Regular expressions help

JavaScript
1

Hi Guys,

I just had a quick question and wanted to know if anybody could help with a regular expression question. I am currently completing the Metric-Imperial Converter from the Information Security and Quality Assurance Projects and am looking to find the regular expression that will make sure the input string is a section of digits or a fraction and then only characters at the back. I am then splitting the string and taking the number and characters to determine the quantity and unit that needs to be converted

for example-

I’m using this to separate the digits

var reg = /[a-z,A-Z]/g;
var result = input.split(reg);

result= result[0]

these inputs will pass 2344343kg, 3443lb etc but the problem is if I have a group of characters in the middle like 455ht45lb or 5uuuu43m then it will be the wrong format. I guess I also have the same problem when I try to get the unit and it is not purely characters.

So what I want to do is run it through a check to make sure it is the correct format before splitting it. Would anyone have any ideas on this???

2

Your regex is basically splitting every character? I don’t see how it is matching any number at all.

By your specifications, may this regex work for you?

/^[\d\.,]+[a-z]{1,2}$/

If not please provide the link to the challenge and I’ll re-read your post and try to understand it better.

3

What do you want to do with like 455ht45lb or 5uuuu43m? Discard them? Split them?

Are there limitations on the number of chars in a unit of measure?

5

Discard the start (which is to be the quantity, but is invalid) but keep the end(meant to be the unit)

eg (discard(455ht45) and keep(lb)) or discard(5uuuu43) keep(m).

[‘gal’,‘l’,‘lb’,‘kg’,‘mi’,‘km’] These are the only units of measurement. So between 1-3 Characters.

6

Im using two different regular expressions.

This one to get the first input. Which will be the quantity-

var reg = /[a-z,A-Z]/g;
var result = input.split(reg);

result= result[0]

And this one to get the unit of measurement-

   var regUnit=/[0-9]/g;
    
    var result=input.split(regUnit)
    result =result[result.length -1].toLowerCase();

The actual lesson can be found here-

https://learn.freecodecamp.org/information-security-and-quality-assurance/information-security-and-quality-assurance-projects/metric-imperial-converter

7

OK then maybe try this.

var result = input.match(/\d+\.{0,1}\d*(?=(gal|l|lb|kg|mi|km)$)|(gal|l|lb|kg|mi|km)$/ig)

An input of “mi” would also pass though.