CODEWITHSUNDEEP
javaandroidstringarraylist
Dandrews
Dandrews

Reputation: 618

List<string> Item which contains this

I have a list stored as a text file, stored as such

Id;name;function

I have a function that takes the text file and reads it in line by line, each line of text is a new item in a List. Achieved by doing the fallowing.

List<String> list
list.add(line);

What I am trying to do is see if some Id such as "0x0640e331" is in the list. And if it is get everything on the line of text that that Id is found. So the fallowing would happen,

0x0604f552;name0;function
0x0640e331;name1;function
0x0342t521;name2;function

Searching for 0x0640e331 would return, 0x0640e331;name1;function.

Any ideas?

Upvotes: 0

Views: 149

Answers (5)

vijay
vijay

Reputation: 2694

use the startsWith method like this ...

ArrayList<String> queryResult = new ArrayList<String>();
String query = "0x0640e331";
for(String line : list) {
  if(line.startsWith(query)) {
     queryResult.add(line);
  }
}
return queryResult;

This basically checks if a given line in the array-list starts with your query string. If there is more than one line simply add it in another ArrayList and return that as the result.

Upvotes: 1

Mikhail
Mikhail

Reputation: 4223

If you have a large file so you dont want to read it all and lines in your files are sorted by id, you can implement your own binary search algorithm using RandomAccessFile. To read line in the random position, you first select position, and then read forward and backward until a new line symbol.

Upvotes: 0

Lakshmi
Lakshmi

Reputation: 2294

You can use Use Map<String,String> for each element in the list get the string and store it in the map

pseudocode:

for(String item : list) {

String keyName= //use substring to get the id value from the string variable 'item'

map.put(keyName,item);
}
System.out.println(map.get("0x0640e331"));

Upvotes: 0

Joe2013
Joe2013

Reputation: 997

You could use a Map instead of a list. See the sample program given below

import java.util.HashMap;
import java.util.Map;
import java.util.StringTokenizer;

public class TextProgram {
    public static void main(String args[]) {
        String lineArray[] = { "0x0604f552;name0;function",
                "0x0640e331;name1;function", "0x0342t521;name2;function" };
        Map<String, String> map = new HashMap<String, String>();
        StringTokenizer tokenizer = null;
        for (String string : lineArray) {

            tokenizer = new StringTokenizer(string, ";");
            map.put(tokenizer.nextToken(), string);
        }
        System.out.println(map.get("0x0640e331"));
    }
}

Upvotes: 0

rajesh
rajesh

Reputation: 3407

Use Map<String,List>

Store your id as key in the Map and retrieve the values on the key

Upvotes: 0

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