Difference Between ? and ! in Swift Language?
99447
What is the difference between String? and String! (two ways of creating an optional variable)?
113601
What is the difference between .*? and .* regular expressions?
111925
What's the difference between !, %, and @ in replacement tokens?
15469
Difference between ! vs !! vs * in /etc/shadow
23756
Why does one often see "null != variable" instead of "variable != null" in C#?
46477
How to understand nil vs. empty vs. blank in Ruby
31316
Expression Versus Statement
51160
What does !! mean in ruby?
135424
Difference between "or" and || in Ruby?
20348
What does the '!' really do when it's added to an ex command (:wq! | :w! | :q! )?
58423
What does !! (double exclamation point) mean?
28734
Why is "a" != "a" in C?
121601
Difference between the use of "a" and "any" in these examples?
32293
What's the difference between if(!$variable) and if(isset($variable))?
80539
Why would you use Expression> rather than Func?
12091
Are if else statement equivalent to logical and && or || and where should I prefer one over the other?
10728
#ifdef replacement in the Swift language