! operator
- To: mathgroup at smc.vnet.net
- Subject: [mg55927] ! operator
- From: "DongGook Park" <dgpark6 at sunchon.ac.kr>
- Date: Sun, 10 Apr 2005 06:55:02 -0400 (EDT)
- Sender: owner-wri-mathgroup at wolfram.com
Hi,
Could you explain a mysterious behaviour of "! operator" as shown below?
In[43]:=
MemberQ[{1,2,3},3]
Out[43]=
True
In[47]:=
!MemberQ[{1,2,3},3]
(* Here Mathematica does not give any response! *)
In[48]:=
Not@MemberQ[{1,2,3},3]
Out[48]=
False
Considering the description from Mathematica help:
"!expr is the logical NOT function. It gives False if expr is True,
and True if it is False."
This behaviour seems quite suspicious?
DongGook
----------------------------------
DongGook Park,
School of Information Technology,
SunChon University, Korea
Telephone: +82 61 750 3597
Mobile: +82 18 732 2125
Home page: http://www.dgpark6.com/
Email: dgpark6 at sunchon.ac.kr
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