropriate .Net aspnet_isapi.dll defined. As soon as I did this, my app_offline.htm started behaving as expected.


IIS 6 Configuration Steps

On IIS Application Properties, select virtual Directory tab.

Under Application Settings, click the Configuration button.

Under Wildcard application maps, click the Insert button.

Enter C:\WINDOWS\Microsoft.NET\Framework64\v4.0.30319\aspnet_isapi.dll, click OK.

ModuleNotFoundError: What does it mean __main__ is not a package?

Just use the name of the main folder which the .py file is in.

from problem_set_02.p_02_paying_debt_off_in_a_year import compute_balance_after

Convert DateTime in C# to yyyy-MM-dd format and Store it to MySql DateTime Field

We can use the below its very simple.

Date.ToString("yyyy-MM-dd");

How to POST URL in data of a curl request

Perhaps you don't have to include the single quotes:

curl --request POST 'http://localhost/Service' --data "path=/xyz/pqr/test/&fileName=1.doc"

Update: Reading curl's manual, you could actually separate both fields with two --data:

curl --request POST 'http://localhost/Service' --data "path=/xyz/pqr/test/" --data "fileName=1.doc"

You could also try --data-binary:

curl --request POST 'http://localhost/Service' --data-binary "path=/xyz/pqr/test/" --data-binary "fileName=1.doc"

And --data-urlencode:

curl --request POST 'http://localhost/Service' --data-urlencode "path=/xyz/pqr/test/" --data-urlencode "fileName=1.doc"

Matplotlib-Animation "No MovieWriters Available"

I know this question is about Linux, but in case someone stumbles on this problem on Mac like I did here is the solution for that. I had the exact same problem on Mac because ffmpeg is not installed by default apparently, and so I could solve it using:

brew install yasm
brew install ffmpeg

Where and why do I have to put the "template" and "typename" keywords?

I am placing JLBorges's excellent response to a similar question verbatim from cplusplus.com, as it is the most succinct explanation I've read on the subject.

In a template that we write, there are two kinds of names that could be used - dependant names and non- dependant names. A dependant name is a name that depends on a template parameter; a non-dependant name has the same meaning irrespective of what the template parameters are.

For example:

template< typename T > void foo( T& x, std::string str, int count )
{
    // these names are looked up during the second phase
    // when foo is instantiated and the type T is known
    x.size(); // dependant name (non-type)
    T::instance_count ; // dependant name (non-type)
    typename T::iterator i ; // dependant name (type)
      
    // during the first phase, 
    // T::instance_count is treated as a non-type (this is the default)
    // the typename keyword specifies that T::iterator is to be treated as a type.

    // these names are looked up during the first phase
    std::string::size_type s ; // non-dependant name (type)
    std::string::npos ; // non-dependant name (non-type)
    str.empty() ; // non-dependant name (non-type)
    count ; // non-dependant name (non-type)
}

What a dependant name refers to could be something different for each different instantiation of the template. As a consequence, C++ templates are subject to "two-phase name lookup". When a template is initially parsed (before any instantiation takes place) the compiler looks up the non-dependent names. When a particular instantiation of the template takes place, the template parameters are known by then, and the compiler looks up dependent names.

During the first phase, the parser needs to know if a dependant name is the name of a type or the name of a non-type. By default, a dependant name is assumed to be the name of a non-type. The typename keyword before a dependant name specifies that it is the name of a type.


Summary

Use the keyword typename only in template declarations and definitions provided you have a qualified name that refers to a type and depends on a template parameter.

Cannot implicitly convert type 'int?' to 'int'.

this is because the return type of your method is int and OrdersPerHour is int? (nullable) , you can solve this by returning its value like below:

return OrdersPerHour.Value

also check if its not null to avoid exception like as below:

if(OrdersPerHour != null)
{

    return OrdersPerHour.Value;

}
else
{

  return 0; // depends on your choice

}

but in this case you will have to return some other value in the else part or after the if part otherwise compiler will flag an error that not all paths of code return value.

find -mtime files older than 1 hour

What about -mmin?

find /var/www/html/audio -daystart -maxdepth 1 -mmin +59 -type f -name "*.mp3" \
    -exec rm -f {} \;

From man find:

-mmin n
        File's data was last modified n minutes ago.

