identifier

问题 psql has a construct for passing named arguments: psql -v name='value' which can then be referenced inside a script: SELECT :name; which will give the result ?column? ---------- value (1 row) During development, I need to drop and recreate copies of the database fairly frequently, so I'm trying to automate the process. So I need to run a query that forcibly disconnects all users and then drops the database. But the database this operates on will vary, so the database name needs to be an

问题 Consider following program: #include <cstdio> int main() { int printf=9; std::printf("%d",printf); } Is it fine to use built in function name as an identifier in variable declaration? Is this well defined program? I mean is behaviour of above program well defined? I am curious to know whether the C++ standard allows to use standard function names as identifiers of variables 回答1: It's well-formed because neither std::printf nor ::printf (which may also have been declared by <cstdio> !) are

问题 Consider following program: #include <cstdio> int main() { int printf=9; std::printf("%d",printf); } Is it fine to use built in function name as an identifier in variable declaration? Is this well defined program? I mean is behaviour of above program well defined? I am curious to know whether the C++ standard allows to use standard function names as identifiers of variables 回答1: It's well-formed because neither std::printf nor ::printf (which may also have been declared by <cstdio> !) are

问题 Could you assist me with replacing an identifier value with a value from a dictionary. So the code looks like follow #string holds the value we want to output s = '${1}_p${guid}s_${2}' d = {1: 'bob', 2: '123abc', 3: 'CA', 4: 'smith' } I want to be able to replace ${1} with bob and ${2} with 123abc, I only want to change a value if the value inside ${} is just a number then, replace it with the value within the dictionary. output = 'bob_p${guid}s_123abc' I tried using template module, but it

问题 I wrote a SELECT performing a UNION and in each UNION part using some JOINs. The tables, which are joined have partly the same column identifiers. And if a "SELECT *" is performed, ORACLE decides to display the internal column names instead of the "real" column names. To show the effect I created two tables (with partly similar column identifiers, "TID" and "TNAME") and filled them with some data: create table table_one (tid number(10), tname varchar2(10), t2id number(10)); create table table

来源： https://stackoverflow.com/questions/30980053/quandl-stock-identifiers

问题 Currently logical ID of a resource is formed by concatenating the names of all of the constructs in the resource’s path and appending an eight-character MD5 hash. This produces garbage like VpcPrivateSubnet1DefaultRouteBE02A9ED and unfortunatelly makes it unable to query the resources by their logical id. Is there any way to control how logical ids are named? 回答1: In TypeScript the method you are looking for is overrideLogicalId . But you have to get the lower level CfnVpc construct first by

问题 Python allows unicode identifiers. I defined Xᵘ = 42 , expecting XU and Xᵤ to result in a NameError . But in reality, when I define Xᵘ , Python (silently?) turns Xᵘ into Xu , which strikes me as somewhat of an unpythonic thing to do. Why is this happening? >>> Xᵘ = 42 >>> print((Xu, Xᵘ, Xᵤ)) (42, 42, 42) 回答1: Python converts all identifiers to their NFKC normal form; from the Identifiers section of the reference documentation: All identifiers are converted into the normal form NFKC while

问题 I'm trying to find something I can use as a unique string/number for my script that is fixed in a machine and easily obtainable(cross-platform). I presume a machine would have a network card. I don't need it to be really unique, but the necessary is it should be fixed in a long run and as rare as possible. I know MAC can be changed and I'd probably make a warning about it in my script, however I don't expect anyone to change MAC each morning. What I came up with is uuid.getnode() , but in the

问题 I am attempting to create an abstracted getId method on my base Entity class in Symfony2 using Doctrine2 for a database where primary keys are named inconsistently across tables. When inspecting entity objects I see there is a private '_identifier' property that contains the information I am trying to retrieve but I am not sure how to properly access it. I'm assuming there is some simple Doctrine magic similar to: public function getId() { return $this->getIdentifier(); } But I haven't