如何安全地将逗号分隔的字符串转换为数字数组

Question

Edit :

Why this is not a duplicate

This question specifically addresses the problem that empty strings as well as any number of space characters are converted to 0 using Number(str) .

Take a look at the following snippet:

 convertBtn.addEventListener('click', () => console.log(toArrayOfNumber(foo.value))) const toArrayOfNumber = str => str.split(',').map(Number); 

 <input type="text" id="foo" value="1,2,4,-1" /> <button type="button" id="convertBtn">convert to array of numbers</button> 

As long as the input has a proper value everything works fine. Now I want to make it failsafe for the following values:

• ,
• , ,,

What caught me off guard here is that Number("") and Number(" ") both return 0 (which I don't want as for my usecase I don't want "" or any number of spaces to be considered a Number ).

So I came up with this:

 convertBtn.addEventListener('click', () => console.log(toArrayOfNumber(foo.value))) const toArrayOfNumber = str => str.split(',').filter(x => x.trim() !== "").map(Number); 

 <input type="text" id="foo" value="1,2,4,-1,,, ,, 11" /> <button type="button" id="convertBtn">convert to array of numbers</button> 

This feels awkward, I'm hoping there is an obvious and better solution which I don't see.

Answer 1

Answer from @KendallFrey (who is refusing to post so I'm stealing his solution)

'1,2,4,-1,,, ,, 11,0,0'.split(/[, ]+/).map(x=>+x)

You can still use .map(Number) but x=>+x is 1 byte shorter.

Results in the console: (7) [1, 2, 4, -1, 11, 0, 0]

Another regex solution (that doesn't allow decimals): /-?\\d+/g

Answer 2

If you're only dealing with integers the following will also work. 0's will be kept but empty values will be removed.

split(',').filter(num => !isNaN(parseInt(num))).map(Number);

Example

 const str = '1,2,4,-1,,, ,0, 11'; console.log(str.split(',').filter(num => !isNaN(parseInt(num))).map(Number)); 

Answer 3

Try this:

 const value="-99,1,2,4,-1,,, ,0,, 11" const toArrayOfNumber = str => str.split(',').map(num => num.trim() && Number(num)).filter(num => !Number.isNaN(num) && typeof num != 'string'); const nums = toArrayOfNumber(value); nums.forEach(num => console.log(typeof num, num)); 

We use the results of trim to determine if we should process it like a number. If not then we just have a string and that is filtered out.

Answer 4

You could also do this via Array.reduce where in each iteration you check with isNaN for the parseInt :

 let data = "1,2,4,-1,,, ,0, 11" let r = data.split(',').reduce((r,c) => isNaN(parseInt(c)) ? r : [...r, +c],[]) console.log(r) 

This way you only iterate over the array once post splitting. Also this would keep zeros intact and just drop any non numbers.