functional-programming

问题 (This is inspired by another question marked as a duplicate. I think it is an interesting problem though, although perhaps there is an easy solution from combinatorics, about which I am very ignorant.) Problem For a vector of length n , where n mod 2 is zero, find all possible ways to partition all elements of the vector into pairs, without replacement, where order does not matter. For example, for a vector c(1,2,3,4) : list(c(1,2), c(3,4)) list(c(1,3), c(2,4)) list(c(1,4), c(2,3)) My

问题 I feel a little stupid for asking this, but I'm currently learning functional programming and completed an exercise on creating singly linked lists and it just got me thinking, is it even possible to create an immutable doubly linked list? Suppose the list A :: B, at time of construction, A needs to know about B, but B also needs to know about A. I've been doing this in Scala, so I'm not sure if it's specific to Scala, but I can't picture how that would work. I'm not looking for a substitute

问题 I have the following 3 case classes: case class Profile(name: String, age: Int, bankInfoData: BankInfoData, userUpdatedFields: Option[UserUpdatedFields]) case class BankInfoData(accountNumber: Int, bankAddress: String, bankNumber: Int, contactPerson: String, phoneNumber: Int, accountType: AccountType) case class UserUpdatedFields(contactPerson: String, phoneNumber: Int, accountType: AccountType) this is just enums, but i added anyway: sealed trait AccountType extends EnumEntry object

问题 How can I skip a function if the executing time too long. For example I have 3 functions : function A(){ Do something.. .. } function B(){ Do something.. .. } function C(){ Do something.. .. } A(); B(); C(); So for example for some reason function B have infinity loop inside, and keep running. How can I skip function B and go to function C if function B executing too long ? I tried this but seem not working : try { const setTimer = setTimeOut({ throw new Error("Time out!"); },500); B();

问题 How can I skip a function if the executing time too long. For example I have 3 functions : function A(){ Do something.. .. } function B(){ Do something.. .. } function C(){ Do something.. .. } A(); B(); C(); So for example for some reason function B have infinity loop inside, and keep running. How can I skip function B and go to function C if function B executing too long ? I tried this but seem not working : try { const setTimer = setTimeOut({ throw new Error("Time out!"); },500); B();

问题 What is the preferred way of reducing a list of UnaryOperators in Java 8 till they represent one UnaryOperator that I can call apply on? For example I have the following interface MyFilter extends UnaryOperator<MyObject>{}; public MyObject filterIt(List<MyFilter> filters,MyObject obj){ Optional<MyFilter> mf = filters .stream() .reduce( (f1,f2)->(MyFilter)f1.andThen(f2)); return mf.map(f->f.apply(obj)).orElse(obj); } But this code throws a ClassCastException at (MyFilter)f1.andThen(f2) . I

问题 What is the preferred way of reducing a list of UnaryOperators in Java 8 till they represent one UnaryOperator that I can call apply on? For example I have the following interface MyFilter extends UnaryOperator<MyObject>{}; public MyObject filterIt(List<MyFilter> filters,MyObject obj){ Optional<MyFilter> mf = filters .stream() .reduce( (f1,f2)->(MyFilter)f1.andThen(f2)); return mf.map(f->f.apply(obj)).orElse(obj); } But this code throws a ClassCastException at (MyFilter)f1.andThen(f2) . I

问题 What is the preferred way of reducing a list of UnaryOperators in Java 8 till they represent one UnaryOperator that I can call apply on? For example I have the following interface MyFilter extends UnaryOperator<MyObject>{}; public MyObject filterIt(List<MyFilter> filters,MyObject obj){ Optional<MyFilter> mf = filters .stream() .reduce( (f1,f2)->(MyFilter)f1.andThen(f2)); return mf.map(f->f.apply(obj)).orElse(obj); } But this code throws a ClassCastException at (MyFilter)f1.andThen(f2) . I

问题 Closed. This question does not meet Stack Overflow guidelines. It is not currently accepting answers. Want to improve this question? Update the question so it's on-topic for Stack Overflow. Closed 18 days ago . Improve this question With all the hype around functional programming, which are the best resources to getting started in functional programming [for a C# programmer]? I am not looking for C# 3.0 language improvements. 回答1: I think for a C# developer with .NET background, the best way

问题 Closed. This question does not meet Stack Overflow guidelines. It is not currently accepting answers. Want to improve this question? Update the question so it's on-topic for Stack Overflow. Closed 18 days ago . Improve this question With all the hype around functional programming, which are the best resources to getting started in functional programming [for a C# programmer]? I am not looking for C# 3.0 language improvements. 回答1: I think for a C# developer with .NET background, the best way