null Questions
6
Solved
I have a Dataframe that I am trying to flatten. As part of the process, I want to explode it, so if I have a column of arrays, each value of the array will be used to create a separate row. For ins...
Fingertip asked 28/9, 2016 at 5:57
12
Solved
In if statements, I am used to seeing x != null, and reading it as "x is not null".
But in function names, having to say 'NotNull' or 'IsNotNull' to explain a similar state feels ov...
Library asked 11/1, 2013 at 7:47
3
Solved
This is bugging me for several days now. I know about the standard stream redirection to the NUL device, but this isn't the case. node.js uses CreateFileW under its fs native/libuv bindings.
Unfor...
3
Solved
I have a MySQL table which has about 30 columns. One column has empty values for the majority of the table. How can I use a MySQL command to filter out the items which do have values in the table?
...
6
Solved
I defined a linked list in C++. I am trying to set a NULL value to the variable head (in the constructor of Movie_LinkedList), but I got:
movie.h(40): error C2065: 'NULL' : undeclared identifier
pl...
2
Solved
You create a script, it works for some time, then out of the blue it starts crashing with "You cannot call a method on a null-valued expression" or "The property 'property name' cannot be found on ...
Hoggish asked 10/7, 2015 at 7:43
10
Solved
How do I refer to the null object in Python?
3
Solved
I am trying to obtain all rows in a dataframe where two flags are set to '1' and subsequently all those that where only one of two is set to '1' and the other NOT EQUAL to '1'
With the following s...
Kirstinkirstyn asked 24/8, 2016 at 10:36
20
How can I check a string against null in java? I am using
stringname.equalsignorecase(null)
but it's not working.
7
Solved
If I have an array:
[null, 'a', 'b', 'c']
I want to get the first non-null value from the array, in this case "a". How could I go about doing that nice and easily?
5
Hi how this problem solvedenter image description here
I added the widget "dropdown_formfield: ^0.1.4" to my project and it showed this error How can I fix this problem please help. This ...
Holocaine asked 17/3, 2023 at 10:45
4
Solved
3
Solved
I'm hoping this is an easy fix. Whenever I run levels(df) am I given a NULL output. This isn't specific to my data frame as it occurs with any set of data that I use. I am thinking that there may b...
5
Solved
I am using the following schema:
CREATE TABLE person (
person_name VARCHAR PRIMARY KEY
);
CREATE TABLE pet (
animal_name VARCHAR,
person_name VARCHAR REFERENCES person(person_name),
PRIMARY KE...
Linctus asked 29/5, 2014 at 2:29
14
Solved
PHP 8.1 has deprecated passing null as parameters to a lot of core functions. My main problem is with functions like htmlspecialchars(php) and trim(php), where null no longer is silently converted ...
Anthea asked 1/4, 2022 at 13:0
3
Solved
I want to fetch all columns of a table except of columns of type serial. The closest query to this problem I was able to come up with this one:
SELECT column_name FROM information_schema.columns
W...
Piezochemistry asked 2/4, 2014 at 16:54
19
Solved
I would like to know how to use NULL and an empty string at the same time in a WHERE clause in SQL Server. I need to find records that have either null values or an empty string. Thanks.
Mournful asked 27/3, 2013 at 15:50
10
Solved
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
2
Solved
I'm a total newbie and I don't get why this doesn't work, anyone knows what's happening?.
I'm following a tutorial and just to clarify, it is only a print(os.getenv("HOME"))
Chopine asked 1/2, 2022 at 17:24
22
Solved
I would like to prevent further processing on an object if it is null.
In the following code I check if the object is null by either:
if (!data.Equals(null))
and
if (data != null)
However, I...
Garofalo asked 20/6, 2011 at 21:40
5
Solved
There are many people who think that the concept of the special value null (as it is used in lanuages like C, Java, C#, Perl, Javascript, SQL etc.) is a bad idea. There are several questions about ...
Merce asked 23/1, 2015 at 9:0
3
Solved
How I can filter SQL results with != in PostgreSQL SQL query? Example
SELECT * FROM "A" WHERE "B" != 'C'
Working. But it's also filtered all record where "B" IS NULL....
Fibroblast asked 8/4, 2016 at 20:31
2
Solved
I want to make method that will check if the class instance is null or not.
Simply I know that i can use == null, but I want to know that is there any other way that can be implemented to check if...
19
Solved
Before calling a function of an object, I need to check if the object is null, to avoid throwing a NullPointerException.
What is the best way to go about this? I've considered these methods.
Whic...
Murchison asked 25/6, 2013 at 16:8
6
Solved
Consider the following Code :
import java.util.*;
class Employee {
String name;
public Employee(String nm) {
this.name=nm;
}
}
public class HashMapKeyNullValue {
Employee e1;
public...
Ancestor asked 19/9, 2014 at 11:19
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