BinaryWrite and Position in Mathematica 6
- To: mathgroup at smc.vnet.net
- Subject: [mg83244] BinaryWrite and Position in Mathematica 6
- From: "L. Dwynn Lafleur" <lafleur at louisiana.edu>
- Date: Fri, 16 Nov 2007 05:22:09 -0500 (EST)
- Organization: U of Louisiana at Lafayette
I do not understand the following results from Mathematica 6.0.1.0 running
in Windows XP (SP2):
In[1]:= a={{2}}
Out[1]= {{2}}
In[2]:= b=Position[{x,y,z},y]
Out[2]= {{2}}
In[3]:= a==b
Out[3]= True
>From the above results, we see that although they produced differently, a
and b are apparently identical. Now I attempt to write each to a file using
BinaryWrite:
In[4]:= BinaryWrite["aFile.dat",a,"Integer32"]
Out[4]= aFile.dat
In[5]:= BinaryWrite["bFile.txt",b,"Integer32"]
During evaluation of In[5]:= BinaryWrite::nocoerce: {2} cannot be
coerced to the specified format. >>
Out[5]= $Failed
BinaryWrite writes a successfully, but fails on b. However, consider the
following:
In[6]:= BinaryWrite["bFile2.txt",ToExpression[b],"Integer32"]
Out[6]= bFile2.txt
Why do I need to convert b before writing it to a file? I thought that
"a==b -> True" indicates a and b are identical and therefore should be
treated in the same way by Mathematica. What am I overlooking?
====================================
L. Dwynn Lafleur
Professor of Physics
University of Louisiana at Lafayette
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