regex pro

[steve]

here's the deal...cvs, tick encapsulted data. trying to use regex's to
validate records. here's an example row:

'AD,'BF','13246 5','06/09/2004','','BNSF' ,'A','TYPE','12 78','','BR','29 99',''
,'LX','','01',' 09','1','','',' ','','','','',' ','CUSTOM JOB CODE TEST'

record type is in the 8th column ('1278'). using regex b/c there are a
miriad of types that cause other data w/n the record (or related records) to
be in/valid. i'm having problems getting a match on the generalization of
the first 7 columns:

something like this:

(?=(?:(?<!','). *(?!=',')',')){ 7}(?:'1278(?=', '))

(?=(?:(?<!','). *(?!=',')',')){ 7} represents the first 7 colums.

if someone can help me generalize that patter, i'd appreciate it very much.

tia,

steve

[Cor Ligthert]

Hi Terry,

Again exactly the same

I dont discard it. I simply dont like it, everytime I look at a complex
regExp, it reminds me of the old days where people used to cram code in so
tight because of memory constraints that it was unreadable, or of die hard C programmers who like to write code which is impossible to undersrtand.

Thats my point. If you dont agree with me, then thats fine.

With the addition that I sometimes think that it is used as a kind of
obfuscating the code for others.

However the last sentence from you (OHM) is as well for me.

Cor

[Lloyd Sheen]

If you have ever processed lots of text like screen scrapping you will end
up using regex. I agree that it is somewhat hard to see what it does but
once you learn it like everything you will wonder why you did not use it
before. But I had to buy a book since resources on the web are sparse and
MS documentation is pretty much non-existant.

Lloyd Sheen

"Cor Ligthert" <no**********@p lanet.nl> wrote in message
news:uk******** *****@TK2MSFTNG P11.phx.gbl...

Hi Terry,

Again exactly the same

I dont discard it. I simply dont like it, everytime I look at a complex
regExp, it reminds me of the old days where people used to cram code in so tight because of memory constraints that it was unreadable, or of die

hard C

programmers who like to write code which is impossible to undersrtand.

Thats my point. If you dont agree with me, then thats fine.

With the addition that I sometimes think that it is used as a kind of
obfuscating the code for others.

However the last sentence from you (OHM) is as well for me.

Cor

[Cor Ligthert]

Hi Lloyd,

I never say never, however it is not the first choise from me while I not
say forever do not use it.
When you have to do complex text changes in one search through a not
orginized documents I believe there are not much alternatives, however I see
it here often special for simple changes.

Cor

If you have ever processed lots of text like screen scrapping you will end
up using regex. I agree that it is somewhat hard to see what it does but
once you learn it like everything you will wonder why you did not use it
before. But I had to buy a book since resources on the web are sparse and
MS documentation is pretty much non-existant.

[steve]

| With the addition that I sometimes think that it is used as a kind of
| obfuscating the code for others.

set the regex options to ignore white space and then indent and add comments
w/n the regex. what you have in that case is a programming language. regex
is like a sql statement...but for text. consider what it would take to
program the following:

testString:

'abcdefg', 'lkasjdflk', 'kslthhtjkehslj t', '.zx,mv.zmx', 'abcdefg',
'lkasjdflk', 'kslthhtjkehslj t', '.zx,mv.zmx', 'abcdefg', 'lkasjdflk',
'kslthhtjkehslj t', '.zx,mv.zmx', 'abcdefg', 'lkasjdflk', 'kslthhtjkehslj t',
'.zx,mv.zmx'

your job:

find all ticked strings, then replace the ones that repeat with only one
instance.

well, w/ regex, it is as simple as:

dim regex as new regex("('[^']*?', )(?:'[^']*?', )*(\1)")
testString = regex.replace(t estString, "$1")

if the pattern looks complex, ignore whitespace and add your comments and/or
indenting or whatever. pretty simple.

but again, to each their own.

[Cor Ligthert]

Hi Steve,

so, both C and regex are not your friends? ;^)

Although I wrote that there are circumstances that I do not ommit things as
regex forever, I get the idea that you try (without directly saying it
however with that single ;^) to hit the knowledge of OHM and me.

