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if A vs if A is not None:
...back to database stuff. There's a big difference between NULL and an empty string. An empty string typically says "there's a value here, and that value is nothing at all". NULL says "this value hasn't been entered."
In each of those cases, you'd want to use if A is None. You're checking for a speci...
Convert to binary and keep leading zeros in Python
...most compact and direct option.
If you are putting the result in a larger string, use an formatted string literal (3.6+) or use str.format() and put the second argument for the format() function after the colon of the placeholder {:..}:
>>> value = 14
>>> f'The produced output, i...
Dynamically creating keys in a JavaScript associative array
...
Assuming the text string actually does have the curly braces, you could more or less treat it as JSON.. replace the = sign with a : and you've got an object to eval..
– neonski
Dec 9 '08 at 3:15
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C++: What is the size of an object of an empty class?
...aligned on a word boundary (such as an integer). For example, if you place char x; int y; inside the class, my GCC clocks it at eight bytes (since the second int must be aligned in that implementation).
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PostgreSQL function for last inserted ID
...s some TRIGGER (or RULE) that, on insertion into persons table, makes some extra insertions in other tables... then LASTVAL will probably give us the wrong value. The problem can even happen with CURRVAL, if the extra insertions are done intto the same persons table (this is much less usual, but the...
How does this program work?
...oat is converted to double, as the prototype of printf is int printf(const char*, ...), from 6.5.2.2/7,
The ellipsis notation in a function prototype declarator causes argument type conversion to stop after the last declared parameter. The default argument promotions are performed on trailing ar...
Why don't Java's +=, -=, *=, /= compound assignment operators require casting?
...57
or
byte b = 100;
b /= 2.5;
System.out.println(b); // prints 40
or
char ch = '0';
ch *= 1.1;
System.out.println(ch); // prints '4'
or
char ch = 'A';
ch *= 1.5;
System.out.println(ch); // prints 'a'
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Best way to strip punctuation from a string
...om an efficiency perspective, you're not going to beat
s.translate(None, string.punctuation)
For higher versions of Python use the following code:
s.translate(str.maketrans('', '', string.punctuation))
It's performing raw string operations in C with a lookup table - there's not much that will...
Create an array with same element repeated multiple times
...ate (05/11/2019):
Another way, without using fill or from, that works for string of any length:
Array.apply(null, Array(3)).map(_ => 'abc') // ['abc', 'abc', 'abc']
Same as above answer. Adding for sake of completeness.
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reference assignment is atomic so why is Interlocked.Exchange(ref Object, Object) needed?
...ces:
"Reads and writes of the following
data types are atomic: bool, char,
byte, sbyte, short, ushort, uint, int,
float, and reference types."
So, you can write to the volatile reference without risk of getting a corrupted value.
You should of course be careful with how you decide which...