The first two expressions both parse as tuples: (0, 0) == 0 (which is False), followed by 0 0, followed by 0 == (0, 0) (which is still False that way around). The expressions are split that way because of the relative precedence of the comma separator compared to the equality operator: Python sees a … Read more
If you are on .NET 4.0 use a Tuple: lookup = new Dictionary<Tuple<TypeA, TypeB, TypeC>, string>(); If not you can define a Tuple and use that as the key. The Tuple needs to override GetHashCode, Equals and IEquatable: struct Tuple<T, U, W> : IEquatable<Tuple<T,U,W>> { readonly T first; readonly U second; readonly W third; public … Read more
While the answer by octavioccl works, it’s better to first project the query result into anonymous type, and then switch to enumerable and convert it to tuple. This way your query will retrieve from the data base only the fields needed. codes = codesRepo.SearchFor(predicate) .Select(c => new { c.Id, c.Flag }) .AsEnumerable() .Select(c => new … Read more
A cynical answer is that many people program in C++, but do not understand and/or use the higher level functionality. Sometimes it is because they are not allowed, but many simply do not try (or even understand). As a non-boost example: how many folks use functionality found in <algorithm>? In other words, many C++ programmers … Read more
Use max(): Using itemgetter(): In [53]: lis=[(101, 153), (255, 827), (361, 961)] In [81]: from operator import itemgetter In [82]: max(lis,key=itemgetter(1))[0] #faster solution Out[82]: 361 using lambda: In [54]: max(lis,key=lambda item:item[1]) Out[54]: (361, 961) In [55]: max(lis,key=lambda item:item[1])[0] Out[55]: 361 timeit comparison: In [30]: %timeit max(lis,key=itemgetter(1)) 1000 loops, best of 3: 232 us per … Read more
Javascript 1.7 added destructuring assignment which allows you to do essentially what you are after. function getTuple(){ return [“Bob”, 24]; } var [a, b] = getTuple(); // a === “bob” , b === 24 are both true
This msdn article explains it very well with examples, “A tuple is a data structure that has a specific number and sequence of elements“. Tuples are commonly used in four ways: To represent a single set of data. For example, a tuple can represent a database record, and its components can represent individual fields of … Read more
There’s a good article on the topic in the Python wiki: Why Lists Can’t Be Dictionary Keys. As explained there: What would go wrong if you tried to use lists as keys, with the hash as, say, their memory location? It can be done without really breaking any of the requirements, but it leads to … Read more
That is a very strange way to organize things. If you stored in a dictionary, this is easy: # This example should work in any version of Python. # urls_d will contain URL keys, with counts as values, like: {‘http://www.google.fr/’ : 1 } urls_d = {} for url in list_of_urls: if not url in urls_d: … Read more
Use str.join: >>> tup = (‘a’, ‘b’, ‘c’, ‘d’, ‘g’, ‘x’, ‘r’, ‘e’) >>> ”.join(tup) ‘abcdgxre’ >>> >>> help(str.join) Help on method_descriptor: join(…) S.join(iterable) -> str Return a string which is the concatenation of the strings in the iterable. The separator between elements is S. >>>