Try this

Dim teststring1 As String =
"'abcdefg','lka sjdflk','kslthh tjkehsljt','.zx ,mv.zmx','abcde fg'," & _
"'lkasjdflk','k slthhtjkehsljt' ,'.zx,mv.zmx',' abcdefg','lkasj dflk'," & _
"'kslthhtjkehsl jt','.zx,mv.zmx ','lkasjdflk',' abcdefg','lkasj dflk','kslthhtj k
ehsljt'," & _
"'.zx,mv.zm x'"
Dim start As Integer = Environment.Tic kCount
Dim teststring2 As String
For i As Integer = 0 To 10000
Dim regex As New
System.Text.Reg ularExpressions .Regex("('[^']*?',)(?:'[^']*?',)*(\1)")
teststring2 = regex.Replace(t eststring1, "$1")
Next
Console.Write(t eststring2 & "time: " & _
(Environment.Ti ckCount - start).ToString & vbCrLf)
start = Environment.Tic kCount
Dim teststring3 As String

For i As Integer = 0 To 10000
Dim sb As System.Text.Str ingBuilder
sb = New System.Text.Str ingBuilder
Dim sp As String() = Split(teststrin g1, "','")
sp(0) = sp(0).Substring (1)
sp(sp.Length - 1) = sp(sp.Length - 1).Substring(0, _
sp(sp.Length - 1).Length - 1)
For Each da1 As String In sp
Dim da2 As String = "'" & da1 & "'"
If sb.ToString.Ind exOf(da2) = -1 Then
sb.Append(da2)
sb.Append(",")
End If
Next
teststring3 = sb.ToString.Sub string(0, sb.ToString.Len gth - 1)
Next
Console.Write(t eststring3 & "time: " & _
(Environment.Ti ckCount - start).ToString & vbCrLf)

You will see that the second one without the regex is 4 times faster and
gives the same result.
About the style and code we can discus if the second as well reach a kind of
obfuscating style, however that is for me the same as with the Regex sample.

Cor

[One Handed Man \( OHM - Terry Burns \)]

'C' was a great language as far as I am concerned, I used it for several
years quite happily, so I would accredit myself with a reasonable
understanding of it.

However, I personally know two programmers who used to write code in way
which was designed to demonstrate ( to the knowledgeable eye ) their
expertise in understanding the nuances of the compiler. I've seen a piece of
code which printf'ed a poem which no obvious source. All of it looked like
garbage, not unlike a RegExp.

--

OHM ( Terry Burns )
. . . One-Handed-Man . . .
"steve" <[e-mail]> wrote in message
news:10******** *****@corp.supe rnews.com...

this just hit me as funny logical consequence...

|die hard C
| programmers who like to write code which is impossible to undersrtand.

punctuated differently:

"die hard C programmers who like to write code, which is impossible to
understand."

the are only two logical assumptions...o nly die hard C programmers like to
write code that is impossible to understand...or ...ockham's razor - any code can be made very hard to understand; few, if any, programmers of any
language "like" to write hard to understand code; understanding is inference from experience; therefore, it is simplest to say that the language of C is impossible for you to understand (since understanding is wholly an
individual endeavor). and, as we all know, this simplest answer or solution is more oft' than not, the correct one.

so, both C and regex are not your friends? ;^)

just playing w/ you ohm.

cheers.

[steve]

i was kidding w/ ohm.

ahhhh...i wonder what the difference w/b if the data itself contained no
identifying marker by which you could perform a nifty split operation? that
would require you to rewrite your entire function...i'd just have to change
the pattern in my example and still be left w/ two lines of code to
maintain. the regex pattern itself is no longer considered obfuscation if,
like i said, one were to place comments w/n it (just as you would w/ any
language).

but i digress...i can see my humor was lost to offense. appologies s/b
applied where they are needed to both you and ohm.

later,

steve
"Cor Ligthert" <no**********@p lanet.nl> wrote in message
news:eW******** ******@TK2MSFTN GP10.phx.gbl...
| Hi Steve,
|
| > so, both C and regex are not your friends? ;^)
|
| Although I wrote that there are circumstances that I do not ommit things
as
| regex forever, I get the idea that you try (without directly saying it
| however with that single ;^) to hit the knowledge of OHM and me.
|
| Try this
|
| Dim teststring1 As String =
| "'abcdefg','lka sjdflk','kslthh tjkehsljt','.zx ,mv.zmx','abcde fg'," & _
| "'lkasjdflk','k slthhtjkehsljt' ,'.zx,mv.zmx',' abcdefg','lkasj dflk'," & _
|
"'kslthhtjkehsl jt','.zx,mv.zmx ','lkasjdflk',' abcdefg','lkasj dflk','kslthhtj k
| ehsljt'," & _
| "'.zx,mv.zm x'"
| Dim start As Integer = Environment.Tic kCount
| Dim teststring2 As String
| For i As Integer = 0 To 10000
| Dim regex As New
| System.Text.Reg ularExpressions .Regex("('[^']*?',)(?:'[^']*?',)*(\1)")
| teststring2 = regex.Replace(t eststring1, "$1")
| Next
| Console.Write(t eststring2 & "time: " & _
| (Environment.Ti ckCount - start).ToString & vbCrLf)
| start = Environment.Tic kCount
| Dim teststring3 As String
|
| For i As Integer = 0 To 10000
| Dim sb As System.Text.Str ingBuilder
| sb = New System.Text.Str ingBuilder
| Dim sp As String() = Split(teststrin g1, "','")
| sp(0) = sp(0).Substring (1)
| sp(sp.Length - 1) = sp(sp.Length - 1).Substring(0, _
| sp(sp.Length - 1).Length - 1)
| For Each da1 As String In sp
| Dim da2 As String = "'" & da1 & "'"
| If sb.ToString.Ind exOf(da2) = -1 Then
| sb.Append(da2)
| sb.Append(",")
| End If
| Next
| teststring3 = sb.ToString.Sub string(0, sb.ToString.Len gth - 1)
| Next
| Console.Write(t eststring3 & "time: " & _
| (Environment.Ti ckCount - start).ToString & vbCrLf)
|
| You will see that the second one without the regex is 4 times faster and
| gives the same result.
| About the style and code we can discus if the second as well reach a kind
of
| obfuscating style, however that is for me the same as with the Regex
sample.
|
| Cor
|
|

