This has nothing to do with functools.partial, really. You are essentially calling your function like this: f(1, x=3) Python first fulfils the positional arguments, and your first argument is x. Then the keyword arguments are applied, and you again supplied x. functools.partial() has no means to detect that you already supplied the first positional argument … Read more
No According to the documentation, partial cannot do this (emphasis my own): partial.args The leftmost positional arguments that will be prepended to the positional arguments You could always just “fix” pow to have keyword args: _pow = pow pow = lambda x, y: _pow(x, y)
functools.partial returns a callable wrapping a function with some or all of the arguments frozen. import sys import functools print_hello = functools.partial(sys.stdout.write, “Hello world\n”) print_hello() Hello world The above usage is equivalent to the following lambda. print_hello = lambda *a, **kw: sys.stdout.write(“Hello world\n”, *a, **kw)
.bind is a normal function, so you can call .apply on it. All you have to do is pass the original function as the first param and the desired THIS variable as the first item in the array of arguments: bound = db.find.bind.apply(db.find, [null].concat(arguments)); // ^—–^ ^—–^ THIS Whether that can be considered cleaner or … Read more
You are here confusing two concepts. A partially applied function [haskell-wiki] with a partial function [haskell-wiki]. A partially applied function is: Partial application in Haskell involves passing less than the full number of arguments to a function that takes multiple arguments. whereas a partial function indeed is a non-total function: A partial function is a … Read more
functools.partial returns a callable wrapping a function with some or all of the arguments frozen. import sys import functools print_hello = functools.partial(sys.stdout.write, “Hello world\n”) print_hello() Hello world The above usage is equivalent to the following lambda. print_hello = lambda *a, **kw: sys.stdout.write(“Hello world\n”, *a, **kw)
It makes you able to do e.g.: scala> def foo(as: Int*)(bs: Int*)(cs: Int*) = as.sum * bs.sum * cs.sum foo: (as: Int*)(bs: Int*)(cs: Int*)Int scala> foo(1, 2, 3)(4, 5, 6, 7, 9)(10, 11) res7: Int = 3906
Strictly speaking, this is not a curried function, but a method with multiple argument lists, although admittedly it looks like a function. As you said, the multiple arguments lists allow the method to be used in the place of a partially applied function. (Sorry for the generally silly examples I use) object NonCurr { def … Read more
For languages that support currying and partial-application easily, there is one compelling series of arguments, originally from Chris Okasaki: Put the data structure as the last argument Why? You can then compose operations on the data nicely. E.g. insert 1 $ insert 2 $ insert 3 $ s. This also helps for functions on state. … Read more
Java 8 (released March 18th 2014) does support currying. The example Java code posted in the answer by missingfaktor can be rewritten as: import java.util.function.*; import static java.lang.System.out; // Tested with JDK 1.8.0-ea-b75 public class CurryingAndPartialFunctionApplication { public static void main(String[] args) { IntBinaryOperator simpleAdd = (a, b) -> a + b; IntFunction<IntUnaryOperator> curriedAdd = … Read more