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What is a NullReferenceException, and how do I fix it?
...ess members (such as methods) through a null reference. The simplest case:
string foo = null;
foo.ToUpper();
This will throw a NullReferenceException at the second line because you can't call the instance method ToUpper() on a string reference pointing to null.
Debugging
How do you find the source ...
How to delete from a text file, all lines that contain a specific string?
...would I use sed to delete all lines in a text file that contain a specific string?
17 Answers
...
Find document with array that contains a specific value
...
As favouriteFoods is a simple array of strings, you can just query that field directly:
PersonModel.find({ favouriteFoods: "sushi" }, ...);
But I'd also recommend making the string array explicit in your schema:
person = {
name : String,
favouriteFoods...
How do I make the method return type generic?
... define callFriend this way:
public <T extends Animal> T callFriend(String name, Class<T> type) {
return type.cast(friends.get(name));
}
Then call it as such:
jerry.callFriend("spike", Dog.class).bark();
jerry.callFriend("quacker", Duck.class).quack();
This code has the benefit...
sprintf like functionality in Python
I would like to create a string buffer to do lots of processing, format and finally write the buffer in a text file using a C-style sprintf functionality in Python. Because of conditional statements, I can’t write them directly to the file.
...
How to format a java.sql Timestamp for displaying?
How do I formate a java.sql Timestamp to my liking ? ( to a string, for display purposes)
7 Answers
...
ES6 class variable alternatives
...bles in ESNext, check this example:
class Foo {
bar = 2
static iha = 'string'
}
const foo = new Foo();
console.log(foo.bar, foo.iha, Foo.bar, Foo.iha);
// 2, undefined, undefined, 'string'
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Process.start: how to get the output?
...ead from it:
proc.Start();
while (!proc.StandardOutput.EndOfStream)
{
string line = proc.StandardOutput.ReadLine();
// do something with line
}
You can use int.Parse() or int.TryParse() to convert the strings to numeric values. You may have to do some string manipulation first if there ar...
How to insert a SQLite record with a datetime set to 'now' in Android application?
...ravitamada', 'datetime()'");
Method 3
Using java Date functions
private String getDateTime() {
SimpleDateFormat dateFormat = new SimpleDateFormat(
"yyyy-MM-dd HH:mm:ss", Locale.getDefault());
Date date = new Date();
return dateFormat.format(date);
}
Conten...
Get number of digits with JavaScript
...n't need parenthesis ():
function getlength(number) {
return number.toString().length;
}
UPDATE: As discussed in the comments, the above example won't work for float numbers. To make it working we can either get rid of a period with String(number).replace('.', '').length, or count the digits ...