Compare and match readLine() and text in a text file

[huiling25]

I have a text file, i open the file and try to match the contents of the text file to a text. Here's my code:

FileInputStream input = new FileInputStream ("BinaryFp.txt");
BufferedReader br = new BufferedReader(new InputStreamReader(input));
for(int i=1;i<801;i++)
{
pdtNo = br.readLine();
if(pdtNo=="M5250")
System.out.println("true");
else
System.out.println("false");
}
The problem is, i don't know why the answer is always false. There should be 1 match. Is ther any way that i can compare "M5250" with text in the text file?

[r035198x]

I have a text file, i open the file and try to match the contents of the text file to a text. Here's my code:

FileInputStream input = new FileInputStream ("BinaryFp.txt");
BufferedReader br = new BufferedReader(new InputStreamReader(input));
for(int i=1;i<801;i++)
{
pdtNo = br.readLine();
if(pdtNo=="M5250")
System.out.println("true");
else
System.out.println("false");
}
The problem is, i don't know why the answer is always false. There should be 1 match. Is ther any way that i can compare "M5250" with text in the text file?

Always use str.equals(otherString) for comparing strings. Do not use == for that.

[huiling25]

Always use str.equals(otherString) for comparing strings. Do not use == for that.

I tried using str.equals(otherString), but it doesn't works >_<

[r035198x]

I tried using str.equals(otherString), but it doesn't works >_<

Post how you have tried it.

[huiling25]

This is how i use it:

FileInputStream input = new FileInputStream ("BinaryFp.txt");
BufferedReader br = new BufferedReader(new InputStreamReader(input));
for(int i=1;i<801;i++)
{
pdtNo = br.readLine();
if(pdtNo.equals("M5250"))
System.out.println("true");
else
System.out.println("false");
}

But the result is still "false".

[r035198x]

This is how i use it:

FileInputStream input = new FileInputStream ("BinaryFp.txt");
BufferedReader br = new BufferedReader(new InputStreamReader(input));
for(int i=1;i<801;i++)
{
pdtNo = br.readLine();
if(pdtNo.equals("M5250"))
System.out.println("true");
else
System.out.println("false");
}

But the result is still "false".

Try

 
for(int i=1;i<801;i++)
{
pdtNo = br.readLine();
System.out.println(pdtNo);
}
 

And see what is being read from the file.

[huiling25]

Try

 
for(int i=1;i<801;i++)
{
pdtNo = br.readLine();
System.out.println(pdtNo);
}
 

And see what is being read from the file.

I tried that too, all the text in the text file is printed out correctly, i just cannot match the text in the file to "M5250".

[r035198x]

I tried that too, all the text in the text file is printed out correctly, i just cannot match the text in the file to "M5250".

When you printed out the lines, was there a line with "M5250" only and no leading spaces or extra spaces after that? The comparison will only match if there is a line that appears exactly as "M5250".

If you are sure such a line exists and with no extra spaces, then you may want to post the textfile as well so we can really see if you are right.

[huiling25]

When you printed out the lines, was there a line with "M5250" only and no leading spaces or extra spaces after that? The comparison will only match if there is a line that appears exactly as "M5250".

If you are sure such a line exists and with no extra spaces, then you may want to post the textfile as well so we can really see if you are right.

There are spaces. I had done another java file to create that text file (BinaryFp.txt). So now, i'm using java to read this text file i have created. Is there any way which i can remove all the spaces, so that i can compare?

[r035198x]

There are spaces. I had done another java file to create that text file (BinaryFp.txt). So now, i'm using java to read this text file i have created. Is there any way which i can remove all the spaces, so that i can compare?

Try str.trim();

[huiling25]

Try str.trim();

I tried "str.trim();", but there are still many spaces when i print it out. And therefore, the result is still false. Here's my code:

for(int i=1;i<801;i++)
{
pdtNo = br.readLine();
String no = pdtNo.trim();
System.out.println(pdtNo);
if(no.equals("M5250"))
System.out.println("true");
else
System.out.println("false");
}

[r035198x]

I tried "str.trim();", but there are still many spaces when i print it out. And therefore, the result is still false. Here's my code:

for(int i=1;i<801;i++)
{
pdtNo = br.readLine();
String no = pdtNo.trim();
System.out.println(pdtNo);
if(no.equals("M5250"))
System.out.println("true");
else
System.out.println("false");
}

What is the output with

 
for(int i=1;i<801;i++)
{
pdtNo = br.readLine();
String no = pdtNo.trim();
System.out.println(no);// Print out no instead of pdtNo
}
 

Where are the spaces?

[huiling25]

What is the output with

 
for(int i=1;i<801;i++)
{
pdtNo = br.readLine();
String no = pdtNo.trim();
System.out.println(no);// Print out no instead of pdtNo
}
 

Where are the spaces?

Thanx for your help ^-^. It finally works now.

[r035198x]

Thanx for your help ^-^. It finally works now.

Welcome. Also have a look at http://java.sun.com/j2se/1.4.2/docs/...ng/String.html