How to check if a specific index of an array contain a value java

Question

say I had an array (Hello,1,2,HI,1,2)

How would I check if index 1 was = to 'Hello' is a very simple question, but cannot find an answer.

This is what I have tried,it is inside a for loop, my array is of type string:

  if(array[i] == "Hello" ){
  // do something 
  }

Reopened: this is not (necessarily) simply about comparing strings, but comparing an element of an array of objects to a string. (But will not lose sleep if re-closed). — Bathsheba, Dec 15 '16 at 14:04
@Bathsheba : the question is not precise enough to know that it is not an array of strings. Maybe it should be edited to add details about that. — Arnaud, Dec 15 '16 at 14:08
They just have and it rather ruins my answer. Such is life ;-( — Bathsheba, Dec 15 '16 at 14:08

score 2 · Answer 1 · answered Dec 15 '16 at 14:02

2

if ("Hello".equals(array[i])){
    // do something
}

is, in many ways, the best way.

This will work

If array[i] is null.
If array[i] is a type other than a java.lang.String

I appreciate that you're a beginner and these yoda expressions are not to everyone's taste, but I couldn't resist.

(Note that a single = is an assignment rather than a test for equality, and == compares references rather than contents for non-primitive types in Java.)

answered Dec 15 '16 at 14:02

Bathsheba

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Should specify that `i` is just the index, and in his/her case: "check if index 1 was = to 'Hello'", `i` would be just 0 or 1 depending on their understanding of index – Honinbo Shusaku Dec 15 '16 at 14:10
So you re-opened this question to answer what the dupe already said? – Tom Dec 15 '16 at 14:12
Prior to the edit the question was notably different (and I had already answered: I, along with many folk, consider it poor form to gold hammer reopen in order to answer). It ain't now though. – Bathsheba Dec 15 '16 at 14:14
It was an assignment, instead of a comparison, but OP said that he likes to compare the array item with the literal :P. Oh and yes, you answered, before reopening. That was a misunderstanding on my part. *"I, along with many folk, consider it poor form to gold hammer reopen in order to answer"* Good to hear (in case the question really is a dupe; if closing was wrong, then opening and answering would be fine imo). – Tom Dec 15 '16 at 14:19

score 0 · Answer 2 · answered Dec 15 '16 at 14:02

0

it depends on your array type. in your case it is String, so

if(array[i].equals("Hello") {
 // do something
}

answered Dec 15 '16 at 14:02

javanoob

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This will throw an NPE if `array[i]` is `null`. – Bathsheba Dec 15 '16 at 14:09
@javanoob If for example I wanted to check whether index 1 was an integer would this be possible or not, because the array is of type string – j1234567 Dec 15 '16 at 14:09
yes ; Integer.parseInt(array[i]) can parse an integer and will throw exception otherwise – javanoob Dec 15 '16 at 14:27
@Bathsheba, yes but your answer already covers that – javanoob Dec 15 '16 at 14:29

How to check if a specific index of an array contain a value java

2 Answers2