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Why does typeof NaN return 'number'?
...eration
which return NaN:
Operations with a NaN as at least one operand
Indeterminate forms
The divisions 0/0, ∞/∞, ∞/−∞, −∞/∞, and −∞/−∞
The multiplications 0×∞ and 0×−∞
The power 1^∞
The additions ∞ + (−∞), (−∞) + ∞ and e...
Best practices for circular shift (rotate) operations in C++
Left and right shift operators (>) are already available in C++.
However, I couldn't find out how I could perform circular shift or rotate operations.
...
The difference between bracket [ ] and double bracket [[ ]] for accessing the elements of a list or
...different methods for accessing the elements of a list or data.frame: [] and [[]] .
12 Answers
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SQLite - UPSERT *not* INSERT or REPLACE
...no-op if the INSERT would violate a uniqueness constraint. UPSERT is not standard SQL. UPSERT in SQLite follows the syntax established by PostgreSQL.
GOOD but tendous: This will update 2 of the columns.
When ID=1 exists, the NAME will be unaffected.
When ID=1 does not exist, the name will be the...
Why does `a == b or c or d` always evaluate to True?
...
In many cases, Python looks and behaves like natural English, but this is one case where that abstraction fails. People can use context clues to determine that "Jon" and "Inbar" are objects joined to the verb "equals", but the Python interpreter is more...
What does 'COLLATE SQL_Latin1_General_CP1_CI_AS' do?
...akes the server treat strings using charset latin 1, basically ascii
CP1 stands for Code Page 1252
CI case insensitive comparisons so 'ABC' would equal 'abc'
AS accent sensitive, so 'ü' does not equal 'u'
P.S. For more detailed information be sure to read @solomon-rutzky's answer.
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&& (AND) and || (OR) in IF statements
...
No, it will not be evaluated. And this is very useful. For example, if you need to test whether a String is not null or empty, you can write:
if (str != null && !str.isEmpty()) {
doSomethingWith(str.charAt(0));
}
or, the other way around
if ...
Regex lookahead, lookbehind and atomic groups
...hat I can use them for.
Does somebody have examples so I can try to understand how they work?
3 Answers
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What characters do I need to escape in XML documents?
... to escape all five characters in text. However, the three characters ", ' and > needn't be escaped in text:
<?xml version="1.0"?>
<valid>"'></valid>
Attributes
The safe way is to escape all five characters in attributes. However, the > character needn't be escaped in ...
Why use the params keyword?
...ly doing to make the best choice.
– Allen Clark Copeland Jr
Nov 28 '15 at 22:15
2
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