4
$\begingroup$

This question already has an answer here:

I have the following:

animals = {{dog, black, 200}, {cat, white, 100}, {moose, brown, 500}, {zebra,black,100}}

If this came from a SQL table called animals, which has fields named: type of animal, color, weight

I would say:

Select * from animals WHERE weight = 100

How do you do this in Mathematica?

$\endgroup$

marked as duplicate by Mr.Wizard Apr 30 '14 at 8:11

This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.

7
$\begingroup$
animals={{dog,black,200},{cat,white,100},{moose,brown,500},{zebra,black,100}}

Cases[animals,{_,_,100}]

(*or*)

Select[animals,#[[3]]==100&]

Among others...

$\endgroup$
  • $\begingroup$ Thanks!... I am new to Mathematica and I am finding getting up to speed despite reading 5 books on it is hard. Appreciate the help! $\endgroup$ – David Kerr Apr 6 '14 at 1:39
  • $\begingroup$ @DavidKerr: Have a look at q/a here and here. Both excellent mini-tutorials at this very site. $\endgroup$ – ciao Apr 6 '14 at 1:52
  • $\begingroup$ Thanks for the links. So for say greater than 100 how would you do that in the Cases command? I figured out how to do in select. What does the # and & do in cases? $\endgroup$ – David Kerr Apr 6 '14 at 2:02
  • $\begingroup$ Cases[animals,{_,_,x_/;x>100}]. The x gives the placeholder a name you can then do things with (like test). The # and & in Select are placeholder (slot) and pure-function elements. Check the docs for Select, it covers it there. $\endgroup$ – ciao Apr 6 '14 at 5:09
  • $\begingroup$ Thanks. If you get pointed in the right direction with a few hints it gives geometric progress! $\endgroup$ – David Kerr Apr 6 '14 at 13:33

Not the answer you're looking for? Browse other questions tagged or ask your own question.