set

问题 This question already has answers here : Best way to find the intersection of multiple sets? (5 answers) Closed 12 days ago . list(set(a[0]) & set(a[1]) & set(a[2]) & set(a[3]) & set(a[4])) Does anyone know how to write this in a way such that we dont need to know apriori how many lists we will be given? (ie 5 not hard coded in)? Each a is a list of varying size. 回答1: As long as you have at least one set, you can do this: list(set(a[0]).intersection(*a[1:])) If there might be no sets, you

问题 Assuming I am not running server side scripting of any kind, how can I set and get a cookie from within VBA code? 回答1: I saw a posting about this that might help for setting the cookie: link text Here is his code snippet: Sub test() Dim w As New WinHttp.WinHttpRequest Dim t As String, qs As String qs = "this=that&more=less" w.Open "POST", "http://www.comparity.net/perl/form.pl?a=b", False w.setRequestHeader "Cookie", "one=foo" w.setRequestHeader "Cookie", "two=bar" w.send qs t = w

问题 Suppose I have a list of sets and I want to get the union over all sets in that list. Is there any way to do this using a generator expression? In other words, how can I create the union over all sets in that list directly as a frozenset ? 回答1: Just use the .union() method. >>> l = [set([1,2,3]), set([4,5,6]), set([1,4,9])] >>> frozenset().union(*l) frozenset([1, 2, 3, 4, 5, 6, 9]) This works for any iterable of iterables. 回答2: I assume that what you're trying to avoid is the intermediate

问题 I have a number of lists of lists stored in a dictionary. I want to find the intersection of the sub-lists (i.e. intersection of dict[i][j]) for all keys of the dictionary . ) For example, if the dictionary stored sets of tuples instead, I could use the code: set.intersection(*[index[key] for key in all_keys]) What is an efficient way to do this? One way I tried was to first convert each list of lists into a set of tuples and then taking the intersection of those, but this is rather clunky.

问题 Message is a class I made. I have a set of them in the main function that I pass to messageTimeOut (and some other functions). In messageTimeOut using an itorator I am looping through them and accessing different member functions. However, I can only access const member functions of the Message pointed to by the iterator. If I try to access non const member functions I get the error: “In function 'void messageTimeOut(threadParameters*)': main.cpp:74:33: error: passing 'const Message' as 'this

问题 Why was Python's filter designed such that if you run filter(my_predicate, some_set) , I get back a list object return than a set object? Are there practical cases where you would not want the result to be a set ...? 回答1: You can do a set comprehension. {my_predicate(x) for x in some_set} # mapping {x for x in some_set if my_predicate(x)} # filtering such as In [1]: s = set([1,2,3]) In [2]: {x%2 for x in s} Out[2]: {0, 1} Many of the "functional" functions in Python 2 are standardized on

问题 Why was Python's filter designed such that if you run filter(my_predicate, some_set) , I get back a list object return than a set object? Are there practical cases where you would not want the result to be a set ...? 回答1: You can do a set comprehension. {my_predicate(x) for x in some_set} # mapping {x for x in some_set if my_predicate(x)} # filtering such as In [1]: s = set([1,2,3]) In [2]: {x%2 for x in s} Out[2]: {0, 1} Many of the "functional" functions in Python 2 are standardized on

问题 I am creating a program that uses a grammar and see if this grammar is LL (1). I want to use the module Set, but I have no idea how to proceed, of course, the type of the elements of the set will char, can you help? 回答1: This answer assumes that you already know how to determine if a grammar is LL (1), and are merely looking for help on the specific usage of the Objective Caml Set module. The standard library Set provides a functor that lets you construct your own set module, adapted for your

问题 I have a struct with some members and I have an implemented operator== for it. Is it safe to implement the operator< with the help of operator==? I want to use this struct in a set, and I want to check that this struct is unique. struct Data { std::string str1; std::string str2; std::string str3; std::string str4; bool operator==(const Data& rhs) { if (str1 == rhs.str1 && str2 == rhs.str2 && str3 == rhs.str3 && str4 == rhs.str4 ) return true; else return false; } // Is this ok?? bool operator

问题 I have like a log.txt file which contains: MyName My batch: @echo off set name= [log.txt] in the [log.txt] part, it should read 'MyName' from the log.txt file, to set it as 'name'. How? 回答1: You can also use set /p name=<log.txt which might be considered shorter and a little less ugly. 回答2: In cmd.exe, there's only this ugly way: @echo off for /f "usebackq tokens=* delims=" %%i in ("log.txt") do ( set name=%%i ) 来源： https://stackoverflow.com/questions/932552/set-log-txt-in-batch