Also, make sure to test this first!

... -exec echo rm -f '{}' \;
          ^^^^ Add the 'echo' so you just see the commands that are going to get
               run instead of actual trying them first.

RecyclerView: Inconsistency detected. Invalid item position

I had a (possibly) related issue - entering a new instance of an activity with a RecyclerView, but with a smaller adapter was triggering this crash for me.

RecyclerView.dispatchLayout() can try to pull items from the scrap before calling mRecycler.clearOldPositions(). The consequence being is that it was pulling items from the common pool that had positions higher than the adapter size.

Fortunately, it only does this if PredictiveAnimations are enabled, so my solution was to subclass GridLayoutManager (LinearLayoutManager has the same problem and 'fix'), and override supportsPredictiveItemAnimations() to return false :

/**
 * No Predictive Animations GridLayoutManager
 */
private static class NpaGridLayoutManager extends GridLayoutManager {
    /**
     * Disable predictive animations. There is a bug in RecyclerView which causes views that
     * are being reloaded to pull invalid ViewHolders from the internal recycler stack if the
     * adapter size has decreased since the ViewHolder was recycled.
     */
    @Override
    public boolean supportsPredictiveItemAnimations() {
        return false;
    }

    public NpaGridLayoutManager(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) {
        super(context, attrs, defStyleAttr, defStyleRes);
    }

    public NpaGridLayoutManager(Context context, int spanCount) {
        super(context, spanCount);
    }

    public NpaGridLayoutManager(Context context, int spanCount, int orientation, boolean reverseLayout) {
        super(context, spanCount, orientation, reverseLayout);
    }
}

How to measure time taken by a function to execute

The best way would be to use the performance hooks module. Although unstable, you can mark specific areas of your code and measure the duration between marked areas.

const { performance, PerformanceObserver } = require('perf_hooks');

const measures = []

const obs = new PerformanceObserver(list => measures.push(...list.getEntries()));
obs.observe({ entryTypes: ['measure'] });
const getEntriesByType = cb => cb(measures);

const doSomething = val => {
  performance.mark('beginning of the process');

  val *= 2;

  performance.mark('after multiplication');

  performance.measure('time taken', 'beginning of the process', 'after multiplication');

  getEntriesByType(entries => {
    entries.forEach(entry => console.log(entry));
  })

  return val;
}

doSomething(4);

Try here

What is the difference between Task.Run() and Task.Factory.StartNew()

According to this post by Stephen Cleary, Task.Factory.StartNew() is dangerous:

I see a lot of code on blogs and in SO questions that use Task.Factory.StartNew to spin up work on a background thread. Stephen Toub has an excellent blog article that explains why Task.Run is better than Task.Factory.StartNew, but I think a lot of people just haven’t read it (or don’t understand it). So, I’ve taken the same arguments, added some more forceful language, and we’ll see how this goes. :) StartNew does offer many more options than Task.Run, but it is quite dangerous, as we’ll see. You should prefer Task.Run over Task.Factory.StartNew in async code.

Here are the actual reasons:

  1. Does not understand async delegates. This is actually the same as point 1 in the reasons why you would want to use StartNew. The problem is that when you pass an async delegate to StartNew, it’s natural to assume that the returned task represents that delegate. However, since StartNew does not understand async delegates, what that task actually represents is just the beginning of that delegate. This is one of the first pitfalls that coders encounter when using StartNew in async code.
  2. Confusing default scheduler. OK, trick question time: in the code below, what thread does the method “A” run on?
Task.Factory.StartNew(A);

private static void A() { }

Well, you know it’s a trick question, eh? If you answered “a thread pool thread”, I’m sorry, but that’s not correct. “A” will run on whatever TaskScheduler is currently executing!

So that means it could potentially run on the UI thread if an operation completes and it marshals back to the UI thread due to a continuation as Stephen Cleary explains more fully in his post.

In my case, I was trying to run tasks in the background when loading a datagrid for a view while also displaying a busy animation. The busy animation didn't display when using Task.Factory.StartNew() but the animation displayed properly when I switched to Task.Run().

