functions - Filtering Lists in Mathematica

Possible Duplicate:
Select/Delete with Sublist elements?

I need help in filtering long lists of x,y coordinates.Lets use the following list as an example:

list={{3,5},{7,6},{15,6},{23,123}}

I need to filter out all the data points for which x<10. Therefore once the filtering is complete the new list should be:

newlist={{15,6},{23,123}}

Please help.Thank you!

Answer

 list = {{3, 5}, {7, 6}, {15, 6}, {23, 123}}

 DeleteCases[list, {x_, _} /; x < 10]
 DeleteCases[list, {_?(# < 10 &), _}]

 Cases[list, {x_, _} /; x >= 10]
 Cases[list, {_?(# >= 10 &), _}]
 Select[list, First[#] >= 10 &]
 Pick[list, First[#] >= 10 & /@ list]
 list /. {x_, _} /; x < 10 :> Sequence[]
 list /. {_?(# < 10 &), _} :> Sequence[]
 (* {{15, 6}, {23, 123}} *)

Comments

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