Extract blood pressure values from string-CodePudding

I have some strings containing blood pressure data, the numbers before the / indicate the higher/upper end of the blood pressure (systolic), and the numbers after the / indicate the lower end of the blood pressure (diastolic).

The strings are like this

let str1 = "170/80"; // Should Pass
let str2 = "90/60"; // Should Pass
let str3 = "140/90"; // Should Pass
let str4 = "should not/pass"; // Shouldn't Pass

I have a regex that tries to make sure that these strings indeed are blood pressure readings, i.e., making sure that the values are all numbers and in between them is a / but it doesn't seem to work (It's not matching even with the supposedly correct strings).

My regex is: ((\d)/(\d))

Can anyone tell me why it's not working? and what should be the correct regex for this?

CodePudding user response：

As mentioned in the comments, you can use \d to match multiple digits. However, if your text can contain other numbers, you might want to use the more specific \d{1,3} to capture only values in the valid range for blood pressure. The complete regex would be ((\d{1,3})\/(\d{1,3}))

CodePudding user response：

The issue in your regex is that you're not escaping your slash \, but also you are matching single digits \d. In order to solve these problems, you may want a regex like this:

(\d )\/(\d )

Check the demo here.

CodePudding user response：

Escape the slash and use more than one digit

https://regex101.com/r/uC2w4h/1

Here with sanity tests to remove dates or other weird numbers. Change 45 to however low you want to test.

const str = `170/80  90/60 140/90 should not/pass on 11/12`
const bps = [...str.match(/(\d{2,3})\/(\d{2,3})/g)].filter(match => {
  const [syst,diast] = match.split("/")
  return  syst > 45 && diast > 45;
})

console.log(bps)