keyword

Counting the Number of keywords in a dictionary in python

由 风流意气都作罢 提交于 2019-11-26 18:55:59
问题 I have a list of words in a dictionary with the value = the repetition of the keyword but I only want a list of distinct words so I wanted to count the number of keywords. Is there a way to count the number of keywords or is there another way I should look for distinct words? 回答1: len(yourdict.keys()) or just len(yourdict) If you like to count unique words in the file, you could just use set and do like len(set(open(yourdictfile).read().split())) 回答2: The number of distinct words (i.e. count

Haskell: Where vs. Let

由 狂风中的少年 提交于 2019-11-26 18:47:27
问题 I am new to Haskell and I am very confused by Where vs. Let . They both seem to provide a similar purpose. I have read a few comparisons between Where vs. Let but I am having trouble discerning when to use each. Could someone please provide some context or perhaps a few examples that demonstrate when to use one over the other? Where vs. Let A where clause can only be defined at the level of a function definition. Usually, that is identical to the scope of let definition. The only difference

Difference between “this” and“super” keywords in Java

由 為{幸葍}努か 提交于 2019-11-26 18:38:56
What is the difference between the keywords this and super ? Both are used to access constructors of class right? Can any of you explain? Lets consider this situation class Animal { void eat() { System.out.println("animal : eat"); } } class Dog extends Animal { void eat() { System.out.println("dog : eat"); } void anotherEat() { super.eat(); } } public class Test { public static void main(String[] args) { Animal a = new Animal(); a.eat(); Dog d = new Dog(); d.eat(); d.anotherEat(); } } The output is going to be animal : eat dog : eat animal : eat The third line is printing "animal:eat" because

Is there a goto statement in Java?

由 痞子三分冷 提交于 2019-11-26 18:34:45
问题 I'm confused about this. Most of us have been told that there isn't any goto statement in Java. But I found that it is one of the keywords in Java. Where can it be used? If it can not be used, then why was it included in Java as a keyword? 回答1: The Java keyword list specifies the goto keyword, but it is marked as "not used". It was in the original JVM (see answer by @VitaliiFedorenko), but then removed. It was probably kept as a reserved keyword in case it were to be added to a later version

Python: SyntaxError: keyword can't be an expression

由 心不动则不痛 提交于 2019-11-26 17:48:42
问题 In a Python script I call a function from rpy2 , but I get this error: #using an R module res = DirichletReg.ddirichlet(np.asarray(my_values),alphas, log=False, sum.up=False) SyntaxError: keyword can't be an expression What exactly went wrong here? 回答1: sum.up is not a valid keyword argument name. Keyword arguments must be valid identifiers. You should look in the documentation of the library you are using how this argument really is called – maybe sum_up ? 回答2: I guess many of us who came to

How to get VS 2010 to recognize certain CUDA functions

由 点点圈 提交于 2019-11-26 17:48:31
问题 At the moment CUDA already recognizes a key CUDA C/C++ function such as cudaMalloc , cudaFree , cudaEventCreate , etc. It also recognizes certain types like dim3 and cudaEvent_t . However, it doesn't recognize other functions and types such as the texture template, the __syncthreads functions, or the atomicCAS function. Everything compiles just fine, but I'm tired of seeing red underlinings all over the place and I want to the see the example parameters displayed when you type in any

What are Virtual Methods?

由 蹲街弑〆低调 提交于 2019-11-26 17:28:09
问题 Why would you declare a method as "virtual". What is the benefit in using virtual? 回答1: The Virtual Modifier is used to mark that a method\property(ect) can be modified in a derived class by using the override modifier. Example: class A { public virtual void Foo() //DoStuff For A } class B : A { public override void Foo() //DoStuff For B //now call the base to do the stuff for A and B //if required base.Foo() } 回答2: Virtual allows an inheriting class to replace a method that the base class

What's the yield keyword in JavaScript?

由 ♀尐吖头ヾ 提交于 2019-11-26 16:58:53
I heard about a "yield" keyword in JavaScript, but I found very poor documentation about it. Can someone explain me (or recommend a site that explains) its usage and what it is used for? The MDN documentation is pretty good, IMO. The function containing the yield keyword is a generator. When you call it, its formal parameters are bound to actual arguments, but its body isn't actually evaluated. Instead, a generator-iterator is returned. Each call to the generator-iterator's next() method performs another pass through the iterative algorithm. Each step's value is the value specified by the

What does “self” mean in javascript?

由 亡梦爱人 提交于 2019-11-26 15:59:27
问题 I read here that " self Refers to the current window or form ". Self does not seem to refer to the current form in this case: <form><input type="text" onkeyup="alert(self.foo.value)" name="foo"></form> However in this case it works (referring to the window): <form><input type="text" onkeyup="alert(self.document.forms[0].foo.value)" name="foo"></form> So when would you use the self DOM property over just window ? 回答1: For all windows, the self and window properties of a window object are

Is there an ANSI SQL alternative to the MYSQL LIMIT keyword?

由 无人久伴 提交于 2019-11-26 15:22:57
Is there an ANSI SQL alternative to the MYSQL LIMIT keyword? The LIMIT keyword limits the number of rows returned by a SELECT e.g: SELECT * FROM People WHERE Age > 18 LIMIT 2; returns 2 rows. SELECT * FROM People WHERE Age > 18 LIMIT 10, 2; returns 2 rows after the first 10. jle this shows the different ways: -- DB2 select * from table fetch first 10 rows only -- Informix select first 10 * from table -- Microsoft SQL Server and Access select top 10 * from table -- MySQL and PostgreSQL select * from table limit 10 -- Oracle select * from (select * from table) where rownum <= 10 Not in SQL:1999.
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