From: Josh Cheek <josh.cheek@...>
Date: 2013-05-24T13:38:25+09:00
Subject: Re: Regular expression to find a break in a pattern

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On Thu, May 23, 2013 at 11:13 AM, Joel Pearson <lists@ruby-forum.com> wrote:

> I have a large file which lots of gibberish in and I'm trying to find
> the meaningful sections.
>
> Essentially I'll have something like this:
>
> ________________
>
> To: "1313131"
> From: "1313131"
> random data lines
>
> To: "1313132"
> From: "1313132"
> random data lines
>
> To: "1313133"
> From: "1313132"
> random data lines
>
> To: "1313134"
> From: "1313134"
> random data lines
>
> ________________
>
> What I need to do is locate the line(s) where From is different from To.
> In this case, the one From "1313132" To "1313133".
>
> I don't know how to do this kind of match, but I assume that Ruby has a
> way?
>
> --
> Posted via http://www.ruby-forum.com/.
>
>

Here is a regex that works for your example data.

text = '
To: "1313131"
From: "1313131"
random data lines

To: "1313132"
From: "1313132"
random data lines

To: "1313133"
From: "1313132"
random data lines

To: "1313134"
From: "1313134"
random data lines

To: "abc"
From: "def"
random data lines
'

regex = /To: "(.*?)"\nFrom: "(?!\1)(.*?)"$/

text.scan(regex)  # => [["1313133", "1313132"], ["abc", "def"]]

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On Thu, May 23, 2013 at 11:13 AM, Joel Pearson <span dir=3D"ltr">&lt;<a hre=
f=3D"mailto:lists@ruby-forum.com" target=3D"_blank">lists@ruby-forum.com</a=
>&gt;</span> wrote:<br><div class=3D"gmail_quote"><blockquote class=3D"gmai=
l_quote" style=3D"margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left=
:1ex">
I have a large file which lots of gibberish in and I&#39;m trying to find<b=
r>
the meaningful sections.<br>
<br>
Essentially I&#39;ll have something like this:<br>
<br>
________________<br>
<br>
To: &quot;1313131&quot;<br>
From: &quot;1313131&quot;<br>
random data lines<br>
<br>
To: &quot;1313132&quot;<br>
From: &quot;1313132&quot;<br>
random data lines<br>
<br>
To: &quot;1313133&quot;<br>
From: &quot;1313132&quot;<br>
random data lines<br>
<br>
To: &quot;1313134&quot;<br>
From: &quot;1313134&quot;<br>
random data lines<br>
<br>
________________<br>
<br>
What I need to do is locate the line(s) where From is different from To.<br=
>
In this case, the one From &quot;1313132&quot; To &quot;1313133&quot;.<br>
<br>
I don&#39;t know how to do this kind of match, but I assume that Ruby has a=
<br>
way?<br>
<span class=3D"HOEnZb"><font color=3D"#888888"><br>
--<br>
Posted via <a href=3D"http://www.ruby-forum.com/" target=3D"_blank">http://=
www.ruby-forum.com/</a>.<br>
<br>
</font></span></blockquote></div><div><br></div><div><br></div><div>Here is=
 a regex that works for your example data.</div><br><div><div><div><div>tex=
t =3D &#39;</div><div>To: &quot;1313131&quot;</div><div>From: &quot;1313131=
&quot;</div>
<div>random data lines</div><div><br></div><div>To: &quot;1313132&quot;</di=
v><div>From: &quot;1313132&quot;</div><div>random data lines</div><div><br>=
</div><div>To: &quot;1313133&quot;</div><div>From: &quot;1313132&quot;</div=
>
<div>random data lines</div><div><br></div><div>To: &quot;1313134&quot;</di=
v><div>From: &quot;1313134&quot;</div><div>random data lines</div><div><br>=
</div><div>To: &quot;abc&quot;</div><div>From: &quot;def&quot;</div><div>
random data lines</div><div>&#39;</div><div><br></div><div>regex =3D /To: &=
quot;(.*?)&quot;\nFrom: &quot;(?!\1)(.*?)&quot;$/</div><div><br></div><div>=
text.scan(regex) =A0# =3D&gt; [[&quot;1313133&quot;, &quot;1313132&quot;], =
[&quot;abc&quot;, &quot;def&quot;]]</div>
</div></div></div>

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