([SOLVED] regexp question)? - idiot ocurred 0 or 1 times

[kylomas]

Good Morning,

Given the following

1 12 123 9 98 987 11

*- there is a space at the beginning and end of the string

(\d{1,2})

and

(\d\d?)

return the same result. Are these stmts functionally equivalent or is this a coincidence the pattern I am using?

If they are functionally equivalent, when is one preferred over another?

Also,

The first "12" is not reported a a match. Is this because the space before it is "consumed" by the previous match?

Thanks,

kylomas

Note - I am reading through the tutorials cited by various members, including jchd, however, there are as many unanswered questions as answered questions!

Edited October 26, 2012 by kylomas

[Melba23]

kylomas,

Disclaimer: My opinion only and I am far from expert in SREs!

Are these stmts functionally equivalent

Yes.

Is this because the space before it is "consumed" by the previous match?

It might be. What are you using as a pattern and what exactly are you trying to pull from this string? All the 1/2 digit numbers? All 1/2 digit combinations preceded by a space? All 1/2 digit combinations preceded and followed by a space?

M23

[Robjong]

Hi,

yes these are equal.

"(d{1,2})"

d - matches any didgit
{1,2} - tells the engine to match the previous part ( d ) one or two times.

"(dd?)"

d - matches any didgit
d - matches any didgit
? - tells the engine to match the previous part ( the second d ) zero or one times.

So they both allow for one or two digits, and there are a whole lot of other ways to reach the same outcome.

Edit: You might also want to check out the example I gave here:

Edited October 26, 2012 by Robjong

[guinness]

Isn't the first one more optimal?

[Robjong]

Not really, they should result in the same logic in the engine, but to read the expression one might prefer the former.

The matches can be one or two digits. Once the engine encounters a digit the backtrack position is stored.

The engine then goes on to see if it can match a second digit right after the first match, stores the result if it is and continues from there.

If not the engine backtracks to the last known position and saves the result and continues from there.

Edit: added explanation.

Edited October 26, 2012 by Robjong

[jdelaney]

Both will return values that you probably do not expect...such as when you have 3 digits, it will be broken up into a 2digit integer and a 1digit integer.

You need to consider string begin and string ends, or include all following digits: (d+)

[Robjong]

Both will return values that you probably do not expect...such as when you have 3 digits, it will be broken up into a 2digit integer and a 1digit integer.

You need to consider string begin and string ends, or include all following digits: (d+)

Excatly, but this might not be relevant to the OP. Btw. This is excatly what the example I linked to shows.

[Melba23]

jdelaney,

You need to consider string begin and string ends

I quite agree with you, which is why I asked the OP what he actually expects as a return.

M23

[jdelaney]

whoops, misquoted...boundaries are key:

#include <Array.au3>
$a = StringRegExp ( "1 12 123 9 98 987 11", "b(d{1,2})b", 3 )
_ArrayDisplay ( $a )

Edited October 26, 2012 by jdelaney

[kylomas]

@all - Thanks for the responses.

My first question is answered.

My second question cannot be answered because I fucked up. The pattern should have read

( d{1,2} )

. The pattern, entered correctly, is returning "12" and "9". Is that because of this from Robjong

The matches can be one or two digits. Once the engine encounters a digit the backtrack position is stored.

The engine then goes on to see if it can match a second digit right after the first match, stores the result if it is and continues from there.

If not the engine backtracks to the last known position and saves the result and continues from there.

???????

Again, thanks for the prompt replies and apologies for the screw up...

kylomas

[jdelaney]

help us out...what EXACTLY are you expected to return from

1 12 123 9 98 987 11

put it like:

1) #

2) ##

3) etc

[kylomas]

jdelaney,

I am trying to get my arms around this cryptic language. I believe that Robjong answered this question

The first "12" is not reported a a match. Is this because the space before it is "consumed" by the previous match?

or, am I missing something again!

Apologies, again,for posting the regexp incorrectly, and, thank you for your time!

kylomas

[Melba23]

kylomas,

Please post what you want as a return from the RegEx as both jdelaney and I asked above - until then we cannot really answer your question!

M23

[kylomas]

M23,

Apologies if I am not being clear enough. My questions were about syntax and behavior of regexp and have been answered.

Thank you all for your time.

kylomas

P.S. If I seem to be generally confused, it is because I am! I blame too many regexp tutorials in the last 48 hours for this!

[Melba23]

kylomas,

If you are happy that your questions have been answered, then fine....

M23

[jmosley708]

I have a regexp search that works everywhere but in autoit3 it goes like this:

$sd = "Sent by Team:SYSADMIN User:jm5751"

$r = StringRegExp($sd, '([a-z]{2}d{3})(d|[a-z])',01)

ConsoleWrite('user id: ' & $r[0] & @crlf)

I can get the jm575 but I can't get the 1 after or the alpha if there is one. What can I do to fix this?

Thanks

[Malkey]

If the pattern in the second capture group matches text in the test string, that text will be in the second element of the returned array.

$sd = "Sent by Team:SYSADMIN User:jm5751"
$r = StringRegExp($sd, '([a-z]{2}d{3})([da-z]?)', 1)
ConsoleWrite('user id: ' & $r[0] & $r[1] & @CRLF)

@jmosley

You should have started another thread (your own thread) instead of appending to this thread.

[jmosley708]

Thanks, that worked. How do I start a new thread?

[caleb41610]

Thanks, that worked. How do I start a new thread?

edit: never mind, I'm up too late..

Edited October 28, 2012 by caleb41610

[Malkey]

....

@jmosley

You should have started another thread (your own thread) instead of appending to this thread.

..... How do I start a new thread?

When you are logged on to these forums, there is a button made visible near the top of each forum that says "Start New Topic". This will allow you to weave your own topic within the fabric of that chosen forum.