For details, please see https://blog.stephencleary.com/2013/08/startnew-is-dangerous.html

swift UITableView set rowHeight

As pointed out in comments, you cannot call cellForRowAtIndexPath inside heightForRowAtIndexPath.

What you can do is creating a template cell used to populate with your data and then compute its height. This cell doesn't participate to the table rendering, and it can be reused to calculate the height of each table cell.

Briefly, it consists of configuring the template cell with the data you want to display, make it resize accordingly to the content, and then read its height.

I have taken this code from a project I am working on - unfortunately it's in Objective C, I don't think you will have problems translating to swift

- (CGFloat) tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath {
    static PostCommentCell *sizingCell = nil;
    static dispatch_once_t onceToken;
    dispatch_once(&onceToken, ^{
        sizingCell = [self.tblComments dequeueReusableCellWithIdentifier:POST_COMMENT_CELL_IDENTIFIER];
    });

    sizingCell.comment = self.comments[indexPath.row];
    [sizingCell setNeedsLayout];
    [sizingCell layoutIfNeeded];

    CGSize size = [sizingCell.contentView systemLayoutSizeFittingSize:UILayoutFittingCompressedSize];
    return size.height;
}

Insert/Update Many to Many Entity Framework . How do I do it?

In terms of entities (or objects) you have a Class object which has a collection of Students and a Student object that has a collection of Classes. Since your StudentClass table only contains the Ids and no extra information, EF does not generate an entity for the joining table. That is the correct behaviour and that's what you expect.

Now, when doing inserts or updates, try to think in terms of objects. E.g. if you want to insert a class with two students, create the Class object, the Student objects, add the students to the class Students collection add the Class object to the context and call SaveChanges:

using (var context = new YourContext())
{
    var mathClass = new Class { Name = "Math" };
    mathClass.Students.Add(new Student { Name = "Alice" });
    mathClass.Students.Add(new Student { Name = "Bob" });

    context.AddToClasses(mathClass);
    context.SaveChanges();
}

This will create an entry in the Class table, two entries in the Student table and two entries in the StudentClass table linking them together.

You basically do the same for updates. Just fetch the data, modify the graph by adding and removing objects from collections, call SaveChanges. Check this similar question for details.

Edit:

According to your comment, you need to insert a new Class and add two existing Students to it:

using (var context = new YourContext())
{
    var mathClass= new Class { Name = "Math" };
    Student student1 = context.Students.FirstOrDefault(s => s.Name == "Alice");
    Student student2 = context.Students.FirstOrDefault(s => s.Name == "Bob");
    mathClass.Students.Add(student1);
    mathClass.Students.Add(student2);

    context.AddToClasses(mathClass);
    context.SaveChanges();
}

Since both students are already in the database, they won't be inserted, but since they are now in the Students collection of the Class, two entries will be inserted into the StudentClass table.

Python group by

result = []
# Make a set of your "types":
input_set = set([tpl[1] for tpl in input])
>>> set(['ETH', 'KAT', 'NOT'])
# Iterate over the input_set
for type_ in input_set:
    # a dict to gather things:
    D = {}
    # filter all tuples from your input with the same type as type_
    tuples = filter(lambda tpl: tpl[1] == type_, input)
    # write them in the D:
    D["type"] = type_
    D["itmes"] = [tpl[0] for tpl in tuples]
    # append D to results:
    result.append(D)

result
>>> [{'itmes': ['9085267', '11788544'], 'type': 'NOT'}, {'itmes': ['5238761', '5349618', '962142', '7795297', '7341464', '5594916', '1550003'], 'type': 'ETH'}, {'itmes': ['11013331', '9843236'], 'type': 'KAT'}]

Handling onchange event in HTML.DropDownList Razor MVC

Description

You can use another overload of the DropDownList method. Pick the one you need and pass in a object with your html attributes.

Sample

@Html.DropDownList("CategoryID", null, new { @onchange="location = this.value;" })

More Information

CSS display:inline property with list-style-image: property on <li> tags

I would suggest not to use list-style-image, as it behaves quite differently in different browsers, especially the image position

instead, you can use something like this

ol.widgets,
ol.widgets li { list-style: none; }
ol.widgets li { padding-left: 20px; backgroud: transparent ("image") no-repeat x y; }

it works in all browsers and would give you the identical result in different browsers.

