#1
  1. Contributing User
    Devshed Frequenter (2500 - 2999 posts)

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    Near trivial optional group


    I'm having a brain freeze or something. I can't figure out how to do a trivial group.

    grep "<us-references-cited>" ipg130122.xml

    results in lots of lines, like:

    <us-references-cited>
    <us-references-cited>

    but
    grep "<(us-)references-cited>" ipg130122.xml

    can't find any. Clearly this an operator error. Thanks
  2. #2
  3. Transforming Moderator
    Devshed Supreme Being (6500+ posts)

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    In regular non-GNU grep, ( ) are actually literal characters and \( \) will group.
  4. #3
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    Devshed Frequenter (2500 - 2999 posts)

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    Ah, ok, now do you know how python interprets the parens? Does it want them quoted, or unquoted?
  6. #4
  7. Transforming Moderator
    Devshed Supreme Being (6500+ posts)

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    That \( is pretty unusual - it's normally the complete opposite behavior.

    The re docs say that ( ) is the correct form: no backslashes.

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