null-coalescing-operator Questions

7

Solved

If I have code similar to the following: while(myDataReader.Read()) { myObject.intVal = Convert.ToInt32(myDataReader["mycolumn"] ?? 0); } It throws the error: Object cannot be cast from DBNu...
Limestone asked 24/2, 2012 at 19:29

6

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Is there any shorthand in c# now that will cutdown the following code: var testVar1 = checkObject(); if (testVar1 != null) { testVar2 = testVar1; } In this situation only want to assign testVar...
Skepticism asked 6/6, 2019 at 21:58

16

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In C# there's a null-coalescing operator (written as ??) that allows for easy (short) null checking during assignment: string s = null; var other = s ?? "some default value"; Is there a python e...
Diagonal asked 12/2, 2011 at 15:4

5

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Is it possible to implement the ?? operator in Ruby? a = nil b = 1 x = a ?? b # x should == 1 x = b ?? 2 # x should == 1
Improvise asked 4/6, 2009 at 21:28

2

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I am trying to use the null-coalescing operator in a C# script in Unity, my project Scripting Runtime is set to .NET 4.x so it should work correctly. The problem is that even though the LEFT opera...
Keeling asked 3/7, 2019 at 18:1

10

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Is there a C++ equivalent for C# null coalescing operator? I am doing too many null checks in my code. So was looking for a way to reduce the amount of null code.
Faceharden asked 23/11, 2009 at 19:31

16

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Is there a null coalescing operator in powershell? I'd like to be able to do these c# commands in powershell: var s = myval ?? "new value"; var x = myval == null ? "" : otherval;
Quinlan asked 16/5, 2012 at 17:49

3

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Is there a way to supply a name to a function that then returns the value of either the field or property on a given object with that name? I tried to work around it with the null-coalesce operator...
Apocynthion asked 30/4, 2013 at 17:18

2

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Is there a way to do an assignment only if the assigned value is not None, and otherwise do nothing? Of course we can do: x = get_value() if get_value() is not None but this will read the value...
Owl asked 17/1, 2020 at 1:33

4

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Or how do I make this thing work? I have an Interval object: class Interval(Base): __tablename__ = 'intervals' id = Column(Integer, primary_key=True) start = Column(DateTime) end = Column(Dat...
Hyatt asked 7/8, 2013 at 11:23

19

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Is there a null coalescing operator in Javascript? For example, in C#, I can do this: String someString = null; var whatIWant = someString ?? "Cookies!"; The best approximation I can figure out...

3

I'm encountering some strange behavior. When running this piece of code: var foo = await actionContext.RequestContext?.Principal?.ToUserTokenAsync() ?? UserToken.UnidentifiedUser; Principal is ...
Excurrent asked 3/6, 2019 at 12:37

2

I'm looking for a way to do undefined coalescing in javascript with booleans. I'm used to doing the following, for, say, positive integers: var x = i1 || i2 || i3 || i4; This is a 'slick' way, b...
Jelly asked 25/11, 2015 at 21:46

2

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Php 8.0 introduced the nullsafe operator which can be used like so $foo?->bar?->baz;. I have a code sample running on php 8.1 that throws the error Undefined property: stdClass::$first_name e...
Shurwood asked 12/4, 2022 at 16:13

10

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Many programming languages have a coalesce function (returns the first non-NULL value, example). PHP, sadly in 2009, does not. What would be a good way to implement one in PHP until PHP itself get...
Rules asked 18/6, 2009 at 15:49

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Say I have this: $username = (string) $inputs['username'] ?? null; If $inputs['username'] is set then I want it to cast to string. If it's not set then $username should be null. However, at the...
Jacobean asked 14/5, 2018 at 20:26

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Something I find myself doing more and more is checking a string for empty (as in "" or null) and a conditional operator. A current example: s.SiteNumber.IsNullOrEmpty() ? "No Number" : s.SiteNum...
Pow asked 10/3, 2010 at 20:1

3

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I have recently found a problem with the null-coalescing operator while using Json.NET to parse JSON as dynamic objects. Suppose this is my dynamic object: string json = "{ \"phones\": { \"persona...
Dm asked 14/3, 2015 at 17:0

14

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Can someone explain the differences between ternary operator shorthand (?:) and null coalescing operator (??) in PHP? When do they behave differently and when in the same way (if that even happens)...

7

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I'm tempted to lie and say that English is my second language, but the truth is that I just have no idea what 'Coalescing' means. I know what ?? 'does' in C#, but the name doesn't make sense to me....
Lyontine asked 20/4, 2009 at 21:31

4

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I'm trying to safely check if an IList<> is not empty. var Foo = Bar.GimmeIListT(); // Returns an IList<SomeObject> if (Foo?.Any()) // Do cool stuff with items in Foo But there is a...
Clinandrium asked 18/7, 2017 at 10:5

4

What is the equivalent of null coalescing operator (??) in angular 2? In C# we can perform this operation: string str = name ?? FirstName ?? "First Name is null";
Dreiser asked 8/4, 2017 at 18:14

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Ran across this line of code: FormsAuth = formsAuth ?? new FormsAuthenticationWrapper(); What do the two question marks mean, is it some kind of ternary operator? It's hard to look up in Google....
Laverty asked 15/1, 2009 at 14:3

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I need to add numerous variables of type nullable int. I used the null coalescing operator to get it down to one variable per line, but I have a feeling there is a more concise way to do this, e.g....
Nuno asked 30/8, 2010 at 10:6

0

Using Visual Studio 2019 with ReSharper (both on the latest version) I an unable to get intellisense to stop complaining about ECMAScript 2020 features like the null-coalescing operator (??). The c...

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