elegant way to subtract a number of every list element

Question

I recently ran into following problem: Given a list of numbers, I want to subtract a constant from every entry of this list. The natural but wrong thing to do is

map (-3) [5,6,7]

Here the - is not interpreted a binary function but as an unary negation operator.

I found following workarounds:

map (+(-3)) [5,6,7]
map ((+)(-3)) [5,6,7]
map (flip (-) 3) [5,6,7]

Question : Is there a more elegant way to do this that avoids this unnecessary pile of parenthesis?

score 3 · Accepted Answer · answered Dec 16 '16 at 09:58

3

Nope, sorry. You have the subtract function, but it's not shorter.

Prelude> map (subtract 3) [3,4,5]
[0,1,2]

answered Dec 16 '16 at 09:58

Filip Haglund

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I somehow have the feeling that you magically smelled that I was coming from PPCG :D – flawr Dec 16 '16 at 10:01
@flawr might have seen you around on PPCG :) – Filip Haglund Dec 16 '16 at 10:03

elegant way to subtract a number of every list element

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