Conditional .length of a list

Question

I have a list with the following values:

const myList = [True, False, False]

With myList.length I get the value 3.

Now I want the length of the list with all False values.

How can I return the length with a condition?

You can `filter` it first then invoke `length` – flyingfox Nov 23 '22 at 09:46 — flyingfox, Nov 23 '22 at 09:46
please add the values of `True` and `False`. – Nina Scholz Nov 23 '22 at 09:47 — Nina Scholz, Nov 23 '22 at 09:47

score 3 · Accepted Answer · answered Nov 23 '22 at 09:48

3

const myList = [True, False, False].filter(el => el === false)
console.log(myList.length)

answered Nov 23 '22 at 09:48

voidbrain

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flyingfox · Answer 2 · 2022-11-23T09:54:18.810

1

You can use Array.filter() to do it

let len = myList.filter(i => !i).length

const myList1 = [true, false, false]
let len1 = myList1.filter(i => !i).length
console.log(len1)

const myList2 = ['True', 'False', 'False']
let len2 = myList2.map(i => i.toLowerCase() === 'true').filter(i => !i).length
console.log(len2)

edited Nov 23 '22 at 09:54

answered Nov 23 '22 at 09:47

flyingfox

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score 1 · Answer 3 · answered Nov 23 '22 at 09:49

1

You could count the values.

const
    True = true,
    False = false,
    getCount = (array, value) => array.reduce((t, v) => t + (v === value), 0),
    myList = [True, False, False];

console.log(getCount(myList, False));

answered Nov 23 '22 at 09:49

Nina Scholz

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Conditional .length of a list

3 Answers3