2008年12月11日 · In JavaScript, the "===" operator should be used for strict equality comparison, while "==" is used for abstract equality comparison.

I have always used || (two pipes) in OR expressions, both in C# and PHP. Occasionally I see a single pipe used: |. What is the difference between those two usages? Are there any caveats when using ...

2017年7月25日 · “&”这个符号按照以下图片所示一笔手写成。 &是逻辑语言，逻辑上表示两者属于缺一不可的关系，还可以表示一个人和另外一个人之意，与and同义。如A&B，表示A与B,A和B,A*B。 “ampersand” 这个词1837年被第一次加到字典中，它是 “and, per se and” 的连读音。& 包含在任何罗马字体中，在现代语文中被 ...

2010年5月9日 · If we want to look for a div that contains both this AND that in their value attribute, we can simply connect both conditions, like so: div[value*="this"][value*="that"] In case we want the div that contains either this OR that, you can use a comma between both conditions, like so: div[value*="this"], div[value*="that"] Note: You can use as much conditions as you like. This is …

Original Question && is notoriously hard to search for on Google Search, but the best I've found is this article which says to use -and. Unfortunately it doesn't give any more information, and I can't find out what I'm supposed to do with -and (again, a notoriously hard thing to search for). The context I'm trying to use it in is "execute cmd1, and if successful, execute cmd2", basically this ...

2016年3月22日 · 这个用在and和or前面、有三者及以上并列时的逗号叫做 serial comma，或者series comma、 Oxford comma 、 Harvard comma。 基本原则 简单来说，加不加这个逗号，主要是习惯和地域问题。 绝大部分的美国出版写作规范（style）都会要求加上这个逗号；而大部分的英国出版写作规范则反对使用serial comma或者认为它可 ...

Java has 5 different boolean compare operators: &, &&, |, ||, ^ & and && are "and" operators, | and || "or" operators, ^ is "xor" The single ones will check every parameter, regardless of the values, before checking the values of the parameters. The double ones will first check the left parameter and its value and if true (||) or false (&&) leave the second one untouched. Sound …

2010年3月21日 · There is no bitwise negation in Python (just the bitwise inverse operator ~ - but that is not equivalent to not). See also 6.6. Unary arithmetic and bitwise/binary operations and 6.7. Binary arithmetic operations. The logical operators (like in many other languages) have the advantage that these are short-circuited. That means if the first operand already defines the …

2009年9月4日 · Be warned! & and | do short-circuit, sometimes. Quoth the documentation: "When you use the element-wise & and | operators in the context of an if or while loop expression (and only in that context), they use short-circuiting to evaluate expressions." This bizarre behavior is peculiar to MATLAB and is not shared by any other language that uses these operators.

2011年11月30日 · What everybody answered is correct. I would add they are useless. /^.*(…).*$/ is exactly the same as /(…)/.