There is technically no reason to accept other sequence types, no. The source code roughly does this: if isinstance(prefix, tuple): for substring in prefix: if not isinstance(substring, str): raise TypeError(…) return tailmatch(…) elif not isinstance(prefix, str): raise TypeError(…) return tailmatch(…) (where tailmatch(…) does the actual matching work). So yes, any iterable would do for that … Read more
You’d have to ask the BCL designers to be certain, but I suspect that since there is a 1-tuples in the real world, the .NET framework authors wanted to provide equivalent symmetry in their implementation. Tuples are the .NET implementation of what you’d consider the mathematical concept of a tuple. Now since you’re asking for … Read more
use zip if you need both >>> r=(1,’one’),(2,’two’),(3,’three’) >>> zip(*r) [(1, 2, 3), (‘one’, ‘two’, ‘three’)]
You can shorten it to: void test( Action<ValueTuple<string, int>> fn) { fn((“hello”, 10)); } test(((string s, int i) t) => { Console.WriteLine(t.s); Console.WriteLine(t.i); }); Hopefully, one day we might be able to splat the parameters from a tuple to the method invocation: void test(Action<ValueTuple<string, int>> fn) { fn(@(“hello”, 10)); // <– made up syntax } … Read more
From C++0x draft: [ Note: The reason get is a nonmember function is that if this functionality had been provided as a member function, code where the type depended on a template parameter would have required using the template keyword. — end note ] This can be illustrated with this code: template <typename T> struct … Read more
The definition for Dictionary is struct Dictionary<KeyType : Hashable, ValueType> : …, i.e. the type of the key must conform to the protocol Hashable. But the language guide tells us that protocols can be adopted by classes, structs and enums, i.e. not by tuples. Therefore, tuples cannot be used as Dictionary keys. A workaround would … Read more
Tuples are great if you control both creating and using them – you can maintain context, which is essential to understanding them. On a public API, however, they are less effective. The consumer (not you) has to either guess or look up documentation, especially for things like Tuple<int, int>. I would use them for private/internal … Read more
You could create a dictionary from your elements, with whatever you wanted to be unique as the key, then extracting the values. This works for anything where the ‘unique’ sub-element is hashable. Integers are hashable: def unique_by_key(elements, key=None): if key is None: # no key: the whole element must be unique key = lambda e: … Read more
plt.plot returns a list of the Line2D objects plotted, even if you plot only one line. That comma is unpacking the single value into line. ex a, b = [1, 2] a, = [1, ]
You could use map: map (lambda t: (t[1], t[0]), mylist) Or list comprehension: [(t[1], t[0]) for t in mylist] List comprehensions are preferred and supposedly much faster than map when lambda is needed, however note that list comprehension has a strict evaluation, that is it will be evaluated as soon as it gets bound to … Read more