Re: equaltity of lists

*To*: mathgroup at smc.vnet.net*Subject*: [mg19109] Re: [mg19036] equaltity of lists*From*: "Andrzej Kozlowski" <andrzej at tuins.ac.jp>*Date*: Thu, 5 Aug 1999 01:35:24 -0400*Sender*: owner-wri-mathgroup at wolfram.com

Mathenatica distinguishes between == (Equal) and === (SameQ). You can see the difference between then from online help: In[1]:= ?== lhs == rhs returns True if lhs and rhs are identical. In[2]:= ?=== lhs === rhs yields True if the expression lhs is identical\ to rhs, and yields False otherwise. In the case {a,b}=={b,a} Mathematica does not know if the expressions are indenitical or not becaue it does not know the values of a and b. So it retuns the input uneveluated. In th esecond case it also does not know the values of a and b but as it has to return True or False it chooses the latter. -- Andrzej Kozlowski Toyama International University JAPAN http://sigma.tuins.ac.jp http://eri2.tuins.ac.jp > > Von: Drago Ganic <drago.ganic at in2.hr> > An: mathgroup at smc.vnet.net <mathgroup at smc.vnet.net> > Datum: Mittwoch, 4. August 1999 01:06 > Betreff: [mg19036] equaltity of lists > > >>Hi !! >> >>Why don't I get an answer (False) when I ask Mathematica >> >> {a,b}=={b,a} >> >>like the one I get with >> >> {1,2}=={2,1} >> False >> >>Greetings from Croatia, >>Drago Ganic >> >> >> >> > >