I know how to read a file with Java using Scanner and File IOException, but the only thing I don't know is how to store the text in the files as an array.
Here is a snippet of my code:
public static void main(String[] args) throws IOException{
// TODO code application logic here
// // read KeyWestTemp.txt
// create token1
String token1 = "";
// for-each loop for calculating heat index of May - October
// create Scanner inFile1
Scanner inFile1 = new Scanner(new File("KeyWestTemp.txt"));
// while loop
while(inFile1.hasNext()){
// how can I create array from text read?
// find next line
token1 = inFile1.nextLine();
Here is what my KeyWestTemp.txt file contains:
70.3, 70.8, 73.8, 77.0, 80.7, 83.4, 84.5, 84.4, 83.4, 80.2, 76.3, 72.0
This question is related to
java
arrays
file-io
storing-data
Stored as strings:
public class ReadTemps {
public static void main(String[] args) throws IOException {
// TODO code application logic here
// // read KeyWestTemp.txt
// create token1
String token1 = "";
// for-each loop for calculating heat index of May - October
// create Scanner inFile1
Scanner inFile1 = new Scanner(new File("KeyWestTemp.txt")).useDelimiter(",\\s*");
// Original answer used LinkedList, but probably preferable to use ArrayList in most cases
// List<String> temps = new LinkedList<String>();
List<String> temps = new ArrayList<String>();
// while loop
while (inFile1.hasNext()) {
// find next line
token1 = inFile1.next();
temps.add(token1);
}
inFile1.close();
String[] tempsArray = temps.toArray(new String[0]);
for (String s : tempsArray) {
System.out.println(s);
}
}
}
For floats:
import java.io.File;
import java.io.IOException;
import java.util.LinkedList;
import java.util.List;
import java.util.Scanner;
public class ReadTemps {
public static void main(String[] args) throws IOException {
// TODO code application logic here
// // read KeyWestTemp.txt
// create token1
// for-each loop for calculating heat index of May - October
// create Scanner inFile1
Scanner inFile1 = new Scanner(new File("KeyWestTemp.txt")).useDelimiter(",\\s*");
// Original answer used LinkedList, but probably preferable to use ArrayList in most cases
// List<Float> temps = new LinkedList<Float>();
List<Float> temps = new ArrayList<Float>();
// while loop
while (inFile1.hasNext()) {
// find next line
float token1 = inFile1.nextFloat();
temps.add(token1);
}
inFile1.close();
Float[] tempsArray = temps.toArray(new Float[0]);
for (Float s : tempsArray) {
System.out.println(s);
}
}
}
I use this method:
import java.util.Scanner;
import java.io.File;
import java.io.FileNotFoundException;
public class TEST {
static Scanner scn;
public static void main(String[] args) {
String text = "";
try{
scn = new Scanner(new File("test.txt"));
}catch(FileNotFoundException ex){System.out.println(ex.getMessage());}
while(scn.hasNext()){
text += scn.next();
}
String[] arry = text.split(",");
//if need converting to float do this:
Float[] arrdy = new Float[arry.length];
for(int i = 0; i < arry.length; i++){
arrdy[i] = Float.parseFloat(arry[i]);
}
System.out.println(Arrays.toString(arrdy));
}
}
Just read the whole file into a StringBuilder, then split the String by dot following a space. You will get a String array.
Scanner inFile1 = new Scanner(new File("KeyWestTemp.txt"));
StringBuilder sb = new Stringbuilder();
while(inFile1.hasNext()) {
sb.append(inFile1.nextLine());
}
String[] yourArray = sb.toString().split(", ");
int count = -1;
String[] content = new String[200];
while(inFile1.hasNext()){
content[++count] = inFile1.nextLine();
}
EDIT
Looks like you want to create a float array, for that create a float array
int count = -1;
Float[] content = new Float[200];
while(inFile1.hasNext()){
content[++count] = Float.parseFloat(inFile1.nextLine());
}
then your float array would look like
content[0] = 70.3
content[1] = 70.8
content[2] = 73.8
content[3] = 77.0 and so on
I have found this way of reading strings from files to work best for me
String st, full;
full="";
BufferedReader br = new BufferedReader(new FileReader(URL));
while ((st=br.readLine())!=null) {
full+=st;
}
"full" will be the completed combination of all of the lines. If you want to add a line break between the lines of text you would do
full+=st+"\n";
while(inFile1.hasNext()){
token1 = inFile1.nextLine();
// put each value into an array with String#split();
String[] numStrings = line.split(", ");
// parse number string into doubles
double[] nums = new double[numString.length];
for (int i = 0; i < nums.length; i++){
nums[i] = Double.parseDouble(numStrings[i]);
}
}
If you don't know the number of lines in your file, you don't have a size with which to init an array. In this case, it makes more sense to use a List :
List<String> tokens = new ArrayList<String>();
while (inFile1.hasNext()) {
tokens.add(inFile1.nextLine());
}
After that, if you need to, you can copy to an array :
String[] tokenArray = tokens.toArray(new String[0]);
Source: Stackoverflow.com