I am trying to figure out how to can condense the number of pattern matching rules I need to create to pick up on conditions like I saw a man at the SW corner of Pike street. For “SW Corner”, I don’t want to write a match rule for every directional variation (N, S, E, W, etc.). I tried to do it with the below, but it isn’t right. Well, it works but it also picks up other things.
Example:
JavaScript
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matcher.add("DIRECTION", None,2
[{}, {"TEXT":{"REGEX":"(?:N)|(?:S)|(?:E)|(?:W)|(?:NW)|(?:NE)|(?:SW)|(?:SE)"}}, {"LOWER":"corner"}]3
)4
I want to be able to use the OR statements, but I am not sure how to do that with the single or double characters (N, S, E, W, NW, NE, SW, SE).
What am I doing wrong?
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Answer
Do not overuse non-capturing groups, (?:SW) is the same as SW.
Also, you do not want to match SE in SED token, use anchors, ^ and $.
Use
JavaScript
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{"REGEX":"^(?:N|S|E|W|NW|NE|SW|SE)$"}2
See proof.
Case insensitive variant:
JavaScript
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{"REGEX":"(?i)^(?:N|S|E|W|NW|NE|SW|SE)$"}2
Explanation
JavaScript
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--------------------------------------------------------------------------------2
^ the beginning of the string3
--------------------------------------------------------------------------------4
(?: group, but do not capture:5
--------------------------------------------------------------------------------6
N 'N'7
--------------------------------------------------------------------------------8
| OR9
--------------------------------------------------------------------------------10
S 'S'11
--------------------------------------------------------------------------------12
| OR13
--------------------------------------------------------------------------------14
E 'E'15
--------------------------------------------------------------------------------16
| OR17
--------------------------------------------------------------------------------18
W 'W'19
--------------------------------------------------------------------------------20
| OR21
--------------------------------------------------------------------------------22
NW 'NW'23
--------------------------------------------------------------------------------24
| OR25
--------------------------------------------------------------------------------26
NE 'NE'27
--------------------------------------------------------------------------------28
| OR29
--------------------------------------------------------------------------------30
SW 'SW'31
--------------------------------------------------------------------------------32
| OR33
--------------------------------------------------------------------------------34
SE 'SE'35
--------------------------------------------------------------------------------36
) end of grouping37
--------------------------------------------------------------------------------38
$ before an optional n, and the end of the39
string40