This is a special case of the general problem of program synthesis[1][2][3][4], where the search space of possible programs are all regex strings and the seed driving the synthesis is Input-Output examples.

There's research [5][6] as well as practical tools [7][8][9].

[1] https://en.wikipedia.org/wiki/Program_synthesis

[2] https://www.microsoft.com/en-us/research/project/program-syn...

[3] https://dl.acm.org/doi/10.1145/1836089.1836091

[4] https://royalsocietypublishing.org/doi/10.1098/rsta.2015.040...

[5] https://cs.stanford.edu/~minalee/pdf/gpce2016-alpharegex.pdf

[6] https://www.researchgate.net/publication/261794574_Automatic...

[7] https://regex-generator.olafneumann.org/

[8] http://regex.inginf.units.it/extract/

[9] https://stackoverflow.com/questions/6219790/need-a-regex-too...