* Inconsistency with sort -n?
@ 2008-12-31 21:39 Buchbinder, Barry (NIH/NIAID) [E]
2009-01-02 23:07 ` Dave Korn
2009-01-07 14:27 ` Eric Blake
0 siblings, 2 replies; 3+ messages in thread
From: Buchbinder, Barry (NIH/NIAID) [E] @ 2008-12-31 21:39 UTC (permalink / raw)
To: cygwin
`sort -n' and `sort -g' work inconsistently with 0 and -0 if there are leading spaces. Sometimes -0 is before 0, as I would expect, and sometimes it is afterwards. Adding `-b' does not seem to help.
Is this where I should report it or should I go upstream?
In case you are wondering why I want to do this: I'm counting items in a bin so the bin from -1 to 0 and 0 to +1 are different.
Please excuse the excessive number of examples.
Happy Gregorian New Year!
- Barry
Disclaimer: Statements made herein are not made on behalf of NIAID.
________________
$ echo 0 -1 -0 1 | tr ' ' '\n' | sort -n
-1
-0
0
1
$ echo 0 -1 -0 1 | tr ' ' '\n' | sed -e 's/^/ /' | sort -n
-1
-0
0
1
$ echo 0 -1 -0 1 | tr ' ' '\n' | sed -e '/-/s/^/ /' | sort -n
-1
-0
0
1
$ echo 0 -1 -0 1 | tr ' ' '\n' | sed -e '/^.$/s/^/ /' | sort -n
-1
0
-0
1
$ echo 0 -1 -0 1 | tr ' ' '\n' | sed -e '/-/s/^/ /' -e 's/^/ /' | sort -n
-1
-0
0
1
$ echo 0 -1 -0 1 | tr ' ' '\n' | sed -e '/^.$/s/^/ /' -e 's/^/ /' | sort -n
-1
0
-0
1
$ echo 0 -1 -0 1 | tr ' ' '\n' | sed -e '/-/s/^/ /' -e 's/^/ /' | sort -n
-1
-0
0
1
$ echo 0 -1 -0 1 | tr ' ' '\n' | sed -e '/-/!s/^/ /' -e 's/^/ /' | sort -n
-1
0
-0
1
$ echo 0 -1 -0 1 | tr ' ' '\n' | sort -g
-1
-0
0
1
$ echo 0 -1 -0 1 | tr ' ' '\n' | sed -e 's/^/ /' | sort -g
-1
-0
0
1
$ echo 0 -1 -0 1 | tr ' ' '\n' | sed -e '/-/s/^/ /' | sort -g
-1
-0
0
1
$ echo 0 -1 -0 1 | tr ' ' '\n' | sed -e '/^.$/s/^/ /' | sort -g
-1
0
-0
1
$ echo 0 -1 -0 1 | tr ' ' '\n' | sed -e '/-/s/^/ /' -e 's/^/ /' | sort -g
-1
-0
0
1
$ echo 0 -1 -0 1 | tr ' ' '\n' | sed -e '/^.$/s/^/ /' -e 's/^/ /' | sort -g
-1
0
-0
1
$ echo 0 -1 -0 1 | tr ' ' '\n' | sed -e '/-/s/^/ /' -e 's/^/ /' | sort -g
-1
-0
0
1
$ echo 0 -1 -0 1 | tr ' ' '\n' | sed -e '/-/!s/^/ /' -e 's/^/ /' | sort -g
-1
0
-0
1
$ echo 0 -1 -0 1 | tr ' ' '\n' | sort -nb
-1
-0
0
1
$ echo 0 -1 -0 1 | tr ' ' '\n' | sed -e 's/^/ /' | sort -nb
-1
-0
0
1
$ echo 0 -1 -0 1 | tr ' ' '\n' | sed -e '/-/s/^/ /' | sort -nb
-1
-0
0
1
$ echo 0 -1 -0 1 | tr ' ' '\n' | sed -e '/^.$/s/^/ /' | sort -nb
-1
0
-0
1
$ echo 0 -1 -0 1 | tr ' ' '\n' | sed -e '/-/s/^/ /' -e 's/^/ /' | sort -nb
-1
-0
0
1
$ echo 0 -1 -0 1 | tr ' ' '\n' | sed -e '/^.$/s/^/ /' -e 's/^/ /' | sort -nb
-1
0
-0
1
$ echo 0 -1 -0 1 | tr ' ' '\n' | sed -e '/-/s/^/ /' -e 's/^/ /' | sort -nb
-1
-0
0
1
$ echo 0 -1 -0 1 | tr ' ' '\n' | sed -e '/-/!s/^/ /' -e 's/^/ /' | sort -nb
-1
0
-0
1
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^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: Inconsistency with sort -n?
