JS create new array from certain item-CodePudding

I have 2 dimensional array myArray:

[
  [ '567576', 'John', 'Doe' ],
  [ '098897', 'John', 'Doe' ],
  [ '543539', 'John', 'Doe' ],
  [ '234235', 'John', 'Doe' ],
  [ '345348', 'John', 'Doe' ],
  [ '432574', 'John', 'Doe' ]
]

Is it possible to create a new array from myArray starting from a certain first value? For example create a new array starting from id 543539. Anything above the array containing 543539 will not be added.

CodePudding user response：

You can make use of findIndex() which returns the index of the first item that matches the condition. Combine it with slice() to cut your array at the specific position:

const myArray = [
  ['567576', 'John', 'Doe'],
  ['098897', 'John', 'Doe'],
  ['543539', 'John', 'Doe'],
  ['234235', 'John', 'Doe'],
  ['345348', 'John', 'Doe'],
  ['432574', 'John', 'Doe']
]

console.log(myArray.slice(myArray.findIndex(item => item[0] === "543539")));

CodePudding user response：

const arr=[
  [ '567576', 'John', 'Doe' ],
  [ '098897', 'John', 'Doe' ],
  [ '543539', 'John', 'Doe' ],
  [ '234235', 'John', 'Doe' ],
  [ '345348', 'John', 'Doe' ],
  [ '432574', 'John', 'Doe' ]
];

const res=arr.slice(arr.findIndex(a=>a[0]=='543539'));

console.log(res);

CodePudding user response：

Sure, assuming all the internal arrays are structured the same way, you can do something like let newArray = myArray.filter(innerArray => Number(innerArray[0]) > 543539)

Edit: This is assuming you want all subarrays where the first item is a number larger than 54539, as opposed to finding all of the subarrays that physically follow the first occurrence of a subarray with 54539 as the first value

CodePudding user response：

Yes, that is possible and straightforward process. You can use the javascript map method which returns a new array

newArray = myArray.map(item=> item[0])