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phpregexpreg-matchstripos

string contains 5 numbers and line

I am looping trough a txt file which contains lines for example:

asdasdasd
lorem ipsum
lorem 12345-1
more lorem ipsum bacon

From this I need to know when the line founds text 12345-1

Lorem in the beging is inrelative.

Can I use stripos like

if (stripos('/^[1-9]{0,5}$-1/', $line) !== false)

I dont know the right regex. Of course the 12345 can be what ever, but its always 5 digits and ends with -1

Solution

  • To find a 5-digit chunk followed with -1, you may use

    /\b[0-9]{5}-1\b/

    Or, if word boundaries (\b) is too restrictive, use lookarounds:

    /(?<!\d)\d{5}-1(?!\d)/

    See the regex demo

    Use it with preg_match:

    if (preg_match('/\b[0-9]{5}-1\b/', $line))
{
     echo "Found!";
}

    Pattern details:

    • \b - a leading word boundary (or (?<!\d) - a negative lookbehind making the regex fail if there is a digit before the current location)
    • [0-9]{5} - 5 digits
    • -1 - a literal char sequence -1
    • \b - a trailing word boundary (or (?!\d) - a negative lookahead making the regex fail if there is a digit right after the current location)