Re: Help! Delete Casses based on column

*To*: mathgroup at smc.vnet.net*Subject*: [mg58306] Re: Help! Delete Casses based on column*From*: Bill Rowe <readnewsciv at earthlink.net>*Date*: Sun, 26 Jun 2005 23:13:09 -0400 (EDT)*Sender*: owner-wri-mathgroup at wolfram.com

On 6/26/05 at 1:33 AM, tornado78 at hotmail.com (tornado78) wrote: >I need to take a large numeric matrix and remove all the rows that >have a value less than X in column N First, using Table to generate a random matrix In[1]:= data = Table[Random[], {i, 5}, {j, 5}] Out[1]= {{0.7782881593866494, 0.6753591418097964, 0.9449449797796714, 0.37735570973406635, 0.6250430512630213}, {0.7774244995727889, 0.6447847938619459, 0.8176979735737523, 0.8623853364999774, 0.0803196694199144}, {0.8740035700727821, 0.402979840643203, 0.46652340639843337, 0.8909105854301345, 0.3997272322978968}, {0.6150459139286458, 0.5304020309232242, 0.12667830628081253, 0.6939192674223005, 0.8949467718141887}, {0.44714646243832995, 0.17821492267582964, 0.5725611138098228, 0.3112823655223339, 0.6688583030516806}} Then Pick can be used to do what you want. That is dropping all of the rows which have a value of less than .5 in column 4 could be done as: In[2]:= Pick[data, (#1 >= 0.5 & ) /@ data[[All,4]]] Out[2]= {{0.7774244995727889, 0.6447847938619459, 0.8176979735737523, 0.8623853364999774, 0.0803196694199144}, {0.8740035700727821, 0.402979840643203, 0.46652340639843337, 0.8909105854301345, 0.3997272322978968}, {0.6150459139286458, 0.5304020309232242, 0.12667830628081253, 0.6939192674223005, 0.8949467718141887}} -- To reply via email subtract one hundred and four