Multiple SQL joins

 SELECT
 B.Title, B.Edition, B.Year, B.Pages, B.Rating     --from Books
, C.Category                                        --from Categories
, P.Publisher                                       --from Publishers
, W.LastName                                        --from Writers

FROM Books B

JOIN Categories_Books CB ON B._ISBN = CB._Books_ISBN
JOIN Categories_Books CB ON CB.__Categories_Category_ID = C._CategoryID
JOIN Publishers P ON B.PublisherID = P._Publisherid
JOIN Writers_Books WB ON B._ISBN = WB._Books_ISBN
JOIN Writers W ON WB._Writers_WriterID = W._WriterID

Setting the number of map tasks and reduce tasks

Folks from this theory it seems we cannot run map reduce jobs in parallel.

Lets say I configured total 5 mapper jobs to run on particular node.Also I want to use this in such a way that JOB1 can use 3 mappers and JOB2 can use 2 mappers so that job can run in parallel. But above properties are ignored then how can execute jobs in parallel.

Why does SSL handshake give 'Could not generate DH keypair' exception?

The answer above is correct, but in terms of the workaround, I had problems with the BouncyCastle implementation when I set it as preferred provider:

java.lang.ArrayIndexOutOfBoundsException: 64
    at com.sun.crypto.provider.TlsPrfGenerator.expand(DashoA13*..)

This is also discussed in one forum thread I found, which doesn't mention a solution. http://www.javakb.com/Uwe/Forum.aspx/java-programmer/47512/TLS-problems

I found an alternative solution which works for my case, although I'm not at all happy with it. The solution is to set it so that the Diffie-Hellman algorithm is not available at all. Then, supposing the server supports an alternative algorithm, it will be selecting during normal negotiation. Obviously the downside of this is that if somebody somehow manages to find a server that only supports Diffie-Hellman at 1024 bits or less then this actually means it will not work where it used to work before.

Here is code which works given an SSLSocket (before you connect it):

List<String> limited = new LinkedList<String>();
for(String suite : ((SSLSocket)s).getEnabledCipherSuites())
{
    if(!suite.contains("_DHE_"))
    {
        limited.add(suite);
    }
}
((SSLSocket)s).setEnabledCipherSuites(limited.toArray(
    new String[limited.size()]));

Nasty.

Unmount the directory which is mounted by sshfs in Mac

You can always do this from finder. Simply navigate to the directory above where the mount is and hit the eject icon over the mounted folder, which will have SSHFS in the name (in the finder). A shortcut to open a folder in the finder from the terminal is

open .

which will open up the current directory in a new finder window. Replace "." with your directory of choice.

Finding an elements XPath using IE Developer tool

You can find/debug XPath/CSS locators in the IE as well as in different browsers with the tool called SWD Page Recorder

The only restrictions/limitations:

  1. The browser should be started from the tool
  2. Internet Explorer Driver Server - IEDriverServer.exe - should be downloaded separately and placed near SwdPageRecorder.exe

How can I resolve "Your requirements could not be resolved to an installable set of packages" error?

Run this command:

composer install --ignore-platform-reqs

or

composer update --ignore-platform-reqs

Why do we need C Unions?

In early versions of C, all structure declarations would share a common set of fields. Given:

struct x {int x_mode; int q; float x_f};
struct y {int y_mode; int q; int y_l};
struct z {int z_mode; char name[20];};

a compiler would essentially produce a table of structures' sizes (and possibly alignments), and a separate table of structures' members' names, types, and offsets. The compiler didn't keep track of which members belonged to which structures, and would allow two structures to have a member with the same name only if the type and offset matched (as with member q of struct x and struct y). If p was a pointer to any structure type, p->q would add the offset of "q" to pointer p and fetch an "int" from the resulting address.

Given the above semantics, it was possible to write a function that could perform some useful operations on multiple kinds of structure interchangeably, provided that all the fields used by the function lined up with useful fields within the structures in question. This was a useful feature, and changing C to validate members used for structure access against the types of the structures in question would have meant losing it in the absence of a means of having a structure that can contain multiple named fields at the same address. Adding "union" types to C helped fill that gap somewhat (though not, IMHO, as well as it should have been).

