Questions tagged [null]
Null means *nothing* or *unknown*, depending on context. Please use the "sql-null" tag for SQL specific questions.
16,353
questions
2
votes
2
answers
39
views
How to handle the possibility of expected null properties in a LINQ were clause?
Consider the following C# Code Fragment:
public class Person
{
public int Id { get; set;}
public string? Name { get; set;}
public string? Description {get; set;}
}
List<Person>? ...
0
votes
0
answers
38
views
Blazor C# Error: One or more errors occurred. (Value cannot be null. (Parameter 'value'))
I am new to Blazor Development. Does any know how to solve this issue? I only have this issue if I login as a user. When I try to step into the code. It stop after the ApplicationDbContext class ...
- 1
0
votes
1
answer
23
views
Elasticsearch: how to drop the properties from being stored if the value is null
We have an index template with can up to 150 properties. Some properties will have value as null depend on the field called "RecordType".
How Elasticsearch can drop the properties having ...
- 1
-2
votes
0
answers
45
views
Unmarshal JSON nulls as nil slices [closed]
Is there a convenient way to have null JSON fields unmarshal as nil slices instead of empty slices? I know I could make the slices be pointers to slices instead (so nulls unmarshal as nil pointers), ...
- 373
-1
votes
0
answers
73
views
Why am I seeing NaN in the correlation matrix? [closed]
# Fill all types of missing values with zero
first_chunk.replace(to_replace=[None, 'None', 'none', 'Na', 'NA', 'na', 'N/A', 'n/a', '', ' '], value=0, inplace=True)
first_chunk.fillna(0, inplace=True)
...
- 16.4k
0
votes
1
answer
26
views
Null characters in between my log_file.txt in Powershell [duplicate]
Usually this txt shows the logs of my program running. Nothing was changed and it started now spitting out null characters.
Not really sure what to do. Is this any unicode issue? The code does not ...
0
votes
1
answer
25
views
How to compare a column is not null in superset ( Metrics -> Custom SQL)?
I want to create a metric of Pivot 2: Actual/Target. But some Target is null. I wrote in Custom SQL as below but it did not work. I changed it to != Null or !=0, but it still does not work. Please ...
-1
votes
0
answers
25
views
When i try to update value of the code if i leave this field null it encounter an error and program exit [duplicate]
When i choose update product and leave warrantyPeriod blank this error occur
Enter new warranty period (leave blank to keep unchanged):
Exception in thread "main" java.lang....
0
votes
1
answer
27
views
The return type 'Null' isn't a 'University', as required by the closure's context
I'm stuck trying to test my code. but I get the error that "The return type 'Null' isn't a 'University', as required by the closure's context.
Any suggestions on how to fix this?
Here's the code:
...
- 1
0
votes
0
answers
9
views
nifi 1.23.2 string type value is not allowed to be defaulted to null
nifi was upgraded to 1.23.2 and we found a potential incompatibility issue:
We have some messages serialized based on this schema:
{"name":"myKey","type":"string&...
- 199
0
votes
2
answers
91
views
How to test a C pointer for whether it points to a struct
I have a linked list structure
struct node {
int data;
node next;
}
and a function
struct node *insert_sorted (struct node *nodes,
int d) {
// todo
}
I need to implement this so that, given a ...
- 3,821
0
votes
0
answers
17
views
Populating Null in an INT column of MySQL Table [duplicate]
I have data as follows in my csv:
ID, NAME, fav_digit
1 abc 2
2 xyz
3 pqr 7
Now, I have created the table in the MySQL table using the data types Int, Varchar(7), Int respectively.
...
-2
votes
2
answers
42
views
Handling Null Values For Unmatched Rows in a Left Join SQL
Sorry for the horrible first part of the question. Tried to explain with example in second part.
I have two tables a, b. I am left joining these two tables based on three columns to retrieve a column '...
-8
votes
4
answers
177
views
Is (p == NULL) the same as (*p == 0) in C++?
My C++ code has the following:
if (p == NULL || *p == 0)
I wonder if this is redundant?
Is (p == NULL) the same as (*p == 0)?
Why or why not?
- 1,569
1
vote
3
answers
197
views
What is a "known bad pointer value"?
In this answer to this question, it was noted that:
If you're going to 'clear' the pointer in the dtor, a different idiom would be better - set the pointer to a known bad pointer value.
and also ...
- 33