property NSArray : a reference to current application’s NSArray
property NSString : a reference to current application’s NSString
property NSLocale : a reference to current application’s NSLocale
property NSDictionary : a reference to current application’s NSDictionary
property NSCountedSet : a reference to current application’s NSCountedSet
property NSMutableArray : a reference to current application’s NSMutableArray
property NSSortDescriptor : a reference to current application’s NSSortDescriptor
property NSDateFormatter : a reference to current application’s NSDateFormatter

set aList to {"2006-06-27 02:38:52", "2008-03-09 19:08:05", "2008-03-09 19:29:29"}
set aRes to totalDateStrByYear(aList, "yyyy-MM-dd HH:mm:ss") of me
–> {{aCount:1, aKey:2006}, {aCount:2, aKey:2008}}

–日付テキストを年単位で集計
on totalDateStrByYear(aList, strFormat)
　　set theCountedSet to NSCountedSet’s |set|()
　　set newArray to NSMutableArray’s new()
　　
　　repeat with i in aList
　　　　set postDate to dateFromStringWithDateFormat(i, strFormat) of me –日付テキストをDate Objectに変換
　　　　set yearStr to (year of postDate) –「年」の数字
　　　　(newArray’s addObject:yearStr)
　　end repeat
　　
　　set resArray to countItemsByItsAppearance(newArray) of me
　　set bList to sortRecListByLabel(resArray, "aKey", true) of me –昇順ソート
　　return bList
end totalDateStrByYear

–日付文字列からdate objectを作成する
on dateFromStringWithDateFormat(dateString, dateFormat)
　　set dStr to NSString’s stringWithString:dateString
　　set dateFormatStr to NSString’s stringWithString:dateFormat
　　
　　set aDateFormatter to NSDateFormatter’s alloc()’s init()
　　aDateFormatter’s setDateFormat:dateFormatStr
　　aDateFormatter’s setLocale:(NSLocale’s alloc()’s initWithLocaleIdentifier:"en_US_POSIX")
　　
　　set aDestDate to (aDateFormatter’s dateFromString:dStr)
　　
　　return aDestDate as list of string or string
end dateFromStringWithDateFormat

–登場頻度でリストを集計する
on countItemsByItsAppearance(aList)
　　set aSet to NSCountedSet’s alloc()’s initWithArray:aList
　　set bArray to NSMutableArray’s array()
　　set theEnumerator to aSet’s objectEnumerator()
　　
　　repeat
　　　　set aValue to theEnumerator’s nextObject()
　　　　if aValue is missing value then exit repeat
　　　　bArray’s addObject:(NSDictionary’s dictionaryWithObjects:{aValue, (aSet’s countForObject:aValue)} forKeys:{"aKey", "aCount"})
　　end repeat
　　
　　return bArray
end countItemsByItsAppearance

–リストに入れたレコードを、指定の属性ラベルの値でソート
on sortRecListByLabel(aRecList as list, aLabelStr as string, ascendF as boolean)
　　set aArray to NSArray’s arrayWithArray:aRecList
　　
　　set sortDesc to NSSortDescriptor’s alloc()’s initWithKey:aLabelStr ascending:ascendF
　　set sortDescArray to NSArray’s arrayWithObjects:sortDesc
　　set sortedArray to aArray’s sortedArrayUsingDescriptors:sortDescArray
　　
　　set bList to (sortedArray) as list of string or string
　　return bList
end sortRecListByLabel