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regexstringtestingcorruptiondata-integrity

Search for consecutive sequence violation

I want to test for string corruption and it would be easiest to use a regex that finds violations of a repeated sequence of characters. Suppose the sequence used for validating integrity is 0 to 9.

For example, '0123456790123456789' would match '79' because '8' is missing.

'01234567555890123456789' would match '75558' because '555' doesn't belong. The specific string returned isn't important, just the flagging of at minimum the first location of corruption.

How can I achieve this with a regular expression, if this is even possible with a regex?

Solution

  • You could spell out the sequence like this:

    (0[^1]|1[^2]|2[^3]|3[^4]|4[^5]|5[^6]|6[^7]|7[^8]|8^[9]|9[^0])

    In 01234567555890123456789 it returns two matches 75 and 55 - it will at least reliably find the first broken link.

    I don't think much more can be done in regex alone since regex cannot do a sorted comparison in itself.