Services & ResourcesWolfram ForumsMathGroup Archive

[Date Index] [Thread Index] [Author Index]

sorting problem

• To: mathgroup at smc.vnet.net
• Subject: [mg130633] sorting problem
• From: S <dsalman96 at gmail.com>
• Date: Sun, 28 Apr 2013 00:57:59 -0400 (EDT)
• Delivered-to: l-mathgroup@mail-archive0.wolfram.com
• Delivered-to: l-mathgroup@wolfram.com
• Delivered-to: mathgroup-outx@smc.vnet.net
• Delivered-to: mathgroup-newsendx@smc.vnet.net

Hello 

I need to sort a list in increasing magnitude. If two elements in the list are the same, the element which appears EARLIER in the list should appear first. Finally, I need the indices of the sorted list according to the above two rules.

e.g. for input 
distances = {0, Sqrt[2], Sqrt[2], 0, 0, Sqrt[2], 2, Sqrt[2]}
I need the answer to be 
k={1,4,5,2,3,6,8,7}

I tried the following commands:

distances = {0, Sqrt[2], Sqrt[2], 0, 0, Sqrt[2], 2, Sqrt[2]}
Sorteddistances = Sort[distances, Less]
k = Ordering[distances]

I get output k={1, 4, 5, 7, 2, 3, 6, 8}.

However, I want the output k={1,4,5,2,3,6,8,7}

Can someone please suggest how to do this.

Thanks

S

• Follow-Ups:
  • Re: sorting problem
    • From: Fred Simons <f.h.simons@tue.nl>