It&#39;s any of these:

    Dim variable As T
    Dim variable As T = Nothing
    Dim variable As New T()
    Dim variable As T = CType(Nothing, T) &#39;this is suggested by reflector

Assigning `Nothing` even to value types is perfectly fine in VB.NET. And the latter is only possible if you specify either `New`, or `Structure` constraint for the generic type.


The closest equivalent to `default(T)` is really `CType(Nothing, T)` since it can be used in any context that `default(T)` is used (i.e. as an expression).

So I am a new programmer and I just installed XCode on my Macbook to get the GCC. I think Xcode is the only way for getting GCC on OSX. Now when I run my Hello World application, in C++, g++ comes up saying it is version 4.0.1 but when I look for commands starting with g I also see g++-4.2. Is there any way of making 4.2 default rather than 4.0.1, and also is there a way to updating gcc to the latest version 4.4.0?

EDIT: Ok, so I installed macports and installed gcc4.4 and it shows up on terminal as gcc-mp-4.4 and how do I make it default with gcc_select, like what are the commands and stuff. Thanks.

Update GCC on OSX

How do you replace all instances of one string with another in javascript?
Example:

    someString = &#39;the cat looks like a cat&#39;
    anotherString = someString.replace(&#39;cat&#39;, &#39;dog&#39;);

results in anotherString being set to &#39;the **dog** looks like a **cat**&#39;, and I would like it to be &#39;the **dog** looks like a **dog**&#39;

Javascript multiple replace

What is VB&#39;s equivalent for C#&#39;s `default(T)` - the [default operator][1]


  [1]: https://docs.microsoft.com/en-us/dotnet/csharp/language-reference/operators/default

VB equivalent for C#&#39;s default(T)

<p>What is VB's equivalent for C#'s <code>default(T)</code> - the <a href="https://docs.microsoft.com/en-us/dotnet/csharp/language-reference/operators/default" target="_blank" rel="noopener noreferrer">default operator</a></p>


I&#39;ve read that it&#39;s unwise to use ToUpper and ToLower to perform case-insensitive string comparisons, but I see no alternative when it comes to LINQ-to-SQL. The ignoreCase and CompareOptions arguments of String.Compare are ignored by LINQ-to-SQL (if you&#39;re using a case-sensitive database, you get a case-sensitive comparison even if you ask for a case-insensitive comparison).  Is ToLower or ToUpper the best option here?  Is one better than the other?  I thought I read somewhere that ToUpper was better, but I don&#39;t know if that applies here.  (I&#39;m doing a lot of code reviews and everyone is using ToLower.)

    Dim s = From row In context.Table Where String.Compare(row.Name, &quot;test&quot;, StringComparison.InvariantCultureIgnoreCase) = 0

This translates to an SQL query that simply compares row.Name with &quot;test&quot; and will not return &quot;Test&quot; and &quot;TEST&quot; on a case-sensitive database.

Case insensitive string compare in LINQ-to-SQL

As a non-.NET programmer I&#39;m looking for the .NET equivalent of the old Visual Basic function `left(string, length)`. It was lazy in that it worked for any length string. As expected, `left(&quot;foobar&quot;, 3) = &quot;foo&quot;` while, most helpfully, `left(&quot;f&quot;, 3) = &quot;f&quot;`.

In .NET `string.Substring(index, length)` throws exceptions for everything out of range. In Java I always had the Apache-Commons lang.StringUtils handy. In Google I don&#39;t get very far searching for string functions.

&lt;hr/&gt;

**@Noldorin** - Wow, thank you for your VB.NET extensions! My first encounter, although it took me several seconds to do the same in C#:

    public static class Utils
    {
        public static string Left(this string str, int length)
        {
            return str.Substring(0, Math.Min(length, str.Length));
        }
    }

Note the static class and method as well as the `this` keyword. Yes, they are as simple to invoke as `&quot;foobar&quot;.Left(3)`. See also [C# extensions on MSDN][1].

  [1]: http://msdn.microsoft.com/en-us/library/bb383977.aspx


.NET equivalent of the old vb left(string, length) function

I need a regular expression that I can use in VBScript and .NET that will return only the numbers that are found in a string. 

For Example any of the following &quot;strings&quot; should return only **1231231234**

- 123 123 1234
- (123) 123-1234
- 123-123-1234
- (123)123-1234
- 123.123.1234
- 123  123 1234
- 1 2 3 1 2 3 1 2 3 4

This will be used in an email parser to find telephone numbers that customers may provide in the email and do a database search.

I may have missed a similar regex but I did search on regexlib.com.

[EDIT] - Added code generated by [RegexBuddy][1] after setting up musicfreak&#39;s answer

**VBScript Code**

    Dim myRegExp, ResultString
    Set myRegExp = New RegExp
    myRegExp.Global = True
    myRegExp.Pattern = &quot;[^\d]&quot;
    ResultString = myRegExp.Replace(SubjectString, &quot;&quot;)

**VB.NET**

    Dim ResultString As String
    Try
          Dim RegexObj As New Regex(&quot;[^\d]&quot;)
          ResultString = RegexObj.Replace(SubjectString, &quot;&quot;)
    Catch ex As ArgumentException
          &#39;Syntax error in the regular expression
    End Try

**C#**

    string resultString = null;
    try {
    	Regex regexObj = new Regex(@&quot;[^\d]&quot;);
    	resultString = regexObj.Replace(subjectString, &quot;&quot;);
    } catch (ArgumentException ex) {
    	// Syntax error in the regular expression
    }


  [1]: http://www.regexbuddy.com/

return only Digits 0-9 from a String

How can I parse a string in VB.NET to enum value?

