如何拆分给定特定格式的字符串？

Question

I have dates in string format that sometimes are like this: 05-11-2009 16:59:20 and sometime are like this: 2013-12-05T22:00:00:00Z and some other time are like this: 2013-12-05T22:00:00:00.000Z .

I wrote a function that extract the month day and year from those dates, but I would like a function that can work for all of them passing in input the format. something like:

function DateParts(datetime, format) {
    var matches = datetime.splitByFormat(format);

    this.getYear = function () {
       return matches[3];
    };
    this.getMonth = function () {
        return (matches[2] - 1) +"" ;
    };
    this.getDay = function () {
        return matches[1];
    };
    this.getHours = function () {
        return matches[4];
    };
    this.getMinutes = function () {
    return matches[5];
    };
    this.getSeconds = function () {
        return matches[6];
    };
};

Where format will be soething like "yyyy-mm-dd hh:MM:ss" or "dd-mm-yyyyThh:MM:ss.dddZ" or whatever.

Is there a nice way of creating the splitByFormat function without having to substring my head off?

Answer 1

One regex to find them all:

(((?<month>\d{2})-(?<day>\d{2})-(?<year>\d{4})\s(?<hour>\d{2}):(?<minute>\d{2}):(?<second>\d{2}))|((?<year>\d{4})-(?<month>\d{2})-(?<day>\d{2})T(?<hour>\d{2}):(?<minute>\d{2}):(?<second>\d{2}):(?<millisecond>\d{2})Z)|(?<year>(\d{4})-(?<month>\d{2})-(?<day>\d{2})T(?<hour>\d{2}):(?<minute>\d{2}):(?<second>\d{2}):(?<millisecond>\d{2})\.(?<centisecond>\d{3})Z))

If you use this regex string, you are able to just capture the different groupings:

• year
• month
• day
• hour
• minute
• second
• millisecond
• centisecond

Answer 2

What about this? anything better anyone?

function DateParts(datetime, format) {

    this.getYear = function () {
        if (format) {
            ind = format.indexOf("yyyy");
            return datetime.substring(ind, ind + 4);
        }
         return "";

    };
    this.getMonth = function () {
        if (format) {
            ind = format.indexOf("mm");
            return datetime.substring(ind, ind + 2);
        }
        return "";            
    };
    this.getDay = function () {
        if (format) {
            ind = format.indexOf("gg");
            return datetime.substring(ind, ind + 2);
       }
       return "";
    };
};

Answer 3

This simple class FormatAnalyzer could be a beginning. It works.

FormatAnalyzer f = new FormatAnalyzer("yyyy-mm-dd hh:MM:ss");
f.getYear("2013-07-11 15:39:00");
f.getMonth("2013-07-11 15:39:00");

where

public class FormatAnalyzer {

    private String format;
    private int yearBegin;
    private int yearEnd;
    private int monthBegin;
    private int monthEnd;
    // ...

    public FormatAnalyzer(String format) {
        this.format = format;
        analyzeFormat();
    }

    public String getYear(String date) {
        return date.substring(yearBegin, yearEnd);
    }

    public String getMonth(String date) {
        return date.substring(monthBegin, monthEnd);
    }

    private void analyzeFormat() {
        yearBegin = yearEnd = format.indexOf("y");
        while (format.indexOf("y", ++yearEnd) != -1) {
        }
        monthBegin = monthEnd = format.indexOf("m");
        while (format.indexOf("m", ++monthEnd) != -1) {
        }
        // and so on for year, day, ...
    }
}