Java regex parse sections of long text

Question

I have a huge txt that can contain several house names and, for each house, there are some values specific to that specific house, and so on. Here is a similar part of my txt:

getHouseName: house1
random useless text
price: 1000
squaremtr: 75
sellVal: 1000
random useless text
random useless text
random useless text
rentPrice: 150
getHouseName: house2
price: 1004
squaremtr: 85
sellVal: 950
random useless text
rentPrice: 150
getHouseName: house3
price: 1099
squaremtr: 90
random useless text
random useless text
sellVal: 1100
random useless text
rentPrice: 199

I would like, for every house, to retrieve values specific for each house and store them into a variable using regexes. Right now this is my code:

public void testHouse() {
    Scanner txt = new Scanner(new File("path//to//file"));

    String houseName ="";
    String price = "";
    String squaremtr = "";
    String sellVal = "";
    String rentPrice = "";
    
    Pattern houseNamePatt = Pattern.compile("getHouseName: ((_!getHouseName: \\s).)*", Pattern.DOTALL);

    while(txt.hasNextLine()) {
        String str = txt.nextLine();
        Matcher m = houseNamePatt.matcher(str);
        if(m.find) {
            houseName=str.substring(m.end());
            System.out.println("houses: " + m.group());
        }
    }
}

But in this case I'm just getting a list with all the house names, not the lines between each name and I definitely can't assign the values of a specific house to my variables. Where am I wrong? Thank you

If you want the variables with the values, you can use capturing groups and use a pattern to get the values line by line. getHouseName:\h+(.*)\Rprice:\h+(\d+) etc.. — The fourth bird
– The fourth bird, Commented Nov 20, 2020 at 12:52

The fourth bird · Accepted Answer · 2020-11-20 16:34:54Z

2

You can get all values by matching the names followed by a capturing group. If there are lines in between with random values, you can match all lines that do not start with the next expected value using a negative lookahead (?!

Then set the values of the variables equals to the group number.

^getHouseName:\h+(.+)(?:\R(?!price:).*)*\Rprice: (\d+)(?:\R(?!squaremtr:).*)*\Rsquaremtr:\h+(\d+)(?:\R(?!sellVal:).*)*\RsellVal:\h+(\d+)(?:\R(?!rentPrice:).*)*\RrentPrice:\h+(\d+)

In parts:

^ Start of string
getHouseName:\h+(.+) Match the value for getHouseName in group 1
(?:\R(?!price:).*)*\Rprice: (\d+) Match until the next line with price, capture 1+ digits in group 2
(?:\R(?!squaremtr:).*)*\Rsquaremtr:\h+(\d+) Match until the next line with squaremtr, capture 1+ digits in group 3
(?:\R(?!sellVal:).*)*\RsellVal:\h+(\d+) Match until the next line with sellVal, capture 1+ digits in group 4
(?:\R(?!rentPrice:).*)*\RrentPrice:\h+(\d+) Match until the next line with rentPrice, capture 1+ digits in group 5

Regex demo

answered Nov 20, 2020 at 16:34

The fourth bird

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1 Comment

thranduil90 Over a year ago

Thanks! I'll try

Andreas · Accepted Answer · 2020-11-20 13:01:24Z

1

The following regex will do it:

(?m)^getHouseName: (.*)\\Rprice: (.*)\\Rsquaremtr: (.*)\\RsellVal: (.*)\\RrentPrice: (.*)

Test

String hugeText = "getHouseName: house1\n" + 
                  "price: 1000\n" + 
                  "squaremtr: 75\n" + 
                  "sellVal: 1000\n" + 
                  "rentPrice: 150\n" + 
                  "getHouseName: house2\n" + 
                  "price: 1004\n" + 
                  "squaremtr: 85\n" + 
                  "sellVal: 950\n" + 
                  "rentPrice: 150\n" + 
                  "getHouseName: house3\n" + 
                  "price: 1099\n" + 
                  "squaremtr: 90\n" + 
                  "sellVal: 1100\n" + 
                  "rentPrice: 199";

String regex = "(?m)^" +
               "getHouseName: (.*)\\R" + 
               "price: (.*)\\R" + 
               "squaremtr: (.*)\\R" + 
               "sellVal: (.*)\\R" + 
               "rentPrice: (.*)";
for (Matcher m = Pattern.compile(regex).matcher(hugeText); m.find(); ) {
    String houseName = m.group(1);
    String price     = m.group(2);
    String squaremtr = m.group(3);
    String sellVal   = m.group(4);
    String rentPrice = m.group(5);
    System.out.printf("%-8s %6s %4s %6s %5s%n",
                      houseName, price, squaremtr, sellVal, rentPrice);
}

Output

house1     1000   75   1000   150
house2     1004   85    950   150
house3     1099   90   1100   199

answered Nov 20, 2020 at 13:01

Andreas

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2 Comments

thranduil90 Over a year ago

I modified my question, because I have some random text between the values. How can I modify that according to the complex text?

Andreas Over a year ago

@thranduil90 Please be more accurate when asking. Are the 5 values you're always present, and are they always in the same order? Make sure question has the full specification of what you're looking for.

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