CODEWITHSUNDEEP
java
shiva
shiva

Reputation: 159

How can I compare String value with ArrayList of String type in Java?

My requirement is comparing String to ArrayList which contains a list of strings. Can any one suggest me?

Upvotes: 14

Views: 139692

Answers (7)

Saidurga Padala
Saidurga Padala

Reputation: 1

Convert your Array to Array list first

List al = Arrays.asList("Your Array");

Then compare using contains or equals

if (al.contains("Your String") {
    // Code
}

Upvotes: 0

Java_Waldi
Java_Waldi

Reputation: 934

This is your method:

   private boolean containsString(String testString, ArrayList<String> list) 
   {
        return list.contains(testString);
   }

Upvotes: 8

user831722
user831722

Reputation:

ArrayList can contain one or more Strings. You cannot compare String with ArrayList. But you can check whether the ArrayList contains that String ot not using contains() method

String str = //the string which you want to compare
ArrayList myArray =// my array list
boolean isStringExists = myArray.contains(str);// returns true if the array list contains string value as specified by user

Upvotes: 4

Tapas Bose
Tapas Bose

Reputation: 29806

If you are willing to use Lambdaj, then check the presence of the String as:

private boolean isContains(ArrayList<String> listOfStrings, String testString) {
    return (Lambda.select(listOfStrings, Matchers.equalTo(testString)).size() != 0);  
}

Using static import of select and equalTo increase the readability:

select(listOfStrings, equalTo(testString));

Upvotes: 3

Snicolas
Snicolas

Reputation: 38168

There are different options you could consider :

  • a simple for each loop using equals on each member of your list to compare it to string A.
  • sorting all strings in list in order to boost up comparison and find if a string in the list matches A.
  • using a sortedSet to achieve the above
  • putting alls string in the intern string pool using intern method on every item in the list and on string A. This will allow to compare strings using == and not equal anymore. Comparison would then be much faster.
  • using a hashmap to achieve better comparison speeds
  • an identity hashmap to mix the two preceding strategies.

Well, the are pros and cons to those methods, it all depends on what you want to do and why and how you compare strings.

Regards, Stéphane

Upvotes: 4

Logan
Logan

Reputation: 2505

Use 

ArrayList.contains("StringToBeChecked");

If the String is present in the ArrayList, this function will return true, else will return false.

Upvotes: 22

Bohemian
Bohemian

Reputation: 424983

Look at the List#contains(T obj) method, like this:

List<String> list = new ArrayList<String>();
list.add("abc");
list.add("xyz");
list.contains("abc"); // true
list.contains("foo"); // false

Upvotes: 8

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