It’s called a Conditional (ternary) Operator. It’s essentially a condensed if-else. So this: var array = typeof objArray != ‘object’ ? JSON.parse(objArray) : objArray; …is the same as this: var array; if (typeof objArray != ‘object’) { array = JSON.parse(objArray); } else { array = objArray; }
For what it’s worth, Selectors 4 now explicitly instructs1 authors to use double colons for all pseudo-elements, including CSS1 and CSS2 pseudo-elements, going forward (emphasis mine): Because CSS Level 1 and CSS Level 2 conflated pseudo-elements and pseudo-classes by sharing a single-colon syntax for both, user agents must also accept the previous one-colon notation for … Read more
There’re differences among www, www/ and www/*. Basically from the documentation and my own tests, www find a match with a file or a directory, www/ only matches a directory, while www/* matches directories and files inside www. I’ll only discuss on the differences between www/ and www/* here, since the differences between www and … Read more
1e5 is a number expressed using scientific notation and it means 1 multiplied by 10 to the 5th power (the e meaning ‘exponent’) so 1e5 equals 1*100000and is equal to 100000, the three notations are interchangeable meaning the same.
To understand this you’ll first need to understand pointers and references. I’ll simply explain the type declaration syntax you’re asking about assuming you already know what pointers and references are. In C, it is said that ‘declaration follows use.’ That means the syntax for declaring a variable mimics using the variable: generally in a declaration … Read more
You are looking at the default str() formatting of floating point numbers, where scientific notation is used for sufficiently small or large numbers. You don’t need to convert this, the value itself is a proper float. If you need to display this in a different format, format it explicitly: >>> print(0.00001357) 1.357e-05 >>> print(format(0.00001357, ‘f’)) … Read more
Literals that start with 0x are hexadecimal integers. (base 16) The number 0x6400 is 25600. 6 * 16^3 + 4 * 16^2 = 25600 For an example including letters (also used in hexadecimal notation where A = 10, B = 11 … F = 15) The number 0x6BF0 is 27632. 6 * 16^3 + 11 … Read more
%w(foo bar) is a shortcut for [“foo”, “bar”]. Meaning it’s a notation to write an array of strings separated by spaces instead of commas and without quotes around them. You can find a list of ways of writing literals in zenspider’s quickref.
Despite the (formerly) accepted answer to this question, the bang is not in fact a member or collection access operator. It does one simple and specific thing: The bang operator provides late-bound access to the default member of an object, by passing the literal name following the bang operator as a string argument to that … Read more
This is useful to setting default values to function arguments, e.g.: function test (options) { options = options || {}; } If you call test without arguments, options will be initialized with an empty object. The Logical OR || operator will return its second operand if the first one is falsy. Falsy values are: 0, … Read more