Deleting first line off file
Hello,
I want to remove the first line of a file. Is there any way to do that
without reading the whole file and putting it in a huge string?
Something like setting the "begining of file marker" (does that
exist?). I've looked in the "advanced file function" and can't find a
way to do it.
Any suggestion?
Thanks a lot!!
Vincent
I don't see any Read File by Lines vi in LV7.1. Maybe it exists in LV 8. However there is a Read Lines from File vi but it does not produce an array of lines (at least not in LV 7.1). You can use the Read Lines from File vi and set the number of lines to 1. The output mark after read is now set to point to the second line. You can use this as an input to start of read offset on your next read call. This vi will open the file, read, then close the file. Calling it a second time will open the file again, read, then close again.
Another way is to open the file using Open/Create/Replace File. Then use Read File and set the Line Mode input to True. This will read the first line. A second Read File call will then begin reading at the second line without having to wire any offsets. After reading all that you want, you close the file. One open, several reads, one close. This is more efficient.
Message Edited by tbob on 03-06-2007 03:03 PM
- tbob
Inventor of the WORM Global
Attachments:
ReadLines.png 4 KB
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using System.Collections.Generic;
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using System.Diagnostics;
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How to delete the specified line in file?
How to delete the specified line in file? In case of deleting a specified line in a file, how to do?
Line 1
Line 2
Line 3
Line 4
Line 5
The case is a file including the above content. Now I wanna to delete the "Line 3" and how to realize the action in Java?An alternative solution can be :
import java.io.LineNumberReader;
import java.io.IOException;
import java.io.File;
import java.io.FileReader;
import java.io.BufferedWriter;
import java.io.FileWriter;
import java.io.PrintWriter;
public class LineDeleter {
public static void main(String args[]){
try {
//suppose you want to delete line 3
int lineToBeDeleted = 3;
File f = new File("line.txt");
long fileSize = f.length();
//Wrap the FileReader with a LineNumberReader. It will help you
//identify the lines.
LineNumberReader lnr = new LineNumberReader( new FileReader(f));
//Wrap the FileWriter object with BufferedWriter object. Create it with the buffersize
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BufferedWriter bw = new BufferedWriter(new FileWriter(new File("line1.txt")),(int)fileSize);
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PrintWriter pw = new PrintWriter(bw);
String s=null;
while ( (s=lnr.readLine())!=null ){
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pw.flush();
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I hope this helps.Good luck!!!!!! -
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Trying to omit first line of CSV file (the header)
Hello everybody,
Newbie here havin a lil problem. I have this program below that reads in a CSV file. My test CSV file has the follow structure:
ID, LastName, FirstName, Phone, Email,
2345, Yez, Wei do, 456-789-0123, [email protected],
2744, Avanto, Aldo, 562-593-6500, [email protected],
1212, Dewy, Cheatem, 123-456-7890, [email protected],
1234, No, Wei Foo, 123-456-7890, [email protected],
The first line is my header. (here is the heart of my problem)
I have the program reading in the file and the it sorts it. The problem i have is that the first line, my header gets sorted with everything else. Here is my feable attempt with resulting error:
import java.io.*;
import java.util.*;
public class File2Array {
public static void main(String[] args)
File file = new File("person_test1.csv"); //File to read in
ArrayList persons = (ArrayList) getPersons(file); //call to arraylist
Collections.sort(persons);
for (Iterator i = persons.iterator(); i.hasNext(); )
System.out.println(i.next());
public static List getPersons(File file)
//NEW PIECE OF CODE boolean first = true;
ArrayList persons = new ArrayList();
try {
BufferedReader buf = new BufferedReader(new FileReader(file));
while (buf.ready()) {
String line = buf.readLine();
//NEW PIECE OF CODE
while( ( line = buf.readLine() ) != null )
if( first )
first = false; continue;
//ORIGINAL IF
// if (!line.equals("") )
//NEW IF
if (line != null && !line.equals("") )
//END OF NEW CODE
StringTokenizer tk = new StringTokenizer(line, ",");
ArrayList params = new ArrayList();
while (tk.hasMoreElements())
params.add(tk.nextToken());
Person p = new Person(
(String) params.get(0),
(String) params.get(1),
(String) params.get(2),
(String) params.get(3),
(String) params.get(4));
persons.add(p);
} catch (IOException ioe)
System.err.println(ioe);
return persons;
class Person implements Comparable
private String ID;
private String LastName;
private String FirstName;
private String Phone;
private String Email;
public Person(
String ID,
String LastName,
String FirstName,
String Phone,
String Email)
if (FirstName==null || LastName==null)
throw new NullPointerException();
this.ID = ID;
this.LastName = LastName;
this.FirstName = FirstName;
this.Phone = Phone;
this.Email = Email;
public String toString()
StringBuffer sb = new StringBuffer ();
sb.append( ID );
sb.append(" ");
sb.append( LastName );
sb.append(" ");
sb.append( FirstName );
sb.append(" ");
sb.append( Phone );
sb.append(" ");
sb.append( Email );
sb.append(" ");
return sb.toString();
public boolean equals(Object o)
if (!(o instanceof Person))
return false;
Person p = (Person)o;
return p.FirstName.equals(FirstName) &&
p.LastName.equals(LastName);
public int hashCode()
return 31*FirstName.hashCode() + LastName.hashCode();
public int compareTo(Object o)
Person p = (Person)o;
int lastCmp = LastName.compareTo(p.LastName);
return (lastCmp!=0 ? lastCmp :
FirstName.compareTo(p.FirstName));
this code compiles and runs but does not produce any output and I don't understand why.
