Re: SortBy won't order irrationals
- To: mathgroup at smc.vnet.net
- Subject: [mg124046] Re: SortBy won't order irrationals
- From: Shizu <slivo.vitz at msa.hinet.net>
- Date: Sat, 7 Jan 2012 05:18:26 -0500 (EST)
- Delivered-to: l-mathgroup@mail-archive0.wolfram.com
It's normal, since Mathematica sorts by structure.
This could be a simple solution:
In[]:= Sort[ptsIrr, #1[[2]] < #2[[2]] &]
Out[]:= {{-1, 0}, {7, 0}, {Sqrt[3], 1}, {6, 1}, {Sqrt[5], 1}, {4, 1}, {1, Sqrt[2]}, {2, 2}, {0, 2}}
This sorts by structure:
In[]:= Sort[{Pi, E, 2, 3, 1, Sqrt[2]}]
Out[]:= {1, 2, 3, Sqrt[2], E, \[Pi]}
This sorts by numerical values:
In[]:= Sort[{Pi, E, 2, 3, 1, Sqrt[2]}, Less]
Out[]:= {1, Sqrt[2], 2, E, 3, \[Pi]}
With SortBy[], simply you have to N[] as you did.