How to count array elements inside an array in javascript?

Question

I have an array as follows in nodejs

 var dataary=[];
    dataary=[ [ 'reg_no', 'slno', 'name', 'email', 'rollno' ],
    [ 'int', 'int', 'varchar', 'varchar', 'int' ],
    [ '100', '11', '255', '255', '100' ] ]

I need the count of array elements.As i do dataary.length it will return 3. But i need the count as 5 (count of elements inside array).How can i get the count of elements. ?

Welcome to Stack Overflow! Please take the tour and read through the help center, in particular How do I ask a good question? Do your research, search for related topics on SO, and give it a go. If you get stuck and can't get unstuck after doing more research and searching, post a minimal reproducible example of your attempt and say specifically where you're stuck. People will be glad to help. Good luck! — T.J. Crowder
– T.J. Crowder, Commented Dec 19, 2017 at 11:13
Note: It just so happens that the length is 5 for all of the arrays in dataary, but it could just as easily be that they each had different lengths. — T.J. Crowder
– T.J. Crowder, Commented Dec 19, 2017 at 11:14
But i need the count of elements inside each array - loop through the main array and extract the length of each sub array? - stackoverflow.com/questions/12502843/… — Nope
– Nope, Commented Dec 19, 2017 at 11:17
But i need the count as 5 You need to get answer as 5 or 15? — Shalitha Suranga
– Shalitha Suranga, Commented Dec 19, 2017 at 11:17

David Vicente · Accepted Answer · 2017-12-19 11:17:46Z

3

With map you can get all lengths in one array and then you can sum them or do whatever you want to do.

var allLengths = dataary.map(element => {
   return element.length;
});

answered Dec 19, 2017 at 11:17

David Vicente

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Comments

Manikant Gautam · Accepted Answer · 2017-12-19 11:22:37Z

0

Iterate through loop and get length of each individual array .The forEach() method executes a provided function once for each array element.

var dataary=[];
    dataary=[ [ 'reg_no', 'slno', 'name', 'email', 'rollno' ],
    [ 'int', 'int', 'varchar', 'varchar', 'int' ],
    [ '100', '11', '255', '255', '100' ] ,
    [ '1', '2', '3' ]]
    dataary.forEach(function(element) {
    console.log(element.length);
    });

answered Dec 19, 2017 at 11:22

Manikant Gautam

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Comments

oae · Accepted Answer · 2021-01-03 20:47:39Z

0

I would do it that way...

dataary.reduce((count, innerArray) => count + innerArray.length, 0);

answered Jan 3, 2021 at 20:47

oae

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