An essential part of unions' ability to fill that gap was the fact that a pointer to a union member could be converted into a pointer to any union containing that member, and a pointer to any union could be converted to a pointer to any member. While the C89 Standard didn't expressly say that casting a T* directly to a U* was equivalent to casting it to a pointer to any union type containing both T and U, and then casting that to U*, no defined behavior of the latter cast sequence would be affected by the union type used, and the Standard didn't specify any contrary semantics for a direct cast from T to U. Further, in cases where a function received a pointer of unknown origin, the behavior of writing an object via T*, converting the T* to a U*, and then reading the object via U* would be equivalent to writing a union via member of type T and reading as type U, which would be standard-defined in a few cases (e.g. when accessing Common Initial Sequence members) and Implementation-Defined (rather than Undefined) for the rest. While it was rare for programs to exploit the CIS guarantees with actual objects of union type, it was far more common to exploit the fact that pointers to objects of unknown origin had to behave like pointers to union members and have the behavioral guarantees associated therewith.

How to filter for multiple criteria in Excel?

The regular filter options in Excel don't allow for more than 2 criteria settings. To do 2+ criteria settings, you need to use the Advanced Filter option. Below are the steps I did to try this out.

http://www.bettersolutions.com/excel/EDZ483/QT419412321.htm

Set up the criteria. I put this above the values I want to filter. You could do that or put on a different worksheet. Note that putting the criteria in rows will make it an 'OR' filter and putting them in columns will make it an 'AND' filter.

  1. E1 : Letters
  2. E2 : =m
  3. E3 : =h
  4. E4 : =j

I put the data starting on row 5:

  1. A5 : Letters
  2. A6 :
  3. A7 :
  4. ...

Select the first data row (A6) and click the Advanced Filter option. The List Range should be pre-populated. Select the Criteria range as E1:E4 and click OK.

That should be it. Note that I use the '=' operator. You will want to use something a bit different to test for file extensions.

Java client certificates over HTTPS/SSL

Finally solved it ;). Got a strong hint here (Gandalfs answer touched a bit on it as well). The missing links was (mostly) the first of the parameters below, and to some extent that I overlooked the difference between keystores and truststores.

The self-signed server certificate must be imported into a truststore:

keytool -import -alias gridserver -file gridserver.crt -storepass $PASS -keystore gridserver.keystore

These properties need to be set (either on the commandline, or in code):

-Djavax.net.ssl.keyStoreType=pkcs12
-Djavax.net.ssl.trustStoreType=jks
-Djavax.net.ssl.keyStore=clientcertificate.p12
-Djavax.net.ssl.trustStore=gridserver.keystore
-Djavax.net.debug=ssl # very verbose debug
-Djavax.net.ssl.keyStorePassword=$PASS
-Djavax.net.ssl.trustStorePassword=$PASS

Working example code:

SSLSocketFactory sslsocketfactory = (SSLSocketFactory) SSLSocketFactory.getDefault();
URL url = new URL("https://gridserver:3049/cgi-bin/ls.py");
HttpsURLConnection conn = (HttpsURLConnection)url.openConnection();
conn.setSSLSocketFactory(sslsocketfactory);
InputStream inputstream = conn.getInputStream();
InputStreamReader inputstreamreader = new InputStreamReader(inputstream);
BufferedReader bufferedreader = new BufferedReader(inputstreamreader);

String string = null;
while ((string = bufferedreader.readLine()) != null) {
    System.out.println("Received " + string);
}

Could not open a connection to your authentication agent

I just got this working. Open your ~/.ssh/config file.

Append the following-

Host github.com
 IdentityFile ~/.ssh/github_rsa

The page that gave me the hint Set up SSH for Git said that the single space indentation is important... though I had a configuration in here from Heroku that did not have that space and works properly.

How to update single value inside specific array item in redux

In my case I did something like this, based on Luis's answer:

...State object...
userInfo = {
name: '...',
...
}

...Reducer's code...
case CHANGED_INFO:
return {
  ...state,
  userInfo: {
    ...state.userInfo,
    // I'm sending the arguments like this: changeInfo({ id: e.target.id, value: e.target.value }) and use them as below in reducer!
    [action.data.id]: action.data.value,
  },
};

How do I concatenate const/literal strings in C?

