On Jun 17, 2010, at 12:02 PM, Martin Drautzburg wrote:

The standard map function applies a single function to a list of arguments. But what if I want to apply a list of functions to a single argument. I can of course write such a function, but I wonder if there is a standard way of doing this,

Use Control.Applicative, and the <*> operator. Something like [f, g, h, i, j] <*> pure x (which equals [f x, g x, h x, i x , j x])

Related to that is the problem, that the function in map may require more than one argument, so I need to apply it partially to some value(s) first. But what if I want to fix its second and third argument and not its first argument? Can flip help?

I think the <$> operator can help here. Also, don't forget plain old lambda abstraction to abstract over a free variable.

Martin Drautzburg wrote:

Hello all

The standard map function applies a single function to a list of arguments. But what if I want to apply a list of functions to a single argument. I can of course write such a function, but I wonder if there is a standard way of doing this,

The magical incantation you seek is "map ($ x) [fn1, fn2, fn3]". Remember that "$" is a function like any other, and can be curried.

listFs = [f1, f2, f3] map ($ x) listFs -- same as [f1 x, f2 x, f3 x] f x y z = ... map (\x -> f x u v) xs On 17 Jun 2010, at 23:02, Martin Drautzburg wrote:

Hello all

The standard map function applies a single function to a list of arguments. But what if I want to apply a list of functions to a single argument. I can of course write such a function, but I wonder if there is a standard way of doing this,

Related to that is the problem, that the function in map may require more than one argument, so I need to apply it partially to some value(s) first. But what if I want to fix its second and third argument and not its first argument? Can flip help?

Thanks

-- Martin _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe

map (\function -> function argument) functions map ($ argument) functions map (\firstArgument -> function firstArgument secondArgument thirdArgument) xs On 17.06.10 22:02, Martin Drautzburg wrote:

Hello all

The standard map function applies a single function to a list of arguments. But what if I want to apply a list of functions to a single argument. I can of course write such a function, but I wonder if there is a standard way of doing this,

Related to that is the problem, that the function in map may require more than one argument, so I need to apply it partially to some value(s) first. But what if I want to fix its second and third argument and not its first argument? Can flip help

-- Best regards, Roman Beslik.