Sorting by 2 substrings in a string in Java

Question

Closed. This question needs to be more focused. It is not currently accepting answers. question from:https://stackoverflow.com/questions/65831157/sorting-by-2-substrings-in-a-string-in-java

Answer 1

You need to

1. split the strings

String[] split=string.split(" ");

2. test if the second substrings are the same

split1[1].equals(split2[1])

3. if they are the same, compare the days

Integer.parseInt(split1[0])<Integer.parseInt(split2[0]);

If not, compare the month names using an array with the month names or similar.

private static final String[] MONTHS={"Jan","Feb",...};
private int getMonthNumeric(String abbr){
    for(int i=0;i<MONTHS.length();i++){
        if(abbr.equals(MONTHS[i]){
            return i;
        }
    }
    return -1;
}
//in your comparator
getMonthNumeric(split1[1])<getMonthNumeric(split1[1])

A simple comparator (ignoring edge cases) could look like this (using a lambda):

(a,b)->{
    String[] split1=a.split(" ");
    String[] split2=b.split(" ");
    if(split1[1].equals(split2[1])){
        return Integer.parseInt(split1[0])-Integer.parseInt(split2[0]);
    }else{
        return getMonthNumeric(split1[1])-getMonthNumeric(split1[1]);
    }
}

Your code sorting the list could look like the following:

private static final String[] MONTHS={"Jan","Feb",...};
private int getMonthNumeric(String abbr){
    for(int i=0;i<MONTHS.length();i++){
        if(abbr.equals(MONTHS[i]){
            return i;
        }
    }
    return -1;
}
//Where you want to sort the date:
Collections.sort(dates,(a,b)->{
        String[] split1=a.split(" ");
        String[] split2=b.split(" ");
        if(split1[1].equals(split2[1])){
            return Integer.parseInt(split1[0])-Integer.parseInt(split2[0]);
        }else{
            return getMonthNumeric(split1[1])-getMonthNumeric(split1[1]);
        }
    }
);