I have some arrays as below and I want to know how to get the index of the first number by js?
Arr1=[null,null,null,null,null,...,343,959,543,..,252,null,null,...,null]
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1How do I ask and answer homework questions?Andreas– Andreas2022-08-20 15:20:05 +00:00Commented Aug 20, 2022 at 15:20
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@Andreas, the question is how to find an index, not a value in the array. The provided "answered topic" shows how to find a value. This might be a duplicate of existing question, but definitely not the one provided as duplicate of.vanowm– vanowm2022-08-20 15:26:18 +00:00Commented Aug 20, 2022 at 15:26
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2 Answers
You can use findIndex:
Arr1.findIndex(value => value !== null)
1 Comment
Andreas
That's an obvious duplicate (and a question without any effort, and - imho - most likely homework). So why the answer instead of a close-vote as dupe?
You can loop through the array and check it's value:
const Arr1=[null,null,null,null,null,343,959,543,252,null,null,null];
let index = -1;
for(let i = 0; i < Arr1.length; i++)
{
if (Arr1[i] !== null)
{
index = i;
break;
}
}
console.log(index);