How to extract a integer from a binary string and save it in a matrix?

Question

I have a properties file that contains this information:

info.row1=1100011 info.row2=1000001 info.row3=0001000 info.row4=0011100 info.row5=0001000 info.row6=1000001 info.row7=1100011

Also I have a matrix like this

info = new int[7][7];

I want to save each int number in a part of the matrix, like this:

 --------------- |1|1|0|0|0|1|1| --------------- |1|0|0|0|0|0|1| --------------- |0|0|0|1|0|0|0| --------------- |0|0|1|1|1|0|0| --------------- |0|0|0|1|0|0|0| --------------- |1|0|0|0|0|0|1| --------------- |1|1|0|0|0|1|1| ---------------

How can I do that? I have this code that works well until now, I just need to save that info in the matrix.

 private void startInfo(Properties data) { info = new int[7][7]; for(int i = 0; i < 7; i++) { for(int j = 0; j < 7; j++) { String estate = data.getProperty( "info.row" +i ); info[i][j] = ???????????; } } }

Reut Sharabani · Accepted Answer · 2015-11-14 22:34:23Z

2

Read the data once per row and use the String.charAt function to map to integers:

private void startInfo(Properties data) { info = new int[7][7]; for (int i = 0; i < 7; i++) { // only read once per row String estate = data.getProperty( "info.row" +i ); for (int j = 0; j < 7; j++) { // map '0' to 0, anything else to '1' info[i][j] = estate.charAt(j) == '0' ? 0 : 1; } } }

answered Nov 14, 2015 at 22:34

Reut Sharabani

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5 Comments

zipzit Over a year ago

clever using the if statement to do the 'conversion' to integers... Nicely done!

Paul Boddington Over a year ago

@zipzit There isn't an if statement there! Was that comment meant for me?

zipzit Over a year ago

no, comment for Reut... My bad, not a pure if statement, he used the ternary operator to perform the if function. Thats not a tool most folks reach for first. Paul, I would have done it exactly the way you did it.

Jhon House Over a year ago

Thanks for the response, altough I get a nullPointerException I dont know why. I need to save it as an integer in order to compare it later.

Paul Boddington Over a year ago

@zipzit Fair enough :)

Elliott Frisch · Accepted Answer · 2015-11-14 22:43:44Z

You could use Character.digit(char, int) to perform the int conversion. Something like

info = new int[7][7]; for (int i = 0; i < info.length; i++) { String estate = data.getProperty(String.format("info.row%d", i + 1)); char[] line = estate.toCharArray(); for (int j = 0; j < line.length; j++) { info[i][j] = Character.digit(line[j], 10); } }

Yassin Hajaj · Accepted Answer · 2015-11-14 22:44:10Z

Here is a solution using RegExs and a loop

Matcher m = Pattern.compile("=\\d*").matcher("info.row1=1100011 info.row2=1000001 info.row3=0001000 info.row4=0011100 info.row5=0001000 info.row6=1000001 <info.row7=1100011"); int[][] info = new int[7][7]; int counter = 0; while (m.find()){ String s = m.group(0).substring(1); for (int i = 0 ; i < s.length() ; i++){ info[counter][i] = s.charAt(i); } counter++; }

Jhon House · Accepted Answer · 2015-11-14 23:01:17Z

Thanks to all for the answer, you all resolved my doubt. Although, what no one realized (including me) is that my properties data started in 1, for example the first line was "info.row1", so when we started the first "for" in 0, we were searching for something that didnt exist, and a nullpointerexception error was caused. So the solution is to add 1 to i and problem solved. THANKS

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