Please match this

[Sherman Willden]

I am trying unsuccessfully to use Java to match a line so I can use particular parts of the line. The String line is:
String line = "-rw-rw-r-- 1 sherman sherman 0 Feb 14 12:17 nonpedalSwing";
I am using Pattern and Matcher. This is an example of how I want to seperate the line so I can use sub 2, sub 3, and sub 5.
String Pattern = "^(-rw-rw-r-- 1 sherman sherman 0)(Feb)(14)( 12:17 )(nonpedalSwing)";
This does not work for me:
String Pattern = "^(-\\w+-\\w+-\\w--\\s\\d\\s\\w+\\s\\w+\\s+\\d\\s)(\\w+)(\\s)(\\d+)(\ \s\\d+:\\d+\\s)(\\w+)";
At the end of this message is the code I am playing with.
How would you do it?

Thanks; Sherman

[Norm Radder]

Also posted here:  https://www.javaprogrammingforums.com/whats-wrong-my-code/43543-please-match.html#post170752

Please read:  https://coderanch.com/wiki/660346/Wiki/Forthright-Cross-Posting-Sites

[Sherman Willden]

Please accept my apologies. I didn't know that cross-posting was such a bad thing. How do I now get an answer to my question?

Thanks for sharing the 7-year old cross posting post.

Sherman

[Ron McLeod]

You would need to remove these 2 characters from the pattern to get a match with the sample data that you included:
^(-\w+-\w+-\w--\s\d\s\w+\s\w+\s+\d\s)(\w+)(\s)(\d+)(\ \s\d+:\d+\s)(\w+)                                                    ^^
And you probably want to remove these brackets so you don't have a capture group containing a single space:
^(-\w+-\w+-\w--\s\d\s\w+\s\w+\s+\d\s)(\w+)(\s)(\d+)(\s\d+:\d+\s)(\w+)                                          ^  ^
Also, you probably want these spaces to be outside of your bracketed capture groups:
^(-\w+-\w+-\w--\s\d\s\w+\s\w+\s+\d\s)(\w+)(\s)(\d+)(\s\d+:\d+\s)(\w+)                                  ^^                ^^       ^^

[Ron McLeod]

Also this part of the pattern which is used to match the file permissions seems a bit fragile:-\w+-\w+-\w--
For example: if the permissions changed from -rw-rw-r-- to -r--r--r-- your pattern would not match.  A safer pattern might be something like:[rwx-]{10}or-[rwx-]{9}

[salvin francis]

Here's my suggestion:
^([-rwx]+?) (\d+?) (\w+?) (\w+?) (\d+?) (.+?) (\d\d \d\d:\d\d) (.+?)$Explanation:
 ^ ... $ start and end of line  ([-rwx]+?) Assuming these are file permissions, we are expecting to find only one of '-' or 'r' or 'w' or 'x'. I think this can be further enhanced The rest are matched based on the spaces and operators that you've already used. Note that the +? operator is lazy quantifier and is based on one ... * matches Assumption: the dates and times are in 2 digit formats strictly.
Let us know if it works

[Carey Brown]

My $.02 - in the beginning...

^([-bcdlnps][-r][-w][-xst][-r][-w][-xst][-r][-w][-xst])\s+

or

^([-bcdlnps]([-r][-w][-xst]){3})\s+

[fred rosenberger]

question:
Is there a reason for doing it this way?  Couldn't you use something like String.split() on whitespace characters, then check the specific array elements for the values?

[Norm Radder]

use particular parts of the line.

Does the OP need to define what those parts are before any code to parse them out can be written?

[Sherman Willden]

Thank you to everone and I really appreciate the time you all took to answer this. I have been using PERL regex since 1993 so I thought this would be an easy step to develop this in Java. Came as a surprise when I couldn't. I am retired and working at the Home Depot and using my off time to improve myself. Again thanks to all. Now how do I mark this as solved and closed?

Sherman

[Norm Radder]

Can you post your solution?

[Sherman Willden]

Thank you Norm. I will but I am working today and tomorrow so it will be Sunday. I appreciate everthing everyone has posted.

[Sherman Willden]

**
 * Capture the day, month, and title of my downloaded
 * steel guitar videos. Later I will separate them
 * into instruction videos and then informative videos.
 * Most of the informative videos can be learning videos
 * as well.
 *
 * TODO: Insert code to open a read-from file which
 * I know how to do, open a write-to file, read a line
 * from the read_from file, obtain the required
 * information from that line, write that line to
 * the write-to file. After all lines have been
 * read and modified then close the read-from file
 * and the write-to file. So far the close file
 * appears to be an automatic feature
 8
 * @author Sherman L. Willden
 * @version 01.1
 */

import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class equalEquals
{
    /**
     * Constructor for objects of class equalEquals
     */
    public static void main(String arg[])
    {
         // The line to perform a regex match against
         String line = "-rw-rw-r-- 1 sherman sherman    0 Feb 14 12:17 nonpedalSwing";
         // String line = "-rw-rw-r-- 1 ";

        // Create a Pattern object
        String pattern = "^([\\-rwx][\\-rwx][\\-rwx]+?[\\s+][\\d+]\\s\\w+\\s\\w+\\s+\\d\\s)(\\w+)(\\s)(\\d+)(\\s\\d+:\\d+\\s)(\\w+)";
        Pattern r = Pattern.compile(pattern);

        // Create a Matcher object
        Matcher m = r.matcher(line);
        if (m.find()) {
            // I want the following information for my csv file which
            // lists the date I found the steel guitar video and the
            // name of the steel guitar video.
            String csvday = m.group(2);
            System.out.println("csv day string = \"" + csvday + "\"");
            String csvmonth = m.group(4);
            System.out.println("csv month string = \"" + csvmonth + "\"");
            String csvtitle = m.group(6);
            System.out.println("csv title string = \"" + csvtitle + "\"");
            System.out.println("Final string to write to the csv file is: ");
            System.out.println("csvday,csvmonth,csvtitle");
        } else {
            System.out.println("No match");
        }

    }
}