如何检测数组是否具有年份值并定义它？

Question

Here is example array:

[ 'test', '1994', 'test', 'test', '2018']

What I need is 2 arrays out of example array:

[ 'test', 'test', 'test' ]

and

[ '1994', '2018' ]

I tried to use indexOf but seams I can't pass array with all possiable years value (~1900-present/2018)

I figure out what switch statment will work but it's gonna be a lot of copy pasted code, I believe there is better way to do it.

Edit:

Some of you didn't understand what I wanted to get year value not just a number , so answer with regex is most closed to what I wanted, i just replace regex after googling to ^(19|20)\\d{2}$ . So year could be only 1900-2099.

Answer 1

You could take a check isNaN and push the value to either number ot text array.

 var array = ['test', '1994', 'test', 'test', '2018'], text = [], numbers = []; array.forEach(s => [numbers, text][+/^(19|20)\\d{2}$/.test(s)].push(s)); console.log(text); console.log(numbers); 

Answer 2

You can reduce the array to 2 separate arrays. Check if the string can be casted to a number between the range of 1900-2018, and if it evaluates to:

1. false - casted to 0, and pushed to the 1st sub-array
2. true - casted to 1, and pushed to the 2nd sub-array

Then you can get the two arrays using array destructuring.

 const arr = ['test', '1994', 'test', 'test', '2018']; const isYear = (n) => n >= 1900 && n <= 2018; const [test, years] = arr.reduce((r, s) => { r[+isYear(+s)].push(s); return r; }, [[], []]); console.log(test); console.log(years); 

Answer 3

You can use the function reduce to group the strings according to their contents.

 let arr = [ 'test', '1994', 'test', 'test', '2018'], isYear = (s) => !isNaN(Number(s.trim())), result = arr.reduce((a, s) => { if (isYear(s)) a.years.push(s); else a.strings.push(s); return a; } , {years: [], strings: []}); console.log(result); 

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Answer 4

You can use regex to do this:

var arr = [ 'test', '1994', 'test', 'test', '2018'];
var dates = [];
var nonDates = [];
for (var i = 0; i < arr.length; i++) {
    if (arr[i].match(/^\d{4}$/))
        dates.push(arr[i]);
    else
        nonDates.push(arr[i]);
}

Answer 5

You can also use filter along with the isNaN check to accomplish this.

 var array = ['test', '1994', 'test', 'test', '2018']; var text = array.filter(e => isNaN(e)), years = array.filter(e => !isNaN(e)); console.log(text); console.log(years);