wordsWithoutList challenge

Don't bother with an array right now; the method returns a List, so you might as well build the list directly, instead of building an array and converting it to a list at the end.

Don't bother with an array right now; the method returns a List, so you might as well build the list directly, instead of building an array and converting it to a list at the end.

i wonder why above array approach do not work. As i am working lot with arrays now and not started with collection challenges yet on coding bat

public List wordsWithoutList(String[] words, int len) {
 int count=0;
 int origlen=words.length;
 int newLen=origlen-len;
 String[] arr=new String[newLen];
 List a1 = new ArrayList();
     
for(int i=len-1;i<newLen;i++){
 // arr[i]=words[i];
   a1.add("words[i]");
     // a1.add("Mahnaz");
     // a1.add("Ayan");
  
 
}
return a1;
}

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above gives below errors

Expected	Run		
wordsWithoutList(["a", "bb", "b", "ccc"], 1) → ["bb", "ccc"]	["words[i]", "words[i]", "words[i]"]	X	
wordsWithoutList(["a", "bb", "b", "ccc"], 3) → ["a", "bb", "b"]	[]	X	
wordsWithoutList(["a", "bb", "b", "ccc"], 4) → ["a", "bb", "b", "ccc"]	[]	X	
wordsWithoutList(["xx", "yyy", "x", "yy", "z"], 1) → ["xx", "yyy", "yy"]	["words[i]", "words[i]", "words[i]", "words[i]"]	X	
wordsWithoutList(["xx", "yyy", "x", "yy", "z"], 2) → ["yyy", "x", "z"]	["words[i]", "words[i]"]	X	

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please advise

I agree with rrz. Start over with your pseudocode and try again. What you have on line 10 is definitely not going to work; you're adding the string "words[i]" to your list over and over.

i see i was surely misunderstood challenge



Given an array of strings, return a new List (e.g. an ArrayList) where all the strings of the given length are omitted. See wordsWithout() below which is more difficult because it uses arrays.

wordsWithoutList(["a", "bb", "b", "ccc"], 1) → ["bb", "ccc"]//i ws ommitting first element which is wrong
wordsWithoutList(["a", "bb", "b", "ccc"], 3) → ["a", "bb", "b"]
wordsWithoutList(["a", "bb", "b", "ccc"], 4) → ["a", "bb", "b", "ccc"]

how to add each array element to list?

I think we shouldn't tell you that, since that's most of the challenge right there. You are already using List.add(), but you're passing a string literal to it. What else can you pass to it?

i see your point. i can add array element directly rather than string literal

public List wordsWithoutList(String[] words, int len) {
 List a1 = new ArrayList();
for(int i=len-1;i<words.length;i++){
   if(words[i].length()!=len){
   a1.add(words[i]);
   }
}
return a1;
}

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i am failing 2 tests where length is greater?

Expected      Run            
wordsWithoutList(["a", "bb", "b", "ccc"], 1) → ["bb", "ccc"]      ["bb", "ccc"]      OK      
wordsWithoutList(["a", "bb", "b", "ccc"], 3) → ["a", "bb", "b"]      ["b"]      X      
wordsWithoutList(["a", "bb", "b", "ccc"], 4) → ["a", "bb", "b", "ccc"]      ["ccc"]      X      
wordsWithoutList(["xx", "yyy", "x", "yy", "z"], 1) → ["xx", "yyy", "yy"]      ["xx", "yyy", "yy"]      OK      
wordsWithoutList(["xx", "yyy", "x", "yy", "z"], 2) → ["yyy", "x", "z"]      ["yyy", "x", "z"]      OK      

Take a closer look at where you're starting your loop.

public List wordsWithoutList(String[] words, int len) {
 List a1 = new ArrayList();
for(int i=0;i<words.length;i++){
   if(words[i].length()!=len){
   a1.add(words[i]);
   }
}
return a1;
}

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oops my mistake while modifying old code. now passing all tests. any improvement or alaternate approaches for this?

