Function that compares 2 alpha-numeric values?

Discussion in 'Javascript' started by success_ny, Jul 21, 2005.

  1. success_ny

    success_ny Guest

    Does anyone have a code snippet to compare those values so I can sort
    the array of alpha-numeric values that include both characters and
    integers in it?

    I.e., if we have values like 4236 and 123234, I want 4236 to be second
    because 4 is bigger than 1 rather than using the numeric comparison.
    The strings can include character values and strings. Basically, I have
    the bubble sort function, the question is how to compare those types of
    strings in the alpha-numeric order.

    i.e.,

    A83745
    B34974
    127734
    34456
    788

    I looked all over the web thinking that this simple question would be
    answered somewhere, but could not find the answer. Please help.

    Thanks!
     
    success_ny, Jul 21, 2005
    #1
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  2. success_ny

    VK Guest


    The time I wrote this script (a while ago) I was crying for Perl with
    his "cmp" and shuttle <=> Get's really "if'y" in JavaScript w/o them
    :)


    function alfanum(a,b) {
    var result = 0;
    if ((typeof(a)=='number')&&(typeof(b)=='number')) {
    result = a-b;
    }
    else if ((typeof(a)=='string')&&(typeof(b)=='string')) {
    if (a < b) {result = -1;}
    else if (a > b) {result = 1;}
    else {result = 0;}
    }
    else if (typeof(a)=='string'){
    result = 1;
    }
    else {
    result = -1
    }
    return result;
    }

    var arr = [9,'A',8,'B',7,'C',6,'D',5,'E',4,'F',3,'G',2,'H',1];

    alert(arr.sort(alfanum));
     
    VK, Jul 21, 2005
    #2
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  3. JRS: In article <>
    , dated Thu, 21 Jul 2005 08:42:47, seen in posted :
    As you've looked all over the Web I assume that there is no need to
    repeat what you found on my Web site.

    The default array sort would be to treat letters as bigger than digits;
    no added code would be needed. That would give 12 34 78 A8 B3. You
    don't need to write and download a sort algorithm. Use that order if
    you can.

    How can a string include a string?

    You need to do one of two things : write a comparison function for
    array.sort to use, or transform your data so that it will sort in the
    right order, de-transforming afterwards. Since array.sort on a list of
    N items will call the sort function >0(N) times, you should transform
    the data if N is large.

    The simplest transform might be to take each character of a string in
    turn (I assume less than 240 possibilities), look up its rank in a
    priority list, encode that as two Hex characters after adding 16, pad
    with a "character" 00, and append the original data so that de-
    transformation is just a substring operation.
     
    Dr John Stockton, Jul 21, 2005
    #3
  4. success_ny

    askMe Guest

    Try a loop over the whole set first to separate the numeric from the
    alphas with isNan. Run a sort on the numbers array, then a sort on the
    alpha array. Add the sort alpha array elements to the end of the
    numeric array.

    http://www.askblax.com
     
    askMe, Jul 22, 2005
    #4
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