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I like it! Here is a gotcha my students stumble on. I have not noticed it while skimming your book: ^ and $ do not have special priorities. To match alternative
by mci 5y ago
I like it! Here is a gotcha my students stumble on. I have not noticed it while skimming your book: ^ and $ do not have special priorities. To match alternatives, write ^(abc|def)$, not ^abc|def$
- asicsp 5y agoYeah, that's a good case to be aware of. I do mention it in the book while discussing anchors (indicating alternatives have their own independent anchors) [0] and grouping [1]. I also discuss how `re.fullmatch` is useful, especially when constructing an alternation pattern from a list of terms. Easier to use fullmatch instead of manually adding a group and string anchors. [0] https://learnbyexample.github.io/py_regular_expressions/alternation-and-grouping.html#alternation https://learnbyexample.github.io/py_regular_expressions/alte... [1] https://learnbyexample.github.io/py_regular_expressions/alternation-and-grouping.html#grouping https://learnbyexample.github.io/py_regular_expressions/alte...
- staticautomatic 5y agoWithout the group, does this match abc at the start or def at the end?
- schoen 5y agoYes, exactly.