I am trying to write the data from a Text file into an ArrayList. I have the code below. The lines in the text file have this format:
Id
Car Manufacturer
Car Type
Colour
*blank line*
For Example:
21
Vauxhall
Corsa
red
19
Vauxhall
Corsa
blue
18
Vauxhall
Corsa
White
It does this 24 times, displays the information correctly when run, but the size of the list is "1". I was wondering if it is possible to split up each car by the blank space so they can be individually separated.
You are currently only reading in the file in a value by value basis. It might be worth considering changing to reading the file in a line by line basis.
So you could use the method like so:
String lineValue = "";
while (inFile1.hasNextLine()) {
lineValue = inFile1.nextLine();
if(lineValue.isEmpty()) {
temps.add(token1);
token1 = "";
} else {
token1 += lineValue;
}
}
This would allow it to add multiple separate strings to the list. You may need to include a blank space at the end of the file to add the last string though, or add an extra bit of code to check if it's at the end of the file.
I hope, that this code will rsolve your problem:
public static void main(String[] args) throws IOException {
FileReader inFile1 = new FileReader(new File("example.txt"));
List<String> temps = new ArrayList<String>();
BufferedReader reader = new BufferedReader(inFile1);
String line = "";
String propertyText = "";
while ((line = reader.readLine()) != null) {
if(line.length() > 0) {
propertyText += line + "\n";
}else{
temps.add(propertyText);
propertyText = "";
}
}
temps.add(propertyText);
inFile1.close();
String[] tempsArray = temps.toArray(new String[0]);
for (String s : tempsArray) {
System.out.println(s);
}
// this will print the size of this list
int retval = temps.size();
System.out.println("Size of list = " + retval);
}
Agree with @Thomas. Follow the code:
Scanner inFile1 = new Scanner(new File("example.txt")); // don't use any delimiter
List<String> temps = new ArrayList<String>();
String tokenTemp= "";
while (inFile1.hasNextLine()) {
tokenTemp = inFile1.nextLine();
if(tokenTemp.isEmpty()){
temps.add(token1);
token1="";
}
else token1 += tokenTemp+" ";
}
Here every line inserted in temps list.
This is because the entire file is read at once due to the regex. I modified your code like this,
Scanner inFile1 = new Scanner(new File("example.txt"));
//.useDelimiter(",\\s*");
List<String> temps = new ArrayList<String>();
while (inFile1.hasNext()) {
token1 = inFile1.nextLine();
temps.add(token1);
}
And it works. If every new value is printed in a new line, you can use nextLine() method of Scanner class.
From what You have posted, I understand that you differentiate the details of each car with a blank line, you can you the following regex pattern to split whenever two new line characters occur (one for the end of line and one for the blank line)
20
Vauxhall
Corsa
red (newline1)
(newline2)
19
Vauxhall
Corsa
blue(newline1)
(newline2)
18
Vauxhall
Corsa
White
This should do it:
Scanner inFile1 = new Scanner(new File("cars.txt")).useDelimiter("(\r\n){2,}");
,\s*, i.e. a comma followed by any whitespace, but your description doesn't mention that comma.id,car manufacturerand so on in one line for each car or in separate lines?