Imbuter2000

simple regular expression that doesn't work as expected

5 posts in this topic

#1 ·  Posted (edited)

I'm going mad for a regular expression that works not like expected.

The source with the regular expression is this:

#include <array.au3>
$string = FileRead("with_null.CSV")
;$string = FileRead("without_null.CSV")
Local $array = StringRegExp($string, '(\V*)\v{1,2}', 3)
_ArrayDisplay($array) with_null.CSV

I read that "\v" matches a vertical tab (\u000B) so:
question 1) why and where does it find occurrencies of \v? it seems that \v matches new line characters too (unexpectedly)
question 2) why is the result with "with_null.CSV" trunked (unexpected) while the result with "without_null.CSV" is not trunked (expected)?

with_null.CSV

without_null.CSV

Edited by Imbuter2000

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1) \v "matches any vertical whitespace character" (help file) obviously including newline chars

2) The Null char interrupts a char sequence in a string
So unless you absolutely need to keep the Nulls the best way is to remove them

#include <array.au3>
$string = FileRead("with_null.CSV")
$string = StringRegExpReplace($string, '\x00', "")
Local $array = StringRegExp($string, '\V+', 3)
_ArrayDisplay($array)

 

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#3 ·  Posted (edited)

1) \v "matches any vertical whitespace character" (help file) obviously including newline chars

2) The Null char interrupts a char sequence in a string
So unless you absolutely need to keep the Nulls the best way is to remove them

#include <array.au3>
$string = FileRead("with_null.CSV")
$string = StringRegExpReplace($string, '\x00', "")
Local $array = StringRegExp($string, '\V+', 3)
_ArrayDisplay($array

Ah mikell you are a lifesaver! thank you so much!!!
I didn't read that new part of the AutoIT help page of StringRegExp and I read on this Microsoft page https://msdn.microsoft.com/en-us/library/4edbef7e(v=vs.110).aspx (about .NET Framework) that "\v  Matches a vertical tab, \u000B." that confused me.

Actually what happened is that I used this function that converts CSV to 2D array 
https://www.autoitscript.com/forum/topic/96357-csv-to-2d-array-with-regexp/?do=findComment&comment=692864
This function contains the   "StringRegExp($sCSV & @CR, '(\V*)\v{1,2}', 3)"  and started to truncate the lines when the CSV started to contain the null in the middle of each line.
Unfortunately I don't have the right to modify the CSV.

Is there a way in the regex to cross the null(s)? 

Edited by Imbuter2000

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The regexp engine doesn't have any issue with the NUL character (0x00), but displaying a string containing NULs doesn't work, even if the string itself isn't affected:

Local $s = 'abc' & Chr(0) & 'def'
ConsoleWrite('Length of $s = ' & StringLen($s) & ' --> ' & $s & @LF)
MsgBox(0, '', $s)
Local $t = StringRegExpReplace($s, '\x00', '_')
ConsoleWrite(@LF & $t & @LF)

 


This wonderful site allows debugging and testing regular expressions (many flavors available). An absolute must have in your bookmarks.
Another excellent RegExp tutorial. Don't forget downloading your copy of up-to-date pcretest.exe and pcregrep.exe here
RegExp tutorial: enough to get started
PCRE v8.33 regexp documentation latest available release and currently implemented in AutoIt beta.

SQLitespeed is another feature-rich premier SQLite manager (includes import/export). Well worth a try.
SQLite Expert (freeware Personal Edition or payware Pro version) is a very useful SQLite database manager.
An excellent eBook covering almost every aspect of SQLite3: a must-read for anyone doing serious work.
SQL tutorial (covers "generic" SQL, but most of it applies to SQLite as well)
A work-in-progress SQLite3 tutorial. Don't miss other LxyzTHW pages!
SQLite official website with full documentation (may be newer than the SQLite library that comes standard with AutoIt)

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Unfortunately I don't have the right to modify the CSV.

You don't need to modify the csv file, but if you want a result to be correctly displayed you have to read the file to a string and then remove the nulls or replace them by a space (which is usual) or by an underscore or whatever you want before applying the regex   :)

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