Java read file and store text in an array
268,391
Solution 1
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);
}
}
}
Solution 2
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(", ");
Solution 3
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]);
Solution 4
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]);
}
}
Author by
word word
Updated on March 02, 2020Comments
-
word word about 4 years
I know how to read a file with
Java
usingScanner
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