Finding an element in an array in Java

Question

Does Java have a built-function to allow me to linearly search for an element in an array or do I have to just use a for loop

User · Accepted Answer

There is a contains method for lists  so you should be able to do   Arrays asList yourArray  contains yourObject     Warning  this might not do what you  or I  expect  see Tom s comment below

User · Answer

Use a for loop   There s nothing built into array   Or switch to a java util Collection class

User · Answer

You might want to consider using a Collection implementation instead of a flat array   The Collection interface defines a contains Object o  method  which returns true false   ArrayList implementation defines an indexOf Object o   which gives an index  but that method is not on all collection implementations   Both these methods require proper implementations of the equals   method  and you probably want a properly implemented hashCode   method just in case you are using a hash based Collection  e g  HashSet

User · Answer

You can use one of the many Arrays binarySearch   methods   Keep in mind that the array must be sorted first

User · Answer

With Java 8  you can do this   int   haystack    1  2  3   int needle   3   boolean found   Arrays stream haystack  anyMatch x - gt  x    needle     You d need to do   boolean found   Arrays stream haystack  anyMatch x - gt  needle equals x      if you re working with objects

[java] Finding an element in an array in Java

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