Expected      Run            
wordsWithoutList(["a", "bb", "b", "ccc"], 1) → ["bb", "ccc"]      ["bb", "ccc"]      OK      
wordsWithoutList(["a", "bb", "b", "ccc"], 3) → ["a", "bb", "b"]      ["a", "bb", "b"]      OK      
wordsWithoutList(["a", "bb", "b", "ccc"], 4) → ["a", "bb", "b", "ccc"]      ["a", "bb", "b", "ccc"]      OK      
wordsWithoutList(["xx", "yyy", "x", "yy", "z"], 1) → ["xx", "yyy", "yy"]      ["xx", "yyy", "yy"]      OK      
wordsWithoutList(["xx", "yyy", "x", "yy", "z"], 2) → ["yyy", "x", "z"]      ["yyy", "x", "z"]      OK      

All Correct

do codingbat allow generics?

public List wordsWithoutList(String[] words, int len) {
 List<String> a1 = new ArrayList<String>();
for(int i=0;i<words.length;i++){
   if(words[i].length()!=len){
   a1.add(words[i]);
   }
}
return a1;
}

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you mean like above? it passed all tests

In Java 8, you might use a stream, in place of the loop. I think their site doesn't allow Java 8 features, though

how to use this? i can try in eclipse

Streams are a bit much to get into here, I think.

import java.util.ArrayList;
import java.util.List;

public class WordsWithoutList {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		String[] ar = { "a", "bb", "b", "ccc" };
		System.out.println("wordsWithoutList value-->" + wordsWithoutList(ar, 1));
	}

	public static List wordsWithoutList(String[] words, int len) {
		List<String> a1 = new ArrayList<String>();
		for (int i = 0; i < words.length; i++) {
			if (words[i].length() != len) {
				a1.add(words[i]);
			}
		}
		return a1;
	}

}

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wordsWithoutList value-->[bb, ccc]

i wrote in eclipse with generics which works fine. How to write using Streams just to get fundamental idea?

You could use something like this:

	public static List<String> wordsWithoutList(String[] words, int len) {
                return Arrays.stream(words) // Make a stream that produces the elements of the array.
                        .filter(word -> word.length() != len) // Keep only the words with length different than len.
                        .collect(Collectors.toList()); // Collect the resulting elements in a List.
	}

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You could use the enhanced for-loop to increase readability.  

public List wordsWithoutList(String[] words, int len){
    List<String> list = new ArrayList();
    for(String word: words){
		if(word.length() != len)list.add(word);
    }
    return list;
}

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import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.stream.Collectors;

public class WordsWithoutList {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		String[] ar = { "a", "bb", "b", "ccc" };
		System.out.println("wordsWithoutList value-->" + wordsWithoutList(ar, 1));
	}

	//public static List wordsWithoutList(String[] words, int len) {
	/*
		List<String> a1 = new ArrayList<String>();
		for (int i = 0; i < words.length; i++) {
			if (words[i].length() != len) {
				a1.add(words[i]);
			}
		}
		return a1;*/
		//}
	
	
	public static List<String> wordsWithoutList(String[] words, int len) {
        return Arrays.stream(words) // Make a stream that produces the elements of the array.
                .filter(word -> word.length() != len) // Keep only the words with length different than len.
                .collect(Collectors.toList()); // Collect the resulting elements in a List.
}

}

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above works and passes test as below
wordsWithoutList value-->[bb, ccc]

public List wordsWithoutList(String[] words, int len) {
 List<String> a1 = new ArrayList<String>();
for(int i=0;i<words.length;i++){
   if(words[i].length()!=len){
   a1.add(words[i]);
   }
}
return a1;
}

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above also passes all tests and looks more simple

Just because I like the look you can still loop through the array without incrementing the index (no points please) -
for (word : words) {
      if (words.length() != len) {
      a1.add(word]);
}

sure. same as ID: 41776694 right?

Yes, exactly. Sorry, rrz, I didn't see that post before.