Testing for a vector of all reals

Asked Jan 27 '15 at 17:16

Active Jan 27 '15 at 17:17

Viewed 37 times

I want to test if an expression is a vector of all reals. I defined

RealVector[expr_]:=VectorQ[expr,NumberQ[#]&&(Head[#]===Real)];

Trying this on

RealVector[{1,2,3}]; RealVector[{1.,2.,3.}];

should return False and True, resp., but I get False and False. I do not understand what is wrong. Can you help me to fix it?

edited Jan 27 '15 at 17:17

Szabolcs

asked Jan 27 '15 at 17:16

Carlos Felippa

You missed the & after the pure function. Use NumberQ[#]&&(Head[#]===Real) &. Note the & at the end. The # signs should show as green in the notebook when used correctly, not pink. – Szabolcs Jan 27 '15 at 17:19
That said, this is simpler: realVectorQ[{___Real}] = True; realVectorQ[__] = False – Szabolcs Jan 27 '15 at 17:21
1

I just noticed that you have already posted the same question yesterday, and received the same response. Why did you post again? If you need additional clarifications, please explain what exactly was not clear in the answers people already gave you. Then people can explain. Re-postig the exact same question won't yield better results. – Szabolcs Jan 27 '15 at 17:23
1

Integers are reals. – David G. Stork Jan 27 '15 at 17:37
If you want to distinguish Integers from the other Reals: realVector[expr_] := VectorQ[expr, # \[Element] Reals && # \[NotElement] Integers &] – David G. Stork Jan 27 '15 at 18:06

0 Answers0