Removing multiple array values with Array.filter()

Question

I have an array of strings:

let arr = ["1", ":", "3", "0", " ", "P", "M"];

I want to remove the ":" and the whitespace using one filter helper. Is this possible? It works if I chain the methods together.

arr = arr.filter(n => n !== ":").filter(n => n !== " ");

Is there a way that I could run this inside of only one filter method without chaining it? I realize I could also get this done with map() and run a conditional for string comparisons, but I was curious if it could be done with filter().

How about arr.filter(n => n !== ":" && n !== " ")?

gnud
– gnud

2018-04-09 22:47:03 +00:00
Commented Apr 9, 2018 at 22:47 — gnud
– gnud, Commented Apr 9, 2018 at 22:47

Jorge Fuentes González · Accepted Answer · 2018-04-09 22:47:34Z

4

Chain the conditionals with an AND operator, like this:

arr.filter(n => n !== ":" && n !== " ");

answered Apr 9, 2018 at 22:47

Jorge Fuentes González

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1 Comment

newman Over a year ago

Wow, I feel very silly for not thinking to try that. Thank you!

Ele · Accepted Answer · 2018-04-09 23:07:31Z

2

You approach only needs to join the conditions using AND logical operator

arr.filter(n => n !== ":" && n !== " ");
                          ^^

This approach uses the function test as a handler for the function filter

This is the regex: [:\s]

let arr = ["1", ":", "3", "0", " ", "P", "M"],
    result = arr.filter(s => !/[:\s]/.test(s));
    
console.log(result);

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As academy approach you can join replace and split

Regexp: /[:\s]/g

Assuming the other elements don't have spaces nor colons

let arr = ["1", ":", "3", "0", " ", "P", "M"],
    result = arr.join('').replace(/[:\s]/g, '').split('');
    
console.log(result);

.as-console-wrapper { max-height: 100% !important; top: 0; }

edited Apr 9, 2018 at 23:07

answered Apr 9, 2018 at 22:55

Ele

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Comments

Jason · Accepted Answer · 2018-04-09 22:51:24Z

1

Use a regular expression

arr.filter(n => !n.match(/[:\s]/) );

it will match any of the values inside [ and ]

edited Apr 9, 2018 at 22:51

answered Apr 9, 2018 at 22:49

Jason

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1 Comment

Ele Over a year ago

Using the function match is ugly!

Ele · Accepted Answer · 2018-04-09 23:10:08Z

1

I will rather do it by making blacklist array

let arr = ["1", ":", "3", "0", " ", "P", "M"],
    notAllowed = [' ', ':'];
    
console.log(arr.filter(a => !notAllowed.includes(a)));

edited Apr 9, 2018 at 23:10

Ele

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answered Apr 9, 2018 at 22:50

sumit

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3 Comments

sumit Over a year ago

really, can you please explain a bit?

sumit Over a year ago

Thanks ele, I changed my answer. Thanks for sharing this thing, I never knew this before. This is the second time I learnt something from you :)

Ele Over a year ago

Interesting approach! :)

see sharper · Accepted Answer · 2018-04-09 22:48:25Z

0

arr = arr.filter(n => n !== ":" && n !== " ");

Pretty simple really! :)

answered Apr 9, 2018 at 22:48

see sharper

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