Please help

Question about the task

R or L

Java Syntax, Level 7, Lesson 9

Resolved

I think the problem is when I remove "r" words, it jumps a word. Anyone know how to overcome this?

1. Create a list of words and populate it yourself.
2. The fix method should:
2.1. remove all words containing the letter "r" from the list
2.2. duplicate all words containing the letter "l".
2.3. if a word contains both "r" and "l", then leave it unchanged.
2.4. don't do anything to other words.

For example:
rose lyre love

Output:
lyre love love

Requirements:

The program must not read data from the keyboard.
The fix method should remove all words containing the letter "r" from the list. There is an exception: words containing both "r" and "l" should be left alone.
The fix method must duplicate words containing the letter "l" (add another instance of this word to the list). There is an exception: words containing both "l" and "r" should not be duplicated.
The fix method should not do anything with words that contain both "l" and "r".
The fix method should not do anything with words that don't contain either "l" or "r".

package com.codegym.task.task07.task0716; import java.util.ArrayList; /* R or L */ public class Solution { public static void main(String[] args) throws Exception { ArrayList<String> list = new ArrayList<String>(); list.add("rose"); // 0 list.add("love"); // 1 list.add("lyre"); // 2 list = fix(list); for (String s : list) { System.out.println(s); } } public static ArrayList<String> fix(ArrayList<String> list) { // write your code here for (int i = 0; i < list.size(); ) { String s = list.get(i); if (s.contains("l")) { if (s.contains("r")) { i++; } else if (s.contains("l")) { list.add(i + 1, s); } i++; } else if (s.contains("r")) { list.remove(i); i++; } } return list; } }

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Agent Smith

Level 38

8 August 2020, 12:39

You are overcomplicating things. First of all, best to do i++ inside for loop, otherwise you are duplicating code a lot. When you are checking if the word contains both "l" and "r" all you really want to do is jump to the next loop iteration. This can be done like this:

if (s.contains("l")) {
    if (s.contains("r")) continue;
    // no need to add any additional if checks here, because the
    // following code will only execute when there is only "l"
    list.add(i + 1, s);
}

Another issue you might run into is this: you are running a loop based on the list size, but inside that loop the size of the list might change (by removing or adding new elements) this might cause problems and such practice should be avoided. Consider using two lists instead of one.

Jan Elšík

Level 41 , Prague, Czech Republic

8 August 2020, 13:18

Awesome, that solved it! Many thanks :)

Agent Smith

Level 38

8 August 2020, 13:32

Please don't forget to mark it as "solved" then. ;)