Re: how to test where a list contains constant(s) or not
- To: mathgroup at smc.vnet.net
- Subject: [mg91984] Re: how to test where a list contains constant(s) or not
- From: Szabolcs Horvát <szhorvat at gmail.com>
- Date: Tue, 16 Sep 2008 19:22:20 -0400 (EDT)
- Organization: University of Bergen
- References: <gal3iu$e0a$1@smc.vnet.net>
Aya wrote:
> case1: { a, b, c, Pi } gives true because of Pi
> case2: { a, b, c, 0.0001} gives true because of 0.0001
> case3: { a, b, c, 2 + Pi I } gives ture becase of 2 + Pi I
> case4: { a, b, c} gives false
>
> is this function right ?
>
Most of what you've written is completely redundant.
> ComplexQ[z_] := NumericQ[ z ] || ( NumericQ[ z ] && SameQ[ Head[ z ],
> Complex] )
This ComplexQ function is completely equivalent to NumericQ. p || (p &&
q) is just p, right?
> IsConstantsIn[ lstList_ ] :=
> Module[ { intLength },
> intLength = Length@Select[ lstList, ComplexQ[ # ]& ];
One could just use ComplexQ instead of ComplexQ[#]&.
> If[ intLength > 0, Return[ True ], Return[ False ] ];
> Return[ False ];
> ]
>
You almost never need to use Return in Mathematica. The above two lines
are equivalent to the simple expression intLength > 0 in this context.
With all these simplifications your function becomes
f[lst_List] := Length@Select[lst, NumericQ] > 0
But the following approach is simpler and more efficient:
g[lst_List] := MemberQ[lst, _?NumericQ]