set

问题 Is there a way to create a set from a string of separated values in MySQL? For example: 'the,quick,brown,fox' => 'the','quick','brown','fox' A sort of inverse EXPORT_SET without the bit fiddeling. Regards 回答1: If you're trying to use the set in an IN statement, instead of splitting the string, you could do a comparison like: SELECT * FROM `table` WHERE 'the,quick,brown,fox' REGEXP CONCAT('(^|,)','word','(,|$)'); I'm not sure how efficient this would be if your dataset is large, but it might

问题 I've been searching for a way to have users set my program as the default to open files for awhile and found nothing. I have a program that is supposed to be universal for Mac, Windows and Linux, so I don't want to use a method that only works with one OS. So how can I give users the ability to set a Java app as the default file opener? Would I use the Desktop class? 回答1: No Java does not support this. You would have to write a small app for every OS that you want to support in its native

问题 People of stackoverflow. I am new to c# and this is the first time I have not been able to find an answer to one of my elementary questions. Who can help me?!I am trying to define set logic for a public instance field. This runs flawlessly, public string Headline {get; set;} This results in stack overflow public string Headline { get { return Headline; } set { Headline = value; } } 回答1: You're calling the getter and setter recursively (calling themselves infinitely), inevitably causing a

问题 What's the most idiomatic way to convert a set of integers into a set of ranges? E.g. given the set {0, 1, 2, 3, 4, 7, 8, 9, 11} I want to get { {0,4}, {7,9}, {11,11} }. Let's say we are converting from std::set<int> into std::vector<std::pair<int, int>> . I treat Ranges as inclusive on both sides, since it's more convenient in my case, but I can work with open-ended ranges too if necessary. I've written the following function, but I feel like reinventing the wheel. Please tell maybe there's

问题 In Java I like to use the Boolean value returned by an "add to the set" operation to test whether the element was already present in the set: if (set.add("x")) { print "x was not yet in the set"; } My question is, is there something as convenient in Python? I tried z = set() if (z.add(y)): print something But it does not print anything. Am I missing something? Thx! 回答1: In Python, the set.add() method does not return anything. You have to use the not in operator: z = set() if y not in z: # If

问题 In Java I like to use the Boolean value returned by an "add to the set" operation to test whether the element was already present in the set: if (set.add("x")) { print "x was not yet in the set"; } My question is, is there something as convenient in Python? I tried z = set() if (z.add(y)): print something But it does not print anything. Am I missing something? Thx! 回答1: In Python, the set.add() method does not return anything. You have to use the not in operator: z = set() if y not in z: # If

问题 Here is my code: i used set() and it return [3, 14, 6] items = [3, 6, 3, 3, 14] set(items) >>> set([3,14,6]) My question is how is the set function organizes it values output. If we think about this, 3 is the first number and 6 is the second on the list, so should it output [3,6,14] instead? 回答1: Sets are unordered. From the documentation: Being an unordered collection, sets do not record element position or order of insertion. Like dictionaries, the ordering is based on the hashes of the

问题 I am trying to create a custom setter method for my property. Below is my code. I am getting a waring Attempting to access 'myProperty' within its own getter var myProperty:String{ get { if CONDITION1 { return CONDITION1_STRING }else if CONDITION2 { return CONDITION2_STRING }else{ return myProperty } } set{ } } What is wrong in my code. can any body help to fix this. 回答1: Create a backing ivar and add a custom setter: private _myProperty: String var myProperty: String { get { if CONDITION1 {

问题 I am trying to create a custom setter method for my property. Below is my code. I am getting a waring Attempting to access 'myProperty' within its own getter var myProperty:String{ get { if CONDITION1 { return CONDITION1_STRING }else if CONDITION2 { return CONDITION2_STRING }else{ return myProperty } } set{ } } What is wrong in my code. can any body help to fix this. 回答1: Create a backing ivar and add a custom setter: private _myProperty: String var myProperty: String { get { if CONDITION1 {

问题 I have some list of data, for example some_data = [1, 2, 4, 1, 6, 23, 3, 56, 6, 2, 3, 5, 6, 32, 2, 12, 5, 3, 2] and i want to get unique values with fixed length(i don't care which i will get) and i also want it to be set object. I know that i can do set from some_data then make it list , crop it and then make it set again. set(list(set(some_data))[:5]) # don't look so friendly I understand that i don't have __getitem__ method in set which wouldn't make the whole slice thing possible, but if