Remove a specific item from a 2d array without .filter()

Question

Say I have an 2 dimensional array like this:
array = [
[1,2,3,4,5,true],
[2,3,4,5,6,false],
[3,4,5,6,7,true],
[4,5,6,7,8,false]
]
where true = is the last number a prime
How do I remove all 'false' elements like this
For(let i in array)
If(array[i][5]) //remove array[i][4]

The .filter could be used here, but I am using a library that also hasa filter function inside it, so it won't let me use it. Is there a way to maybe array.splice(i[4], 1); but in another way because this one also didn't work
Weird enough removing the whole subarray didn't work out for me too ( array.splice(i,1); )

Answer 1

you have the wrong syntax)
it will be right:
array[i].splice(4,1);

Answer 2

I'm so dumb😂😅 thanks anyways