String compare oddity [modified]

[PIEBALDconsult]

I was looking at sorting some strings today and noticed that the default comparer orders them wrong -- it sorts "a" before "A", rather than after it, for instance. So I looked into it and read up a bit and tried the InvariantCulture and the Ordinal comparer -- Ordinal works correctly, and I'll likely use it, but I'm not happy about it. According to http://msdn.microsoft.com/en-us/library/dd465121.aspx[^]: "Comparisons that use StringComparison.InvariantCulture and StringComparison.Ordinal work identically on ASCII strings." Which is not strictly true -- they order these differently. Does anyone here know how to make a Culture (based on en-US) that does a case-sensitive sort the right way? Edit: This is interesting... I was experimenting with the System.StringComparer.CurrentCultureIgnoreCase and discovered that it seems to do what I want -- at least in the tests I've made. Which is good. :thumbsup: But that means that it doesn't actually ignore the case! :sigh: Scratch that -- it's just an artifact of how I was testing it.

modified on Friday, August 19, 2011 2:13 PM

[Navin Pandit]

One way is to put each characters into an array and the sort the array. Second option is: convert each chars of string to ASCII value. Sort the value and then reconvert it to chars. Finally, merge the chars. You will get the sorted string.

[PIEBALDconsult]

That's equivalent to what the Ordinal comparer does. And I'm not sorting a string, I'm sorting a collection of strings.

[Lost User]

Ordinal does an ASCII compare.

PIEBALDconsult wrote:

I'll likely use it, but I'm not happy about it

Not happy about what?

"Don't confuse experts with facts" - Eric_V

[PIEBALDconsult]

About having to use the Ordinal comparer to get the correct (desired) case-sensitive sort order. I should be able to use a "linguistic" (I think that's the term the documentation used) Culture that produces the same sort order of ASCII data. And if I can create a Culture that does that and set it as my CurrentCulture, so much the better.

[Lost User]

PIEBALDconsult wrote:

I should be able to use a "linguistic" (I think that's the term the documentation used) Culture that produces the same sort order of ASCII data.

Different languages treat upper and lower case differently. While English considers a lowercase 'a' to be semantically "less than" the uppercase 'A', it may not be the same with other languages. I think that's why the designers of .NET chose to give us the language-neutral Ordinal option.

"Don't confuse experts with facts" - Eric_V

[PIEBALDconsult]

Shameel wrote:

English considers a lowercase 'a' to be semantically "less than" the uppercase 'A',

Got a reference for that? I think the opposite is true.

[Lost User]

PIEBALDconsult wrote:

Got a reference for that?

I don't have a reference, but working with customers, they like to see 'A' on top of lists and 'a' below that.

PIEBALDconsult wrote:

I think the opposite is true.

The opposite is true in case of ASCII.

"Don't confuse experts with facts" - Eric_V

[PIEBALDconsult]

Shameel wrote:

they like to see 'A' on top of lists and 'a' below that.

Exactly. That's how I want it, and the Ordinal comparer does it, but the InvariantCulture (and en-US) does it the other way. Edit: Well not exactly, come to think of it, because the Ordinal comparer also say "Z" < "a", which I don't want.

modified on Friday, August 19, 2011 12:15 PM

[Lost User]

PIEBALDconsult wrote:

Exactly. That's how I want it, and the Ordinal comparer does it

The Ordinal comparer uses the ASCII order of the characters.

Char Dec Oct Hex | Char Dec Oct Hex | Char Dec Oct Hex | Char Dec Oct Hex

(nul) 0 0000 0x00 | (sp) 32 0040 0x20 | @ 64 0100 0x40 | ` 96 0140 0x60
(soh) 1 0001 0x01 | ! 33 0041 0x21 | A 65 0101 0x41 | a 97 0141 0x61
(stx) 2 0002 0x02 | " 34 0042 0x22 | B 66 0102 0x42 | b 98 0142 0x62
(etx) 3 0003 0x03 | # 35 0043 0x23 | C 67 0103 0x43 | c 99 0143 0x63
(eot) 4 0004 0x04 | $ 36 0044 0x24 | D 68 0104 0x44 | d 100 0144 0x64
(enq) 5 0005 0x05 | % 37 0045 0x25 | E 69 0105 0x45 | e 101 0145 0x65
(ack) 6 0006 0x06 | & 38 0046 0x26 | F 70 0106 0x46 | f 102 0146 0x66
(bel) 7 0007 0x07 | ' 39 0047 0x27 | G 71 0107 0x47 | g 103 0147 0x67
(bs) 8 0010 0x08 | ( 40 0050 0x28 | H 72 0110 0x48 | h 104 0150 0x68
(ht) 9 0011 0x09 | ) 41 0051 0x29 | I 73 0111 0x49 | i 105 0151 0x69
(nl) 10 0012 0x0a | * 42 0052 0x2a | J 74 0112 0x4a | j 106 0152 0x6a
(vt) 11 0013 0x0b | + 43 0053 0x2b | K 75 0113 0x4b | k 107 0153 0x6b
(np) 12 0014 0x0c | , 44 0054 0x2c | L 76 0114 0x4c | l 108 0154 0x6c
(cr) 13 0015 0x0d | - 45 0055 0x2d | M 77 0115 0x4d | m 109 0155 0x6d
(so) 14 0016 0x0e | . 46 0056 0x2e | N 78 0116 0x4e | n 110 0156 0x6e
(si) 15 0017 0x0f | / 47 0057 0x2f | O 79 0117 0x4f | o 111 0157 0x6f
(dle) 16 0020 0x10 | 0 48 0060 0x30 | P 80 0120 0x50 | p 112 0160 0x70
(dc1) 17 0021 0x11 | 1 49 0061 0x31 | Q 81 0121 0x51 | q 113 0161 0x71
(dc2) 18 0022 0x12 | 2 50 0062 0x32 | R 82 0122 0x52 | r 114 0162 0x72
(dc3) 19 0023 0x13 | 3 51 0063 0x33 | S 83 0123 0x53 | s 115 0163 0x73
(dc4) 20 0024 0x14 | 4 52 0064 0x34 | T 84 0124 0x54 | t 116 0164 0x74
(nak) 21 0025 0x15 | 5 53 0065 0x35 | U 85 0125 0x55 | u 117 0165 0x75
(syn) 22 0026 0x16 | 6 54 0066 0x36 | V 86 0126 0x56 | v 118 0166 0x76
(etb) 23 0027 0x17 | 7 55 0067 0x37 | W 87 0127 0x57 | w 119 0167 0x77
(can) 24 0030 0x18 | 8 56 0070 0x38 | X 88 0130 0x58 | x

[PIEBALDconsult]

Yes, I know that, but I don't know who gave you the 1, take a 5 for your efforts.

[PIEBALDconsult]

What I came up with as a simple interim solution is this:

private sealed class MyComparer : System.Collections.Generic.IComparer
{
public int
Compare
(
string Op0
,
string Op1
)
{
int result = System.StringComparer.InvariantCultureIgnoreCase.Compare ( Op0 , Op1 ) ;

    if ( result == 0 )
    {
        result = System.StringComparer.InvariantCulture.Compare ( Op0 , Op1 ) \* -1 ;
    }

    return ( result ) ;
}

}

[Lost User]

PIEBALDconsult wrote:

I don't know who gave you the 1

I get downvoted all the time and the people who do it do not have the courage to own up and explain it.

PIEBALDconsult wrote:

take a 5 for your efforts

Thanks :-)

"Don't confuse experts with facts" - Eric_V