Re: select 1st column element based on criteria in 2nd column in mathematica

*To*: mathgroup at smc.vnet.net*Subject*: [mg124196] Re: select 1st column element based on criteria in 2nd column in mathematica*From*: "Oleksandr Rasputinov" <oleksandr_rasputinov at hmamail.com>*Date*: Thu, 12 Jan 2012 04:21:45 -0500 (EST)*Delivered-to*: l-mathgroup@mail-archive0.wolfram.com

Or maybe: Pick[#1, Thread[#2 > 3]] & @@ Transpose[pairs] On Wed, 11 Jan 2012 22:25:16 -0000, Murray Eisenberg <murray at math.umass.edu> wrote: > You cannot directly select from a "table", as there is no such object in > Mathematica. You want to select from a list of 2-element lists. (You may > _display_ such a list of lists in Table form, but such a display is not > an object upon which you'd want to operate.) > > So do it like this (among other ways): > > pairs = {{1,3}, {2,4}, {3,6}, {4,1}, {5,3}, {6,2}, {7,5}, {8,2}}; > First /@ Select[pairs, Last[#] > 3 &] > > The Select function pulls out those pairs that satisfy your condition; > the condition is specified by the "pure function" that's the 2nd > argument to Select. Finally, mapping First (First /@ ...) onto the > result gives the first member of each pair selected. > > On 1/11/12 4:18 AM, Hani wrote: >> hello, I have a question. >> >> Suppose I have a table with two columns like this: >> >> 1 3 >> 2 4 >> 3 6 >> 4 1 >> 5 3 >> 6 2 >> 7 5 >> 8 2 >> >> I want to select elements of the 1st column which its corresponding 2nd >> column elements are bigger than 3. so, the result should be {2,3,7}. >> How to >> implement that in mathematica? Thanx a lot