Re: simple question about removing elements from a table

• To: mathgroup at smc.vnet.net
• Subject: [mg122383] Re: simple question about removing elements from a table
• From: Tomas Garza <tgarza10 at msn.com>
• Date: Thu, 27 Oct 2011 06:29:29 -0400 (EDT)
• Delivered-to: l-mathgroup@mail-archive0.wolfram.com
• References: <201110262137.RAA29967@smc.vnet.net>

```Try
In[1]:= data = {{-0.5, 0.0321787}, {-0.489, 0.0321691}, {-0.478,     0.032211}, {-0.467, 0.0321723}, {-0.456, 0.0322448}, {-0.444,     0.0321498}, {-0.433, 0.032132}, {-0.422, 0.0321804}, {-0.411,     0.0322158}, {-0.4, 0.0320886}, {-0.233, 0.0320596}, {0.567,     0.00286087}, {0.578, -0.00143633}, {0.589, -0.00592979}, {0.6, \-0.0113609}};
In[2]:= DeleteCases[data, x_ /; x[[1]] > 0]
Out[2]= {{-0.5, 0.0321787}, {-0.489, 0.0321691}, {-0.478,   0.032211}, {-0.467, 0.0321723}, {-0.456, 0.0322448}, {-0.444,   0.0321498}, {-0.433, 0.032132}, {-0.422, 0.0321804}, {-0.411,   0.0322158}, {-0.4, 0.0320886}, {-0.233, 0.0320596}}
-Tomas

> Date: Wed, 26 Oct 2011 17:37:09 -0400
> From: mheaney at gmail.com
> Subject: simple question about removing elements from a table
> To: mathgroup at smc.vnet.net
>
> Hi,
>
> I have a data table:
>
> data={{-0.5, 0.0321787}, {-0.489, 0.0321691}, {-0.478,
> 0.032211}, {-0.467, 0.0321723}, {-0.456, 0.0322448}, {-0.444, 0.0321498},
> {-0.433, 0.032132}, {-0.422, 0.0321804}, {-0.411, 0.0322158},
> {-0.4, 0.0320886},  {-0.233,  0.0320596},  {0.567, 0.00286087}, {0.578,
> -0.00143633}, {0.589, -0.00592979}, {0.6, -0.0113609}}
> I want to remove all of the elements that have a positive first number, to
> get:
>
> datasubset={{-0.5, 0.0321787}, {-0.489, 0.0321691}, {-0.478,
> 0.032211}, {-0.467, 0.0321723}, {-0.456, 0.0322448}, {-0.444, 0.0321498},
> {-0.433, 0.032132}, {-0.422, 0.0321804}, {-0.411, 0.0322158},
> {-0.4, 0.0320886},  {-0.233,  0.0320596}}
>
>  How do I do this?
>
> Thanks,
>
> Michael
> --
> ------------------------------------------------------------
> Michael B. Heaney
> 3182 Stelling Drive
> Palo Alto, CA 94303 USA
> mheaney at alum.mit.edu