2008-12-31 21:39 Inconsistency with sort -n? Buchbinder, Barry (NIH/NIAID) [E]
@ 2009-01-02 23:07 ` Dave Korn
2009-01-07 14:27 ` Eric Blake
1 sibling, 0 replies; 3+ messages in thread
From: Dave Korn @ 2009-01-02 23:07 UTC (permalink / raw)
To: cygwin
Buchbinder, Barry (NIH/NIAID) [E] wrote:
> `sort -n' and `sort -g' work inconsistently with 0 and -0 if there are
> leading spaces. Sometimes -0 is before 0, as I would expect, and sometimes
> it is afterwards. Adding `-b' does not seem to help.
>
> Is this where I should report it or should I go upstream?
Kinda depends where it's coming from. Could be newlib, could be cygwin,
could be sort itself. Either the + and - zeros aren't being correctly
converted to their float representations, or the comparison of + vs. - zero
isn't working right, at a first guess.
> In case you are wondering why I want to do this: I'm counting items in a
> bin so the bin from -1 to 0 and 0 to +1 are different.
Hacky work-around: " | sort -r | sort [-n|-g] -s". First alphabetic sort
using -r gets all the negative numbers at the start of the list, then adding
stable flag to the numeric sort preserves their relative ordering when they
compare equal.
> Happy Gregorian New Year!
Happy Pastafarian Noodly YARRRR!
cheers,
DaveK
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^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: Inconsistency with sort -n?
2008-12-31 21:39 Inconsistency with sort -n? Buchbinder, Barry (NIH/NIAID) [E]
2009-01-02 23:07 ` Dave Korn
@ 2009-01-07 14:27 ` Eric Blake
1 sibling, 0 replies; 3+ messages in thread
From: Eric Blake @ 2009-01-07 14:27 UTC (permalink / raw)
To: cygwin
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According to Buchbinder, Barry (NIH/NIAID) [E] on 12/31/2008 2:29 PM:
[sorry for my delay in replying]
> `sort -n' and `sort -g' work inconsistently with 0 and -0 if there are leading spaces. Sometimes -0 is before 0, as I would expect, and sometimes it is afterwards. Adding `-b' does not seem to help.
>
> Is this where I should report it or should I go upstream?
If it were a bug, it would be an upstream issue (I reproduced your test
cases on Linux). But it is not a bug; sort is behaving as documented.
> $ echo 0 -1 -0 1 | tr ' ' '\n' | sed -e '/^.$/s/^/ /' | sort -n
> -1
> 0
> -0
> 1
sort -n sorts the entire line based on numeric value (0 and -0 have the
same value), then breaks ties based on byte-wise values (' ' comes before
'-').
> $ echo 0 -1 -0 1 | tr ' ' '\n' | sed -e '/^.$/s/^/ /' | sort -g
> -1
> 0
> -0
> 1
sort -g is slower than sort -n, because it converts to floating point; and
although -0.0 and +0.0 are distinct bit patterns, they still sort equal,
so you ware once again back to the fallback of bytewise comparison to
break ties (and ' ' still comes before '-').
Use sort -u to see that 0 and -0 sort numerically equal, and thus why a
fallback sort must be attempted.
$ echo 0 -1 -0 1 | tr ' ' '\n' | sed -e '/^.$/s/^/ /' | sort -nu
-1
0
1
Or, go one better - use two sort keys. Make the primary key sort
numerically, and the second sort key break ties in favor of '-':
$ echo 0 -1 -0 1 | tr ' ' '\n' | sed -e '/^.$/s/^/ /' | sort -k1,1n -k1r
-1
-0
0
1
--
Don't work too hard, make some time for fun as well!
Eric Blake ebb9@byu.net
volunteer cygwin coreutils maintainer
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2008-12-31 21:39 Inconsistency with sort -n? Buchbinder, Barry (NIH/NIAID) [E]
2009-01-02 23:07 ` Dave Korn
2009-01-07 14:27 ` Eric Blake
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