Negative lookbehind - fail if you have just passed over [python]
Regular Expressions - Extra Elements example from a Well House Consultants training course
More on Regular Expressions - Extra Elements [link]
Source code: lookbehind.py Module: Q803
# word ensing "ing?on" but NOT is ss just before the "ing?on"
samevalues = re.compile (r'(\w+)(?<!ss)ing.on')
# Very odd extra example - don't allow leading space either!
# gives "rp" and "unt", then "Lav" and "unt"
# samevalues = re.compile (r'(?<!\s)(\w+)(?<!ss)ing.on')
info = ["Hello Orpington, Blessington, Huntingdon", \
"Lavington, Blessington, Huntingdon"]
for demo in info:
result = samevalues.findall(demo)
print demo, "YES"
print demo, "NO"
Hello Orpington, Blessington, Huntingdon YES
Lavington, Blessington, Huntingdon YES
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This example comes from our "Regular Expressions - Extra Elements" training module. You'll find a description of the topic and some other closely related examples on the "Regular Expressions - Extra Elements" module index page.
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