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Title |
Test
Details
command line option no duplicate
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Expression |
\s*((a|b|c)\s+(?!.*\2.*))*(a|b|c)\s*
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Description |
suppose you have a exe/command take options like "a b c" or "b c a", the sequence doesn't matter, but on option should only appear at most once.
The ?! is "negative look ahead", \2 refer the second group.
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Matches |
"b c a", " a c b ", "a b c "
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Non-Matches |
"a b c a", "b c a c", "a b c d", "ab c "
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Author |
Rating:
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Wang , Feng
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