I want to delete an element that in this case is an array within another array
arr = [['a','b'],['c','d'],['e','f']];
tag = ['c','d'];
I want to remove tag from arr, and for that I'm trying to do this:
arr.splice(arr.indexOf(tag), 1);
But I do not know why it does not work, How could I do this?
It doesn't work because [1, 2, 3] != [1, 2, 3] in javascript. Arrays and object comparisons are not done by the values. This also applies to indexOf().
You need to tell javascript what you mean by equality:
arr = [['a','b'],['c','d'],['e','f']];
tag = ['c','d'];
function array_equals(a, b){
return a.length === b.length && a.every((item,idx) => item === b[idx])
}
console.log(arr.filter(item => !array_equals(item, tag)))
You need to check every item in the arrays, because with Array#includes, you check the object reference, which is not the same, even with same values.
Assuming the same length of the arrays for checking.
var arr = [['a', 'b'], ['c', 'd'], ['e', 'f']],
tag = ['c','d'],
result = arr.filter(a => !a.every((v, i) => v === tag[i]));
console.log(result);
['c', 'd'] when tag = ['c','d', 'e']You will need to use a doble filter. First to separate the arrays and second will be the one comparing each value and will filter out the tag element.
arr = [['a','b'],['c','d'],['e','f']];
tag = ['c','d'];
console.log(arr.filter(el=> el.filter((c,i)=> c != tag[i]).length != 0))In a lazyer alternative, the arrays can be converted and compared as strings if none of the values contains , :
var arr = [['a', 'b'], ['c', 'd'], ['e', 'f']], tag = ['c', 'd'];
console.log( arr.filter(a => a != tag + '') )Here is a filter function which removes number 5 from an array of number arrays:
let winComb = [
[1, 2, 3],
[4, 5, 6],
[7, 8, 9],
[1, 4, 7],
[2, 5, 8],
[3, 6, 9],
[1, 5, 9],
[3, 5, 7],
];
for (let i = 0; i < winComb.length; i++) {
for (let j = 0; j < 3; j++) {
newArr = winComb[i].filter(function (item) {
return item !== 5;
});
}
console.log(newArr);
}
indexOfcan't findtag. Don't think you can use an array as an argument for it.indexOfuses strict equality. Different arrays are not strictly equal because they're different objects, even if they contain the same elements. You'd need to use a filter and either manually or via a library do an array compare (and decide other things like if order is important etc).['c','e']it will fail and remove the second element