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3 de feb. de 2011 · 1. Most likely the '?' is the ternary operator. Its grammar is: RESULT = (COND) ? (STATEMEN IF TRUE) : (STATEMENT IF FALSE) It is a nice shorthand for the typical if-else statement:
7 de jun. de 2011 · The conditional (ternary) operator is the only JavaScript operator that takes three operands. This operator is frequently used as a shortcut for the if statement. condition ? expr1 : expr2. If condition is true, the operator returns the value of expr1; otherwise, it returns the value of expr2.
26 de abr. de 2012 · 323. This is the ternary conditional operator, which can be used anywhere, not just the print statement. It's sometimes just called "the ternary operator", but it's not the only ternary operator, just the most common one. Here's a good example from Wikipedia demonstrating how it works: A traditional if-else construct in C, Java and JavaScript ...
12 de sept. de 2021 · means: if a is true, return b, else return c. In this case, if f==r, return 1, else return 0. answered Apr 27, 2009 at 21:10. Joe. 42.4k20106127. 2. The question mark is the conditional operator. The code means that if f==r then 1 is returned, otherwise, return 0.
24 de oct. de 2011 · Negative lookaheads are used if you want to match something not followed by something else. The negative lookahead construct is the pair of parentheses, with the opening parenthesis followed by a question mark and an exclamation point. x(?!x2) example. Consider a word There; Now, by default, the RegEx e will find the third letter e in word ...
It means that the value type in question is a nullable type Nullable types are instances of the System.Nullable struct. A nullable type can represent the correct range of values for its underlying value type, plus an additional null value.
21 de mar. de 2017 · It's less than ideal, however, in that it is very verbose. This is where the question mark operator ? comes in. The above can be rewritten as: fn do_the_thing(i: i32) -> Result<i32, Error> { let i = halves_if_even(i)?; // use `i` } which is much more concise. What ? does here is equivalent to the match statement above with an addition. In short:
7 de mar. de 2013 · This specific character is usually the sign of an invalid (non-UTF-8) character showing up in an output (like a page) that has been declared to be UTF-8. It happens often when. a HTML or script source file is stored in the wrong encoding (e.g. Windows-1252 instead of UTF-8) - make sure it's saved as a UTF-8 file.
25 de mar. de 2017 · 10.8k35154. 41. Not exactly. Question mark means "optional". So it's a shorthand for "parameter: type | undefined = undefined".. – mcoolive. CommentedMay 7, 2020 at 17:50. 13. Actually, it does not default to undefined, but rather to nonexistence.
778. It's the null conditional operator. It basically means: "Evaluate the first operand; if that's null, stop, with a result of null. Otherwise, evaluate the second operand (as a member access of the first operand)." In your example, the point is that if a is null, then a?.PropertyOfA will evaluate to null rather than throwing an exception ...