Question: What is the proper way to have the code omit the first line of a CSV file??
By the way I do have another file called person.java that goes with this but I didn't think I had to post it.
Also am I posting correctly? Am I putting in too much code??
Than you!!Hot diggity! jverd,
I got it to work!! here's what I did all thanks to you :-)
ArrayList persons = new ArrayList();
try {
BufferedReader buf = new BufferedReader(new FileReader(file));
//read through file and populate array
//while (buf.ready()) {
String firstline = buf.readLine(); //gets header, renamed line to firstline
String line; //added this line
System.out.println(firstline); //added this to print out firstline
//try this
while( ( line = buf.readLine() ) != null )
/*{ //commented out this portion
if( first )
first = false; continue;
//end try this
//if (line != null && !line.equals("") ) //down to here
if (!line.equals("") ) //added this
StringTokenizer tk = new StringTokenizer(line, ",");
ArrayList params = new ArrayList();
while (tk.hasMoreElements())
params.add(tk.nextToken());
Person p = new Person(
(String) params.get(0),
(String) params.get(1),
(String) params.get(2),
(String) params.get(3),
(String) params.get(4));
persons.add(p);
} -
The first line in a file is supressed
hi all,
i have a really weird problem.
i have a file with a lot of data and i am using a file adapter with file content conversion to parse it.
the file adapter is a sender one.
the problem come when i do read the file and then it ignore the first line of the file.
all the lines from the second one forward is shown in SXMB_MONI but the first line of the file isn't.
i can't seem to figure out what the problem is, i tryed looking for some kind of attribute in the file adpater but had no luck.
could you please help me?
btw,
the file structure is: header,1,body1,<wildcard>,body2,<wildcard>
Edited by: Roi Grossfeld on Oct 29, 2008 4:24 PMRecordset Structure: H1,1,B1,<wildcard>,B2,<wildcard>
Key Field Name: RecordType
H1.fieldFixedLengths 6,2,8,1,1,3,30,5
H1.fieldNames FileNo,RecordType,TransmissionDate,Car_Truck,BU,MD,FileName,Count
H1.keyFieldValue H1
B1.fieldFixedLengths 6,2,10,27,8,8,4,5,3,11,9,9,11,11,9,9,7,9,11
B1.fieldNames FileNo,RecordType,InvoiceNumber,VesselName,MMSEShipmentDate,PlanArrivalDate,DeliveryPlace,Units,Currency,ModelPriceAmount,OptionPriceAmount,ColourPriceAmount,REPriceAmount,TotalPriceAmount,FreightChargeAmount,InsuranceFeeAmount,MiscellaneousAmount,VATAmount,GrandTotalAmount
B1.keyFieldValue B1
B2.fieldFixedLengths 6,2,10,12,12,12,5,6,12,3,3,3,4,17,7,7,12,8,5,3,9,7,7,9,9,7,9,4,20
B2.fieldNames FileNo,RecordType,InvoiceNumber,MDOrderNumber,MMSEOrderNumber,MMSECaseNumber,ModelYear,BodyType,Model,ExteriorColourCode,InteriorTrimColourCode,OptionCode,RearEquipment,VehicleIdentificationNumber,ChassisModel,CSequenceNumber,EngineModel,ESequenceNumber,KeyNumber,Currency,UnitModelPrice,UnitOptionPrice,UnitColourPrice,UnitRearEquipmentPrice,UnitTotalPrice,UnitVATAmount,UnitTotalVAT,VATRate,VATNumber
B2.keyFieldValue B2
ignoreRecordsetName true
Edited by: Roi Grossfeld on Oct 29, 2008 4:39 PM
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