[One Handed Man \( OHM - Terry Burns \)]

No appology needed, I was smirking while both reading and replying. RegExp
does have its place as you say.

Cheers

OHM ( Terry Burns )
. . . One-Handed-Man . . .
"steve" <[e-mail]> wrote in message
news:10******** *****@corp.supe rnews.com...

i was kidding w/ ohm.

ahhhh...i wonder what the difference w/b if the data itself contained no
identifying marker by which you could perform a nifty split operation? that would require you to rewrite your entire function...i'd just have to change the pattern in my example and still be left w/ two lines of code to
maintain. the regex pattern itself is no longer considered obfuscation if,
like i said, one were to place comments w/n it (just as you would w/ any
language).

but i digress...i can see my humor was lost to offense. appologies s/b
applied where they are needed to both you and ohm.

later,

steve
"Cor Ligthert" <no**********@p lanet.nl> wrote in message
news:eW******** ******@TK2MSFTN GP10.phx.gbl...
| Hi Steve,
|
| > so, both C and regex are not your friends? ;^)
|
| Although I wrote that there are circumstances that I do not ommit things
as
| regex forever, I get the idea that you try (without directly saying it
| however with that single ;^) to hit the knowledge of OHM and me.
|
| Try this
|
| Dim teststring1 As String =
| "'abcdefg','lka sjdflk','kslthh tjkehsljt','.zx ,mv.zmx','abcde fg'," & _
| "'lkasjdflk','k slthhtjkehsljt' ,'.zx,mv.zmx',' abcdefg','lkasj dflk'," & _
|
"'kslthhtjkehsl jt','.zx,mv.zmx ','lkasjdflk',' abcdefg','lkasj dflk','kslthhtj k | ehsljt'," & _
| "'.zx,mv.zm x'"
| Dim start As Integer = Environment.Tic kCount
| Dim teststring2 As String
| For i As Integer = 0 To 10000
| Dim regex As New
| System.Text.Reg ularExpressions .Regex("('[^']*?',)(?:'[^']*?',)*(\1)")
| teststring2 = regex.Replace(t eststring1, "$1")
| Next
| Console.Write(t eststring2 & "time: " & _
| (Environment.Ti ckCount - start).ToString & vbCrLf)
| start = Environment.Tic kCount
| Dim teststring3 As String
|
| For i As Integer = 0 To 10000
| Dim sb As System.Text.Str ingBuilder
| sb = New System.Text.Str ingBuilder
| Dim sp As String() = Split(teststrin g1, "','")
| sp(0) = sp(0).Substring (1)
| sp(sp.Length - 1) = sp(sp.Length - 1).Substring(0, _
| sp(sp.Length - 1).Length - 1)
| For Each da1 As String In sp
| Dim da2 As String = "'" & da1 & "'"
| If sb.ToString.Ind exOf(da2) = -1 Then
| sb.Append(da2)
| sb.Append(",")
| End If
| Next
| teststring3 = sb.ToString.Sub string(0, sb.ToString.Len gth - 1)
| Next
| Console.Write(t eststring3 & "time: " & _
| (Environment.Ti ckCount - start).ToString & vbCrLf)
|
| You will see that the second one without the regex is 4 times faster and
| gives the same result.
| About the style and code we can discus if the second as well reach a kind of
| obfuscating style, however that is for me the same as with the Regex
sample.
|
| Cor
|
|