nullable Questions
4
Solved
I have a list:
List<int, SomeStruct>
For some reason, it is not allowing me to assign null values to it. What do I do if I want to have no struct associated?
2
Solved
In the code below:
void Main()
{
DateTime cleanDate = DateTime.Now.ToCleanDateTime();
DateTime? nullableCleanDate = DateTime.Now;
nullableCleanDate = nullableCleanDate.ToCleanDateTime();
cle...
1
Solved
In Spark, literal columns, when added, are not nullable:
from pyspark.sql import SparkSession, functions as F
spark = SparkSession.builder.getOrCreate()
df = spark.createDataFrame([(1,)], ['c1'])
...
Putdown asked 29/7, 2021 at 14:56
3
Solved
As I learn new components in Kotlin, I came accross requireNotNull and checkNotNull but the only difference I've found is that requireNotNull can throw an IllegalArgumentException while checkNotNul...
Inhospitality asked 25/7, 2021 at 18:28
4
Solved
If I have a nullable type Xyz?, I want to reference it or convert it to a non-nullable type Xyz. What is the idiomatic way of doing so in Kotlin?
For example, this code is in error:
val something:...
Deliciadelicious asked 28/12, 2015 at 18:13
3
Solved
I have a class i want to change the properties of in the editor. So i made my class System.Serializable and made the variables public that i want to be able to change.
Like so:
[System.Serializab...
Ulric asked 17/10, 2018 at 11:45
9
Solved
I use the "bool" type for variables as I was used to in C++, and I try to put the values of functions or properties I expect to be boolean into my variable. However I often encounter cases where th...
2
I have just enabled null checking in my .net core 3.1 project.
The problem is that I have a response class
public class DecryptResponse
{
public DecryptStatus Status { get; set; }
//This is t...
Dopester asked 28/5, 2020 at 13:25
6
Solved
I am trying to serialize a class several of the data-members are Nullable objects, here is a example
[XmlAttribute("AccountExpirationDate")]
public Nullable<DateTime> AccountExpirat...
Lumpkin asked 15/1, 2010 at 19:32
4
Solved
Let's say I have this:
PriorityType? priority;
string userInput = ...;
I cannot change how this is defined: PriorityType? priority because it's actually part of a contract with another piece of ...
7
Solved
Quoting from an answer from this question.
Guid is a value type, so a variable of type Guid can't be null to
start with.
What then if I see this?
public Nullable<System.Guid> SomePrope...
20
How do I convert a nullable int to an int? Suppose I have 2 type of int as below:
int? v1;
int v2;
I want to assign v1's value to v2. v2 = v1; will cause an error. How do I convert v1 to v2?
2
Solved
I need to determine if a generic type is a String, bool, int, double or another class at runtime. I didn't found a way to do it for nullable types:
class Foo<T> {
void foo() {
if (T == int...
3
Solved
num should be nullable when set, but what it returns should always be non-nullable (have a default value).
class Test {
var num: Int? = null
get() = field ?: 5 // default value if null
}
The f...
Inlay asked 6/10, 2017 at 13:9
7
Solved
I have some C# code with the following array declaration. Note the single ? after Color.
private Color?[,] scratch;
In my investigating I have found that if you you have code such as:
int? a;
...
9
Solved
So, I asked a question this morning, which I did not phrase correctly, so I got a lot of responses as to why NULL compared to anything will give NULL/FALSE.
My actual question was, what is the ti...
3
Solved
Problem
What is the idiomatic way of working around this limitation of the null-safety in the Kotlin type system?
val strs1:List<String?> = listOf("hello", null, "world")
...
1
Solved
Supposing I have a class like this:
public class BridgeFormModel
{
[Required]
[Display( Name = "What is your name?" )]
public String? Name { get; set; }
[Required]
[Display( Name = ...
Merissa asked 20/3, 2021 at 21:53
19
Solved
My model has a boolean that has to be nullable
public bool? Foo
{
get;
set;
}
so in my Razor cshtml I have
@Html.CheckBoxFor(m => m.Foo)
except that doesn't work. Neither does casting it...
Torrez asked 27/7, 2011 at 19:2
3
Solved
Is it possible to make the following code to compile in Kotlin?
val variable: String? = "string"
val (a, b) = variable?.run {
1 to 2
}
Landseer asked 4/3, 2020 at 19:27
13
Solved
Java 1.8 is receiving the Optional<T> class, that allows us to explicitly say when a method may return a null value and "force" its consumer to verify if it is not null (isPresent()...
Neutralism asked 24/4, 2013 at 18:9
2
Solved
This program has two errors:
using System;
T? f<T>(T? t)
{
t = null; // Error CS0403 Cannot convert null to type parameter 'T' because it could be a non-nullable value type
return default...
4
Solved
Can someone give me a list, or point me to where I can find a list of C# data types that can be a nullable type?
For example:
I know that Nullable<int> is ok
I know that Nullable<byte[...
4
Solved
Take a look at this kotlin one liner:
val nonNullArr : List<NonNullType> = nullArray.filter {it != null}
The compiler gives a type error at this line, saying that a list of nullables can't...
Morganica asked 15/2, 2019 at 13:20
2
I have the following DropDownList in an ASP.NET MVC cshtml page:
@Html.DropDownListFor(model => model.GroupId, (IEnumerable<SelectListItem>)ViewBag.PossibleGroups, "")
The property is d...
Protecting asked 4/3, 2014 at 21:23
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