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Date: Mon, 1 Jul 2013 20:27:51 -0600
Subject: Re: Regular expression negative look-ahead
From: Jason Friedman <jsf80238@gmail.com>
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Found this:
http://stackoverflow.com/questions/13871833/negative-lookahead-assertion-not-working-in-python
.

This pattern seems to work:
pattern = re.compile(r"^(?!.*(CTL|DEL|RUN))")

But I am not sure why.


On Mon, Jul 1, 2013 at 5:07 PM, Jason Friedman <jsf80238@gmail.com> wrote:

> I have table names in this form:
> MY_TABLE
> MY_TABLE_CTL
> MY_TABLE_DEL
> MY_TABLE_RUN
> YOUR_TABLE
> YOUR_TABLE_CTL
> YOUR_TABLE_DEL
> YOUR_TABLE_RUN
>
> I am trying to create a regular expression that will return true for only
> these tables:
> MY_TABLE
> YOUR_TABLE
>
> I tried these:
> pattern = re.compile(r"_(?!(CTL|DEL|RUN))")
> pattern = re.compile(r"\w+(?!(CTL|DEL|RUN))")
> pattern = re.compile(r"(?!(CTL|DEL|RUN)$)")
>
> But, both match.
> I do not need to capture anything.
>

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<div dir=3D"ltr">Found this: =C2=A0<a href=3D"http://stackoverflow.com/ques=
tions/13871833/negative-lookahead-assertion-not-working-in-python">http://s=
tackoverflow.com/questions/13871833/negative-lookahead-assertion-not-workin=
g-in-python</a>.<div>
<br></div><div>This pattern seems to work:</div><div><div>pattern =3D re.co=
mpile(r&quot;^(?!.*(CTL|DEL|RUN))&quot;)</div></div><div><br></div><div>But=
 I am not sure why.</div></div><div class=3D"gmail_extra"><br><br><div clas=
s=3D"gmail_quote">
On Mon, Jul 1, 2013 at 5:07 PM, Jason Friedman <span dir=3D"ltr">&lt;<a hre=
f=3D"mailto:jsf80238@gmail.com" target=3D"_blank">jsf80238@gmail.com</a>&gt=
;</span> wrote:<br><blockquote class=3D"gmail_quote" style=3D"margin:0 0 0 =
.8ex;border-left:1px #ccc solid;padding-left:1ex">
<div dir=3D"ltr">I have table names in this form:<div>MY_TABLE</div><div>MY=
_TABLE_CTL</div><div>MY_TABLE_DEL</div><div>MY_TABLE_RUN</div><div>YOUR_TAB=
LE<br></div><div>YOUR_TABLE_CTL<br></div><div>YOUR_TABLE_DEL<br></div><div>

YOUR_TABLE_RUN<br></div><div><br></div><div>I am trying to create a regular=
 expression that will return true for only these tables:</div><div><div>MY_=
TABLE</div><div>YOUR_TABLE<br></div></div><div><br></div><div>I tried these=
:</div>

<div><div>pattern =3D re.compile(r&quot;_(?!(CTL|DEL|RUN))&quot;)</div></di=
v><div><div><div>pattern =3D re.compile(r&quot;\w+(?!(CTL|DEL|RUN))&quot;)<=
br></div></div></div><div><div>pattern =3D re.compile(r&quot;(?!(CTL|DEL|RU=
N)$)&quot;)<br>

</div></div><div><br></div><div>But, both match.</div><div>I do not need to=
 capture anything.</div></div>
</blockquote></div><br></div>

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