Ruby has no pre/post increment/decrement operator. For instance, x++ or x– will fail to parse. More importantly, ++x or –x will do nothing! In fact, they behave as multiple unary prefix operators: -x == —x == —–x == …… To increment a number, simply write x += 1. Taken from “Things That Newcomers to Ruby … Read more
This depends entirely on the object i. += calls the __iadd__ method (if it exists — falling back on __add__ if it doesn’t exist) whereas + calls the __add__ method1 or the __radd__ method in a few cases2. From an API perspective, __iadd__ is supposed to be used for modifying mutable objects in place (returning … Read more
Not quite, although generally you can usually use some workaround on one of the forms [^abc], which is character by character not a or b or c, or negative lookahead: a(?!b), which is a not followed by b or negative lookbehind: (?<!a)b, which is b not preceeded by a
The C# language doesn’t have a power operator. However, the .NET Framework offers the Math.Pow method: Returns a specified number raised to the specified power. So your example would look like this: float Result, Number1, Number2; Number1 = 2; Number2 = 2; Result = Math.Pow(Number1, Number2);
The <=> (“Spaceship”) operator will offer combined comparison in that it will : Return 0 if values on either side are equal Return 1 if the value on the left is greater Return -1 if the value on the right is greater The rules used by the combined comparison operator are the same as the … Read more
In Ruby and Perl 6 this has been called “splat”, and I think most people from those communities will figure out what you mean if you call it that. The Python tutorial uses the phrase “unpacking argument lists”, which is long and descriptive. It is also referred to as iterable unpacking, or in the case … Read more
Use [A-Z]? to make the letter optional. {1} is redundant. (Of course you could also write [A-Z]{0,1} which would mean the same, but that’s what the ? is there for.) You could improve your regex to ^([0-9]{5})+\s+([A-Z]?)\s+([A-Z])([0-9]{3})([0-9]{3})([A-Z]{3})([A-Z]{3})\s+([A-Z])[0-9]{3}([0-9]{4})([0-9]{2})([0-9]{2}) And, since in most regex dialects, \d is the same as [0-9]: ^(\d{5})+\s+([A-Z]?)\s+([A-Z])(\d{3})(\d{3})([A-Z]{3})([A-Z]{3})\s+([A-Z])\d{3}(\d{4})(\d{2})(\d{2}) But: do you really need … Read more
r = +_; + tries to cast whatever _ is to a number. _ is only a variable name (not an operator), it could be a, foo etc. Example: +”1″ cast “1” to pure number 1. var _ = “1”; var r = +_; r is now 1, not “1”. Moreover, according to the MDN … Read more
MyClass.__contains__(self, item)
The % (modulo) operator yields the remainder from the division of the first argument by the second. The numeric arguments are first converted to a common type. A zero right argument raises the ZeroDivisionError exception. The arguments may be floating point numbers, e.g., 3.14%0.7 equals 0.34 (since 3.14 equals 4*0.7 + 0.34.) The modulo operator … Read more