Question 241192 in Javascript Question posted in
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Javascript – Regex to find if string contains numbers and (commas, dots or -)

I’m attempting to create a valid regular expression to detect if a string is only numbers and digits or if it contains letters.

The expression I’m using is:

/^d+.?d+$|^d+$/.test(masked)

TypeScript demo

However whenever I type the next (.) index, the expression turns false:

const masked = '123.422' -> TRUE
const masked = '123.422.' -> FALSE (SUPPOSE TO BER TRUE)

What I want to achieve is:

const masked = '123.422.433-43' -> TRUE
const masked = 'Hello' -> False
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2

Answers


  1. 0

    Try

    [^a-zA-Z]+

    It will match if there are no letters

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  2. 0

    Your description is insufficient, but I’ll try to give it a try anyway since I enjoy creating regex.

    from your description, I assume you know very little about regex, and if you need some help how to use it, you should take a look at this online tool called Regexr

    The Regex you are using, (that I simplified removing the beginning and end characters) d+.?d+|d+. only accepts these formats:

    DIGIT(S) + DIGIT(S) ( left side expr when dot is missing)
    DIGIT(S) + DOT + DIGIT(S) ( left side expr with dot )
    DIGIT(S) + DOT

    this means it fails on a simple case, with the current format, you can’t have a single digit.

    This is my suggestion:

    .?(d(.)?)+

    The expression might start with a dot, followed by a sequence of Digits and dots.
    This allows numbers like 123, .123, 123.123 or .123..123.
    You can’t have more than one consecutive dots. or just a single dot.

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