CODEWITHSUNDEEP
javaregextext-filesbufferedreader
Dax Amin
Dax Amin

Reputation: 537

Java - Reading text file

I have a text file as follow:

Past Dues / Refunds / Subsidy
Arrears / Refunds
Amount
2013.23
Period to which
it  relates
Since OCT-15

Now, how do I extract the data in the next line of "Amount". I have tried it using boolean, checking the above and below line.

Is there any other way to do it.

My code:

boolean isGroup=false;
while(line = br.readline() != null){
    if(line.equals("Amount"){
      isGroup=true;
    }
    if(line.equals("Period to which") && isGroup)
      isGroup=false;
    if(isGroup){
      //read line and check whether it is null or not
      String amount = line;
    }
 }

Please Help. Thanks

Upvotes: 1

Views: 263

Answers (3)

Riz
Riz

Reputation: 1065

this is how you would do @sln answer in java

String text = "Past Dues / Refunds / Subsidy\n" +
"Arrears / Refunds\n" +
"Amount\n" +
"2013.23\n" +
"Period to which\n" +
"it  relates\n" +
"Since OCT-15";

Pattern pattern = Pattern.compile("(?mi)^Amount\\s(?<amount>\\d+\\.\\d{2})");
Matcher matcher =  pattern.matcher(text);

if(matcher.find()){
  String amount = matcher.group("amount");
  System.out.println("amount: "+ amount);
}

Upvotes: 1

xbakesx
xbakesx

Reputation: 13490

Your approach is perfectly fine. You made a little mistake by setting the boolean, then using on the same iteration of the loop.

If you do the following you should be fine:

String amount = "No amount found";
boolean isGroup=false;
while(line = br.readline() != null) {
    // Check all your conditions to see if this is the line you care about
    if(isGroup){
      amount = line;
      isGroup = false; // so you only capture this once
      continue;
    }
    else if (isOtherCondition) {
      // handle other condition;
      isOtherCondition = false; // so you only capture this once
      continue;
    }

    // Check the contents of lines to see if it's one you want to read next iteration
    if(line.equals("Amount"){
      isGroup=true;
    }
    else if (line.equals("Some Other Condition")) {
      isOtherCondition = true;
    }
 }

This is all you need. The break; is just so you don't have to worry about what happens after you grab the amount.

Upvotes: 2

user557597
user557597

Reputation:

If the file is average size, you could use a regex.
Just read in the entire file into a string.
To use a regex it would be something like this.
Result is in capture group 1.

"(?mi)^\\s*Amount\\s+^\\s*(\\d+(?:\\.\\d*)?|\\.\\d+)\\s*$" 

 (?mi)                     # Multi-line mode, case insensitive
 ^                         # Beginning of line
 \s* Amount \s+ 
 ^                         # Beginning of line 
 \s* 
 (                         # (1 start), Numeric value
      \d+ 
      (?: \. \d* )?
   |  \. \d+ 
 )                         # (1 end)
 \s* 
 $                         # End of line

Upvotes: 1

Related Questions