Trying to get last digit from a string in javascript.
Note that I am not looking to get the last character on a string, but the last digit as a number
For example:
lastDigit("MA01A"); // returns 1
lastDigit("MA01"); // returns 1
lastDigit("1"); // returns 1
lastDigit("1MABC"); // returns 1
lastDigit("MABC"); // returns undefined
How can I get it?
Supposing you may have non-numerical characters at the end of the string, you can traverse the string in reverse and return the first number you encounter, or (e.g.) null otherwise
function getLatestDigit(text) {
for (var i = text.length - 1; i >= 0; i--) {
if (!isNaN(text.charAt(i))) return text.charAt(i);
}
return null;
}
console.log(getLatestDigit("MA01"));
console.log(getLatestDigit("MA12aaaaa"));
console.log(getLatestDigit("NoNumbersHere"));
Here's a version of this that doesn't use a for loop. Two versions: a short one, returning a string, and a slightly longer one returning a number, in case you need that too.
function lastDigit(str) {
// Remove all non-digits from the string and return the last
// character
return str.replace(/[^\d]*/g, '').slice(-1) || undefined;
}
function lastDigitAsNumber(str) {
// Remove all non-digits from the string
const digit = str.replace(/[^\d]*/g, '').slice(-1)
// Parse the last digit as number (this will be 0 for ''
const number = Number(digit)
// Return accordingly
return digit.length > 0 ? number : undefined;
}
console.log(lastDigit("MA01A")); // returns '1'
console.log(lastDigit("MA01")); // returns '1'
console.log(lastDigit("1")); // returns '1'
console.log(lastDigit("1MABC")); // returns '1'
console.log(lastDigit("MABC")); // returns undefined
console.log(lastDigitAsNumber("MA01A")); // returns 1
console.log(lastDigitAsNumber("MA01")); // returns 1
console.log(lastDigitAsNumber("1")); // returns 1
console.log(lastDigitAsNumber("1MABC")); // returns 1
console.log(lastDigitAsNumber("MABC")); // returns undefinedTry this....
var source="MA01";
var lastNum = source.replace(/.*?(\d+)[^\d]*$/,'$1')
alert(lastNum);
var source = "MA01",
lastNum = source.match(/(\d+)(?!.*\d)/)[0];
alert(lastNum);
1 but only because it parses 01, what if the input ended 12?01.
const source="MA01"; let char = source[source.length-1]; console.log(char);