- 319 B.C.: Something happened.
- 57: Something happened in the middle of those dates.
- 1976: Something else happened.
- 2001: The last important thing happened.
- 1976: Something else happened.
- 2001: The last important thing happened.
- 319 B.C.: Something happened.
- 57: Something happened in the middle of those dates.
If we could grab the first word, or first number, we could then sort it numerically by converting the first word to a number and sorting numerically. That is actually quite easy. But if we did that, then this list would be sorted in this order:
- 57: Something happened in the middle of those dates.
- 319 B.C.: Something happened.
- 1976: Something else happened.
- 2001: The last important thing happened.
To solve the problem, I created a user sort function to change the way the .sort() method works. The function is below...
var unsorted = String ( '1964: something\r350 B.C.: more text\r1756: text.\r319 bc: stuff\r1500 no colon').split('\r') ;
var sortedWrong = String ( '1964: something\r350 B.C.: more text\r1756: text.\r319 bc: stuff\r1500 no colon').split('\r').sort() ;
var sortedCorrectly = String ( '1964: something\r350 B.C.: more text\r1756: text.\r319 bc: stuff\r1500 no colon').split('\r').sort(sortStringsWithLeadingDate) ;
//
function sortStringsWithLeadingDate (arg1,arg2) {
//-------------------------------------------------------------------------
//-- S O R T S T R I N G S W I T H L E A D I N G D A T E
//-------------------------------------------------------------------------
//-- Generic: Yes. ECMA Script, JavaScript, ExtendScript
//-------------------------------------------------------------------------
//-- Purpose: This is a helper function to sort the elements of an aray
//-- such those created from an array of paragraphs from stories such
//-- as 'Today in History' -- a column frequently run in newspapers.
//-- That text has dates that are followed by a colon, but sometimes
//-- those dates have B.C. BC dates should sort before the non
//-- BC dates. This custom function helps do that.
//-------------------------------------------------------------------------
//-- Returns: The standard return for a user sort function. 0 if the
//-- first argument is the same as the second function. A negative
//-- number if the 2nd number is greater (or sorts after) the 1st
//-- number. A positive number if the opposite is true.
//-------------------------------------------------------------------------
//-- Calls: an internal function: determineDate which attempts to
//-- return a Number for the date. BC dates are returned as a
//-- negative number, positive dates as positive dates. And when no
//-- date can be determine, the original string will be passed back.
//-------------------------------------------------------------------------
//-- Standard use: Assume that you have an array of strings that looks
//-- similar to the following:
//-- var dts = [1964: something happened\r','350 B.C.: something happened a long time ago\r','1756: Something fundamental happened.\r']
//-- dts.sort(sortStringsWithLeadingDate)
//-- // now the dts array will be sorted by date.
//-------------------------------------------------------------------------
//-- Written by Jon S. Winters of electronic publishing support
//-- eps@electronicpublishingsupport.com
//-- Written: 2009.07.02 in Newark, New Jersey
//-------------------------------------------------------------------------
//-- Use the internal function to attempt to get a number for the
//-- lead date of each argument passed to the this user sort function
var arg1Date = determineDate ( arg1 ) ;
var arg2Date = determineDate ( arg2 ) ;
//-- If those two things did return dates, then the standard method
//-- of sorting has the only needs to return the difference between
//-- the second number and first number.
var subResults = arg1Date - arg2Date ;
if ( ! isNaN ( subResults ) ) {
//-- if that value of subtracting is Not a Number we can't use
//-- the results.
return subResults ;
}
//-- if here then the results wasn't a number, so try an alphabetical
//-- comparison.
if ( arg1Date == arg2Date ) {
return 0 ;
}
else if ( arg1Date <>
return -1 ;
}
return 1 ;
//-- end of main function
function determineDate ( arg ) {
//---------------------------------------------------------------------
//-- D E T E R M I N E D A T E
//---------------------------------------------------------------------
//-- Generic: in concept, but very specific to the text to examine.
//---------------------------------------------------------------------
try {
//-- Using Regular Expressions, find all the text upto the first :
//-- If that isn't found the result can generate an error.
var lead = arg.match( RegExp ( '^(.+?):' ))[1] ;
//-- From that lead text, find the date of it which is a continue
//-- string of numbers
var year = lead.match( RegExp ( '\\d+' ) )[0] ;
//-- Now determine if that lead text also has a 'b' and a 'c' in
//-- that order. If so, return a negative value, if not, return
//-- a numeric version.
if ( new RegExp ( 'b.{1,3}c', 'i' ).test( lead ) ) {
return -year ;
}
return Number ( year ) ;
}
//-- in case any of that caused an error, return the the original value
catch ( err ) {
return arg ;
}
}//-- end of internal function
}
//
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