keyword

问题 In python there is a pass keyword for defining an empty function, condition, loop, ... Is there something similar for Ruby? Python Example: def some_function(): # do nothing pass 回答1: No, there is no such thing in Ruby. If you want an empty block, method, module, class etc., just write an empty block: def some_method end That's it. In Python, every block is required to contain at least one statement, that's why you need a "fake" no-op statement. Ruby doesn't have statements, it only has

问题 I referred this question, in which some of the answers suggest that bool is an integral type (IDEs also treat it as a keyword). However, none of the answers suggest the information provided in cplusplus, which says that bool is a macro which is added through <cstdbool> (In that case, the compilers might be implicitly adding this header while compiling to allow bool ). Here is the g++ version of <stdbool.h>. So what exactly the bool is? A an integral type keyword or a macro? 回答1: In C, bool is

问题 I'm dreaming of a Python method with explicit keyword args: def func(a=None, b=None, c=None): for arg, val in magic_arg_dict.items(): # Where do I get the magic? print '%s: %s' % (arg, val) I want to get a dictionary of only those arguments the caller actually passed into the method, just like **kwargs , but I don't want the caller to be able to pass any old random args, unlike **kwargs . >>> func(b=2) b: 2 >>> func(a=3, c=5) a: 3 c: 5 So: is there such an incantation? In my case, I happen to

问题 Where can I find a list of all HQL keywords? 回答1: In the full Hibernate source download there's a grammar\hql.g file, which is the ANTLR language definition. You can view the latest version of this file from the official GitHub source repository here. In the tokens section you'll find all the tokens, including the keywords (they're the ones defined as strings, e.g. ALL="all" ). 回答2: Try this...not sure if it's complete or exact, but it may be, as it's a list of HQL tokens. 回答3: Here is the

问题 I would personally like to know the semantic difference between using Pass and None. I could not able to find any difference in execution. PS: I could not able to find any similar questions in SO. If you find one, please point it out. Thanks! 回答1: pass is a statement . As such it can be used everywhere a statement can be used to do nothing. None is an atom and as such an expression in its simplest form. It is also a keyword and a constant value for “nothing” (the only instance of the NoneType

问题 I tried to compile this: enum class conditional_operator { plus, or, not }; But apparently GCC (4.6) thinks these are special, while I can't find a standard that says they are (neither C++0x n3290 or C99 n2794). I'm compiling with g++ -pedantic -std=c++0x . Is this a compiler convenience? How do I turn it off? Shouldn't -std=c++0x turn this "feature" off? PS: Hmmm, apparently, MarkDown code formatting thinks so too... 回答1: Look at 2.5. They are alternative tokens for || and ! . There is a

问题 Clojure's system for creating an ad hoc hierarchy of keywords is familiar to most people who have spent a bit of time with the language. For example, most demos and presentations of the language include examples such as (derive ::child ::parent) and they go on to show how this can be used for multi-method dispatch. In all of the slides and presentations that I've seen, they use the global hierarchy. But it is possible to put keyword relationships in independent hierarchies, by using (derive h

问题 This question already has an answer here : Decryption/Encryption Python [closed] (1 answer) Closed 4 years ago . Trying to create a keyword cipher and Ive come across this,I know that it makes the string upper case and remove things like spaces commas and parentheses.I've tried removing it and my code doesnt work, I just want to know how I can remove this successfully from itertools import starmap,cycle def encrypt(message, key): # convert to uppercase. # strip out non-alpha characters.

问题 This question already has answers here : Closed 9 years ago . Possible Duplicates: Use of var keyword in C# Use of “var” type in variable declaration Hello everybody, "Var keywork it require explicitly type casting Avoid boxing and unboxing value types where possible." Is it advisable to use var keyword instead of explicit datatype? 回答1: From ReSharper Horizons blog: It induces better naming for local variables. When you read local variable declaration with explicit type, you have more

问题 After calling return a statement, it was brought out to me in the comments: return isn't a statement, it's the keyword that starts the return statement. What is the difference between a statement and a keyword that starts a statement ? 回答1: What's the difference between a sentence and a noun that starts a sentence? ;-) return is a keyword, which means it's one of a few basic terms (tokens) of the language. They are privileged, each reserved for a special purpose and having special meaning