getting two consicutive value from file in java -
i working csv file, , want extract 2 values in specific positions each , every row.
the csv input file looks this:
a, b, c, d 12,32,45,76 23,45,77,56 32,34,49,28 73,92,26,68 73,36,77,26 for example want 2 consecutive values 3rd position (column c) every row @ same time, (45, 77), (49, 26), (77, ???)…
after getting 2 values, want calculation on them , store them back.i working on []2x1 size matrix multiplication. reason need 2 consecutive value @ time.
package rotation.pkg45;import java.io.file; import java.io.filenotfoundexception; import java.util.scanner; import java.util.logging.level; import java.util.logging.logger; import java.io.filewriter; import java.io.*; import java.text.decimalformat; import java.util.arraylist; import java.util.collections; import java.util.list; import java.util.listiterator; public class rotation45 { public static void main(string[] args) throws ioexception { string filename = "bank-full2.csv"; file file = new file(filename); bufferedwriter writer = null; try { writer = new bufferedwriter(new filewriter("bank2test1.csv")); double a1 = 0.866025; double a2 = 0.5; double a3 = -0.5; double a4 = 0.866025; double b1; double b2; double c1; double c2; scanner inputstream = new scanner(file); inputstream.next(); scanner inputstreamm = new scanner(file); inputstreamm.next(); while (inputstreamm.hasnext()) { string data = inputstreamm.next(); //read each line , store in data string[] values = data.split(","); //every line splited " ; " , store each attribute in string list double first = double.parsedouble(values[2]); /*nosuchelementexception*/string data1 = inputstreamm.next(); //read comming nextline second value , store in data1 string[] values1 = data1.split(","); //inputstream.next(); double second = double.parsedouble(values1[2]); c1 = ((a2 * second) + (a1 * first)); c2 = ((a3 * first) + (a4 * second)); values1[2] = string.valueof(c2); values[2] = string.valueof(c1); stringbuilder sb = new stringbuilder(); //string newdata = sb.tostring(); (int = 0; < values.length; i++) { sb.append(values[i]); if (i < values.length - 1) { sb.append(","); } } sb.append("\n"); (int = 0; < values1.length; i++) { sb.append(values1[i]); if (i < values.length - 1) { sb.append(","); } } //get new string //system.out.println(sb.tostring()); writer.write(sb.tostring()+"\n"); } writer.close(); inputstreamm.close(); } catch(filenotfoundexception ex) { logger.getlogger(rotation45.class.getname()).log(level.severe, null, ex); } } i getting error nosuchelement exception @ mention in code...
i solved issue using bufferedreader instead of scanner read datas. since code trying read whole line via scanner , split it, can in easier way using bufferedreaderand calling readline()method.
so changes brought code replacement of use of scanner use of bufferedreader. i have not checked computing seems me working fine.
here image of result get:
also since while loop based on scanner changed too.the while loop using checks both lines not null (reading them @ same time while condition being assessed)
the last point regarding code on bufferedwriter have newline()method inserts portable equivalent of line skeep (the \n in code)
here code. execute , check working fine.
public class rotation45 { public static void main(string[] args) throws ioexception { string filename = "bank-full2.csv"; file file = new file(filename); bufferedwriter writer = null; bufferedreader reader = null; try { reader = new bufferedreader(new filereader(file)); writer = new bufferedwriter(new filewriter("bank2test1.csv")); double a1 = 0.866025; double a2 = 0.5; double a3 = -0.5; double a4 = 0.866025; double b1; double b2; double c1; double c2; string line1= null; string line2 = null; // skeeps head line reader.readline(); string currentline = null; while ( ((line1 = reader.readline())!= null) && ((line2 = reader.readline()) != null) ) { string[] values = line1.split(","); double first = double.parsedouble(values[2]); string[] values1 = line2.split(","); double second = double.parsedouble(values1[2]); c1 = ((a2 * second) + (a1 * first)); c2 = ((a3 * first) + (a4 * second)); values1[2] = string.valueof(c2); values[2] = string.valueof(c1); stringbuilder sb = new stringbuilder(); (int = 0; < values.length; i++) { sb.append(values[i]); if (i < values.length - 1) { sb.append(","); } } sb.append("\n"); (int = 0; < values1.length; i++) { sb.append(values1[i]); if (i < values.length - 1) { sb.append(","); } } writer.write(sb.tostring()); writer.newline(); } writer.flush(); writer.close(); reader.close(); } catch(filenotfoundexception ex) { logger.getlogger(rotation45.class.getname()).log(level.severe, null, ex); } } }
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