Is there a way to expand a Python tuple into a function – as actual parameters? For example, here expand() does the magic: some_tuple = (1, “foo”, “bar”) def myfun(number, str1, str2): return (number * 2, str1 + str2, str2 + str1) myfun(expand(some_tuple)) # (2, “foobar”, “barfoo”) I know one could define myfun as myfun((a, … Read more
This question already has answers here: How to sort a list/tuple of lists/tuples by the element at a given index? (11 answers) Closed 4 years ago. I have a list of tuples that looks something like this: [(‘abc’, 121),(‘abc’, 231),(‘abc’, 148), (‘abc’,221)] I want to sort this list in ascending order by the integer value … Read more
This question already has answers here: What’s the difference between lists and tuples? (23 answers) Closed 7 years ago. In Python, when should you use lists and when tuples? Sometimes you don’t have a choice, for example if you have “hello %s you are %s years old” % x then x must be a tuple. … Read more
I’m trying to convert a list to a tuple. Most solutions on Google offer the following code: l = [4,5,6] tuple(l) However, the code results in an error message when I run it: TypeError: ‘tuple’ object is not callable How can I fix this problem? 7 s 7 It should work fine. Don’t use tuple, … Read more
Is there a good reason why there is no Pair<L,R> in Java? What would be the equivalent of this C++ construct? I would rather avoid reimplementing my own. It seems that 1.6 is providing something similar (AbstractMap.SimpleEntry<K,V>), but this looks quite convoluted. 36 s 36
I have some data either in a list of lists or a list of tuples, like this: data = [[1,2,3], [4,5,6], [7,8,9]] data = [(1,2,3), (4,5,6), (7,8,9)] And I want to sort by the 2nd element in the subset. Meaning, sorting by 2,5,8 where 2 is from (1,2,3), 5 is from (4,5,6). What is the … Read more
Reading the changes in Python 3.1, I found something… unexpected: The sys.version_info tuple is now a named tuple: I never heard about named tuples before, and I thought elements could either be indexed by numbers (like in tuples and lists) or by keys (like in dicts). I never expected they could be indexed both ways. … Read more
What’s the difference between tuples/lists and what are their advantages/disadvantages? 23 s 23 Apart from tuples being immutable there is also a semantic distinction that should guide their usage. Tuples are heterogeneous data structures (i.e., their entries have different meanings), while lists are homogeneous sequences. Tuples have structure, lists have order. Using this distinction makes … Read more
In a thread on comp.lang.java.help, Hunter Gratzner gives some arguments against the presence of a Pair construct in Java. The main argument is that a class Pair doesn’t convey any semantics about the relationship between the two values (how do you know what “first” and “second” mean ?). A better practice is to write a very simple class, like the one … Read more
I don’t think there is a general purpose tuple class in Java but a custom one might be as easy as the following: public class Tuple<X, Y> { public final X x; public final Y y; public Tuple(X x, Y y) { this.x = x; this.y = y; } } Of course, there are some … Read more
