CODEWITHSUNDEEP
javastring
Chetan Hireholi
Chetan Hireholi

Reputation: 79

Iterate through a List of Strings starting from 'One' String until 'Another' String in Java

I'm trying to iterate through a List of Strings in Java. My List consists of:

["DataFileDownload/FD/722066/71493/2016/12/30/untitled-1.aux","DataFileDownload/FD/722066/71493/2016/12/31/untitled-2.aux","DataFileDownload/FD/722066/71493/2017/01/01/untitled-3.aux","DataFileDownload/FD/722066/71493/2016/01/02/untitled-4.aux"]

And I am reading the dates from the user as:

SimpleDateFormat fmt = new SimpleDateFormat("yyyy-MM-dd");
Date fromDate = fmt.parse("2016-12-30");
Date toDate = fmt.parse("2017-01-02");
Calendar fromCal = Calendar.getInstance();
fromCal.setTime(fromDate);
String fromYear = String.valueOf(fromCal.get(Calendar.YEAR));
String fromMonth = String.valueOf(fromCal.get(Calendar.MONTH)+1);
String fromDay = String.valueOf(fromCal.get(Calendar.DAY_OF_MONTH));
Calendar toCal = Calendar.getInstance();
toCal.setTime(toDate);
String toYear = String.valueOf(toCal.get(Calendar.YEAR));
String toMonth = String.valueOf(toCal.get(Calendar.MONTH)+1);
String toDay = String.valueOf(toCal.get(Calendar.DAY_OF_MONTH));

If I wanted to extract the Strings from date: 30-dec-2016 to 01-Jan-2017, i.e.

"DataFileDownload/FD/722066/71493/2016/12/30/untitled-1.aux","DataFileDownload/FD/722066/71493/2016/12/31/untitled-2.aux","DataFileDownload/FD/722066/71493/2017/01/01/untitled-3.aux"

I'm using the below loop:-

for(String s : NameList){
    if((s.equals(fromYear) && s.equals(fromMonth) && s.equals(fromDay)) == true){
  while((s.equals(toYear) && s.equals(toMonth) && s.equals(toDay)) != true){
     System.out.println(s);
  }
  System.out.println(s);
}

I get no result.

But when I try this:

       for(String s : objectNameList){
           if((s.contains(fromYear) && s.contains(fromMonth) && s.contains(fromDay))){
               System.out.println(s);
           }
       }

I get only:

"DataFileDownload/FD/722066/71493/2016/12/30/untitled-1.aux"

Can anyone please let me know how can I improve my loop condition?

Thanks in advance!

Upvotes: 0

Views: 89

Answers (2)

D.Karthikeyan
D.Karthikeyan

Reputation: 118

Convert the date values from String to Integer.

 int fromYear=Integer.parseInt(String.valueOf(fromCal.get(Calendar.YEAR)));
 int fromMonth=Integer.parseInt(String.valueOf(fromCal.get(Calendar.MONTH)+1));
 int fromDay = Integer.parseInt(String.valueOf(fromCal.get(Calendar.DAY_OF_MONTH)));

 int toYear = Integer.parseInt(String.valueOf(toCal.get(Calendar.YEAR)));
 int toMonth = Integer.parseInt(String.valueOf(toCal.get(Calendar.MONTH)+1));
 int toDay =   Integer.parseInt(String.valueOf(toCal.get(Calendar.DAY_OF_MONTH)));

Then split the Sting List and get year, month, day from the string inside the for block

 String[] f = s.split("/");      
 int year1 = Integer.parseInt(f[4]);
 int month1 = Integer.parseInt(f[5]);
 int day1 = Integer.parseInt(f[6]);

Then apply the logic to match date in between from date and to date

            if((fromYear <  year1) && (toYear >  year1))
                    {
                            System.out.println(s);  
                    }
                    else if((fromYear ==  year1))
                    {
                            if((fromMonth <=  month1) && (fromDay >= day1))
                            {
                                    System.out.println(s);
                            }
                    }
                    else if((toYear ==  year1))
                    {
                            if((toMonth >=  month1) || (toDay == day1))
                            {
                                    System.out.println(s);
                            }
                    }

Upvotes: 1

SHG
SHG

Reputation: 2616

Go string by string in your list and extract the date using regular expression, something like this:

private static String getDate(String str) {
    Pattern regex = Pattern.compile("\\.*(?<date>([0-9]{4}\\/[0-9]{2}\\/[0-9]{2}))");
    Matcher matcher = regex.matcher(str);
    boolean success = matcher.find();
    return (success ? matcher.group("date") : null);
}

// Example:
String dateStr = getDate("DataFileDownload/FD/722066/71493/2016/12/30/untitled-1.aux");

Save it as a Date object:

SimpleDateFormat fmt = new SimpleDateFormat("yyyy/MM/dd");
Date date = fmt.parse(dateStr);

Then, read the input dates from the user and save them as Date objects.

Then, you can compare the user dates and the dates from the list using:

java.util.Date.before(Date when);
java.util.Date.after(Date when);

Much easier than parsing all the dates and playing with strings.

Upvotes: 2

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