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Re: Select x s.t. y>10

  • To: mathgroup at
  • Subject: [mg13988] Re: [mg13957] Select x s.t. y>10
  • From: Jurgen Tischer <jtischer at>
  • Date: Sat, 12 Sep 1998 16:59:12 -0400
  • References: <>
  • Sender: owner-wri-mathgroup at

Hi Jason,

In[1]:= li=Table[{n^2,n},{n,10}];

In[2]:= Cases[li,x_?(#[[2]]>5&):>(x[[1]]),1,1]

Out[2]= {36}


Jason Gill wrote:

> I came across what seems like it should be a simple little function, but
> could not come up with a clever way to implement it.  Generally, what I
> am trying to do is take a list of lists of length 2 ie a list of x,y
> coordinates, and Select x values based on some criterion for y.  For
> example I want to select the first x value for which the corresponding
> y is greater than 5.
> I can write a function using Position and Take etc. , but there must be
> a clever,and more efficient way to do this.  Any thoughts... Jason
> --
> Jason Gill
> IBM Microelectronics
> Essex Junction, VT 05452
> Phone   (802)769-3350
> Fax     (802)769-1220
> email:  jgill at
>            jasongil at

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