StackOverflow2013

Note that there are some explanatory texts on larger screens.

plurals

POSort one column of data in a csv file in ascending order in java
text
Body
copied!<pre><code>import java.io.*; import java.util.*; public class Sort { public static void main(String[] args) throws Exception { BufferedReader reader = new BufferedReader(new FileReader("data1.csv")); Map<String, String> map=new TreeMap<String, String>(); String line=""; while((line=reader.readLine())!=null){ map.put(getField(line),line); } reader.close(); FileWriter writer = new FileWriter("sorted_numbers.txt"); for(String val : map.values()){ writer.write(val); writer.write('\n'); } writer.close(); } private static String getField(String line) { return line.split(",")[0];//extract value you want to sort on } } </code></pre> <p>Hia I am trying to read a unsorted file and get Java to sort one column of the csv data file and print those results in a new file. I borrowed this solution whilst I was searching on this website because I think it is ideal for what I am trying to acomplish. I have a 282 rows of data in the form of </p> <pre><code>UserID, Module, Mark Ab004ui, g46PRo, 54 cb004ui, g46GRo, 94 gy004ui, g46GRo, 12 ab004ui, g46PRo, 34 </code></pre> <p>this is in the csv file. when I use the above code it only gives me one line in the sorted_marks.txt, like this</p> <pre><code>ab004ui, g46PRo, 34 </code></pre> <p>and I believe it wasnt even sorted.</p> <p>I want all the results from the new file to be sorted based on their userID and nothing else but I can't seem to get it to work, please any help would be greatful</p>

Querying!

Guidance

An individual column

Larger individual text columns get their own page to allow for proper reading.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload