CODEWITHSUNDEEP
javastringfor-loopif-statementarraylist
gnrcs
gnrcs

Reputation: 89

How to check if an item in an ArrayList<String> does not contain a certain word?

I want to use a for loop like this: 

`button.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
    Object.setList();

for(int i = 0; i < Object.getList.size(); i++)
    if(!Object.getList.get(i).trim().toLowerCase().contains("hello")) {
        Toast.makeText(getContext(), "List does not contain "Hello", Toast.LENGTH_LONG).show;
    }
}`

This is my model:

public class Object {
    private ArrayList<String> mArrayList;

    public void setList() {
        mArrayList = new Arraylist<>();
        mArrayList.add("Random Message");
        mArrayList.add("ZZZZ")
    }

    public ArrayList<String> getList() {
        return mArrayList;
    }
}

I still keep getting the Toast message, but it works just fine when i use:

if(!Object.getList().toString.trim().toLowerCase().contains("hello"))

Upvotes: 1

Views: 2943

Answers (3)

raviiii1
raviiii1

Reputation: 976

If your aim is to check if each string in the list does not have "hello" and show toast each time then you can do so :

Object.getList().forEach(el -> {
if(!el.toLowerCase().contains("hello")){
  // show toast
}
})

If your aim is to check if each string in the list does not have "hello" and show toast only once the do so :

if(Object.getList().stream().noneMatch(el -> !el.toLowerCase().contains("hello"))){
// toast
}

If you wanna simply check if there is any sting that matches any element of list then do what @SatyendraKumar sugested.

Upvotes: 0

Satyendra Kumar
Satyendra Kumar

Reputation: 367

If you want to do it one line, do it like this:

if(object.getList().stream().noneMatch(it -> "hello".equalsIgnoreCase(it))){
  // ...
}

This will work if you are using Java 8.

Upvotes: 1

Prashant
Prashant

Reputation: 5393

I am not really sure how this expression:

Object.getList().toString.trim().toLowerCase().contains("hello")

works. Consider two adjacent elements: "he" and "llo". Even in this case your solution would state that the string "hello" exists in the ArrayList. Since there is ho hashing in ArrayList, the only solution is via brute force (Giving a performance of O(n)). Here is the solution:

for(String element: list) {
   if (str.equalsIgnoreCase(element)) {
       // Found
   }
}

Upvotes: 1

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