Re: a simple product, but with "i = 1...n AND i != x"
- To: mathgroup at smc.vnet.net
- Subject: [mg70257] Re: a simple product, but with "i = 1...n AND i != x"
- From: "Ray Koopman" <koopman at sfu.ca>
- Date: Tue, 10 Oct 2006 06:12:08 -0400 (EDT)
- References: <egcok5$je2$1@smc.vnet.net>
xarnaudx at gmail.com wrote:
> hi,
> i would like to make a function like
> f[x_] := Product[x - i, {i, 1, n} AND i != x}
>
> obviously, the end of the expression is syntactically incorrect. But
> how to rewrite this product correctly?
> thanks
There are several possibilities. Here are three:
Times@@(x - Range@n /. 0 -> 1)
Times@@(x - DeleteCases[Range@n, x])
Product[x - i + Boole[x == i], {i, n}]