Example I have this enum:

    Public Enum Gender
        NotDefined
        Male
        Female
    End Enum

how can I convert a string &quot;Male&quot; to the `Gender` enum&#39;s `Male` value?

Parse a string to an Enum value in VB.NET

I would like to append one DataTable to another DataTable. I see the DataTable class has two methods; &quot;Load(IDataReader)&quot; and &quot;Merge(DataTable)&quot;.  From the documentation, both appear to &#39;merge&#39; the incoming data with the existing DataTable if rows exist. I will be doing the merge in a data access layer.

I could use an `IDataReader` and use the Load method to merge the DataTables. Or I could load a DataSet using the `IDataReader`, get the DataTable from the DataSet, and then use the Merge method to merge the DataTables.

I was wondering if someone could tell me which is the proper method to use?

Alternatively, let me know if you have a different suggestion on how to accomplish this task.

How to append one DataTable to another DataTable

As title, how can I set a table&#39;s column to have the default value the current year and month, in format &#39;YYYYMM&#39;, like 200905 for today?

How to set a Postgresql default value datestamp like &#39;YYYYMM&#39;?

I have googled this and keep coming up with &quot;No it is not possible&quot; but these posts were dated 2005-2007 so I&#39;m wondering if this has been changed. A code example:

    CREATE PROCEDURE `blah`
    (
      myDefaultParam int = 0 -- This breaks the code for some reason
    )
    BEGIN
      -- Do something here
    END

One of the solutions has been to pass null and then check for null and set the variable. I don&#39;t want to do that and I shouldn&#39;t have to. If this is true then MySql devs need to wake up because there is so much more I could do with MSSQL.

Is it possible to have a default parameter for a mysql stored procedure?

I know that instantiated arrays of value types in C# are automatically populated with the [default value of the type][1] (e.g. false for bool, 0 for int, etc.).

Is there a way to auto-populate an array with a seed value that&#39;s not the default? Either on creation or a built-in method afterwards (like Java&#39;s [Arrays.fill()](https://docs.oracle.com/javase/8/docs/api/java/util/Arrays.html#fill-int:A-int-))? Say I wanted an boolean array that was true by default, instead of false.  Is there a built-in way to do this, or do you just have to iterate through the array with a for loop?

     // Example pseudo-code:
     bool[] abValues = new[1000000];
     Array.Populate(abValues, true);

     // Currently how I&#39;m handling this:
     bool[] abValues = new[1000000];
     for (int i = 0; i &lt; 1000000; i++)
     {
         abValues[i] = true;
     }

Having to iterate through the array and &quot;reset&quot; each value to true seems ineffecient.  Is there anyway around this?  Maybe by flipping all values?

After typing this question out and thinking about it, I&#39;m guessing that the default values are simply a result of how C# handles the memory allocation of these objects behind the scenes, so I imagine it&#39;s probably not possible to do this.  But I&#39;d still like to know for sure!


  [1]: http://msdn.microsoft.com/en-us/library/83fhsxwc(loband).aspx

How to populate/instantiate a C# array with a single value?

Is it possible to give a default value to a parameter of a function while we are passing the parameter by reference. in C++

For example, when I try to declare a function like:

    virtual const ULONG Write(ULONG &amp;State = 0, bool sequence = true);

When I do this it gives an error:

&gt;error C2440: &#39;default argument&#39; : cannot convert from &#39;const int&#39; to &#39;unsigned long &amp;&#39;
A reference that is not to &#39;const&#39; cannot be bound to a non-lvalue


Default value to a parameter while passing by reference in C++

[C++ Notes: Array Initialization](http://www.fredosaurus.com/notes-cpp/arrayptr/array-initialization.html) has a nice list over initialization of arrays. I have a

    int array[100] = {-1};

expecting it to be full with -1&#39;s but its not, only first value is and the rest are 0&#39;s mixed with random values.

The code

    int array[100] = {0};

works just fine and sets each element to 0.

What am I missing here.. Can&#39;t one initialize it if the value isn&#39;t zero ?

And 2: Is the default initialization (as above) faster than the usual loop through the whole array and assign a value or does it do the same thing?


Content Type	Original Author	Original Content on Stackoverflow
Question	Hath	View Question on Stackoverflow
Solution 1 - vb.net	Anton Gogolev	View Answer on Stackoverflow
Solution 2 - vb.net	panopticoncentral	View Answer on Stackoverflow

VB equivalent for C#'s default(T)

vb.net Problem Overview

vb.net Solutions

Solution 1 - vb.net

Solution 2 - vb.net

Javascript multiple replace

Update GCC on OSX

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