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Regex how to match an optional character
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Use
[A-Z]?
to make the letter optional. {1} is redundant. (Of course you could also write [A-Z]{0,1} which would mean the same, but that's what the ? is there for.)
You could improve your regex to
^([0-9]{5})+\s+([A-Z]?)\s+([A-Z])([0-9]{3})([0-9]{3})([A-Z]{3})([A-...
How to check if a process id (PID) exists
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10 Answers
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How do I calculate the normal vector of a line segment?
Suppose I have a line segment going from (x1,y1) to (x2,y2). How do I calculate the normal vector perpendicular to the line?
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Changing every value in a hash in Ruby
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11 Answers
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Rails: Why does find(id) raise an exception in rails? [duplicate]
If there is no user with an id of 1 in the database, trying User.find(1) will raise an exception.
2 Answers
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Ruby Regexp group matching, assign variables on 1 line
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201
You don't want scan for this, as it makes little sense. You can use String#match which will retu...
Gradle, “sourceCompatibility” vs “targetCompatibility”?
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81
targetCompatibility and sourceCompatibility maps to -target release and -source release in javac...
How do you create nested dict in Python?
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313
A nested dict is a dictionary within a dictionary. A very simple thing.
>>> d = {}
&g...
Why is it impossible to build a compiler that can determine if a C++ function will change the value
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13 Answers
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