Assuming you have a char[fixed_size] rather than a char*, you can use a single, creative macro to do it all at once with a <<cout<<like ordering ("rather %s the disjointed %s\n", "than", "printf style format"). If you are working with embedded systems, this method will also allow you to leave out malloc and the large *printf family of functions like snprintf() (This keeps dietlibc from complaining about *printf too)

#include <unistd.h> //for the write example
//note: you should check if offset==sizeof(buf) after use
#define strcpyALL(buf, offset, ...) do{ \
    char *bp=(char*)(buf+offset); /*so we can add to the end of a string*/ \
    const char *s, \
    *a[] = { __VA_ARGS__,NULL}, \
    **ss=a; \
    while((s=*ss++)) \
         while((*s)&&(++offset<(int)sizeof(buf))) \
            *bp++=*s++; \
    if (offset!=sizeof(buf))*bp=0; \
}while(0)

char buf[256];
int len=0;

strcpyALL(buf,len,
    "The config file is in:\n\t",getenv("HOME"),"/.config/",argv[0],"/config.rc\n"
);
if (len<sizeof(buf))
    write(1,buf,len); //outputs our message to stdout
else
    write(2,"error\n",6);

//but we can keep adding on because we kept track of the length
//this allows printf-like buffering to minimize number of syscalls to write
//set len back to 0 if you don't want this behavior
strcpyALL(buf,len,"Thanks for using ",argv[0],"!\n");
if (len<sizeof(buf))
    write(1,buf,len); //outputs both messages
else
    write(2,"error\n",6);
  • Note 1, you typically wouldn't use argv[0] like this - just an example
  • Note 2, you can use any function that outputs a char*, including nonstandard functions like itoa() for converting integers to string types.
  • Note 3, if you are already using printf anywhere in your program there is no reason not to use snprintf(), since the compiled code would be larger (but inlined and significantly faster)

Get Insert Statement for existing row in MySQL

In PHPMyAdmin you can:

  1. click copy on the row you want to know its insert statements SQL:

Select copy

  1. click Preview SQL:

Select Preview

  1. you will get the created insert statement that generates it

You can apply that on many rows at once if you select them and click copy from the bottom of the table and then Preview SQl

Add column in dataframe from list

You can also use df.assign:

In [1559]: df
Out[1559]: 
   A   B   C
0  0 NaN NaN
1  4 NaN NaN
2  5 NaN NaN
3  6 NaN NaN
4  7 NaN NaN
5  7 NaN NaN
6  6 NaN NaN
7  5 NaN NaN

In [1560]: mylist = [2,5,6,8,12,16,26,32]

In [1567]: df = df.assign(D=mylist)

In [1568]: df
Out[1568]: 
   A   B   C   D
0  0 NaN NaN   2
1  4 NaN NaN   5
2  5 NaN NaN   6
3  6 NaN NaN   8
4  7 NaN NaN  12
5  7 NaN NaN  16
6  6 NaN NaN  26
7  5 NaN NaN  32

Where is `%p` useful with printf?

At least on one system that is not very uncommon, they do not print the same:

~/src> uname -m
i686
~/src> gcc -v
Using built-in specs.
Target: i686-pc-linux-gnu
[some output snipped]
gcc version 4.1.2 (Gentoo 4.1.2)
~/src> gcc -o printfptr printfptr.c
~/src> ./printfptr
0xbf8ce99c
bf8ce99c

Notice how the pointer version adds a 0x prefix, for instance. Always use %p since it knows about the size of pointers, and how to best represent them as text.

Getting the 'external' IP address in Java

An alternative solution is to execute an external command, obviously, this solution limits the portability of the application.

For example, for an application that runs on Windows, a PowerShell command can be executed through jPowershell, as shown in the following code:

public String getMyPublicIp() {
    // PowerShell command
    String command = "(Invoke-WebRequest ifconfig.me/ip).Content.Trim()";
    String powerShellOut = PowerShell.executeSingleCommand(command).getCommandOutput();

    // Connection failed
    if (powerShellOut.contains("InvalidOperation")) {
        powerShellOut = null;
    }
    return powerShellOut;
}