PureBasic Forums - English

Posted: **Thu Jul 31, 2025 2:39 pm**

Hi

Is this a bug or not.

lcTxt.s=",,,,,,,,"
lcTxt=ReplaceString(lcTxt,",,",",0,")
Debug lcTxt ; result ",0,,0,,0,,0," but expected ",0,0,0,0,0,0,0"

Posted: **Thu Jul 31, 2025 2:51 pm**

I would confirm the behavior....
Sometimes using the full arguments helps, but not here.
Only the while loop can do it.

Code: Select all

lcTxt.s=",,,,,,,,"
lcTxt=ReplaceString(lcTxt,",,",",0,")
Debug lcTxt ; result ",0,,0,,0,,0," but expected ",0,0,0,0,0,0,0"

; == again 
lcTxt.s=",,,,,,,,"
lcTxt=ReplaceString(lcTxt,",,",",0,", #PB_String_CaseSensitive, 1, 20) 
Debug lcTxt ; result ",0,,0,,0,,0," but expected ",0,0,0,0,0,0,0"

; == again 
lcTxt.s=",,,,,,,,"
While FindString(lcTxt, ",,") 
  lcTxt=ReplaceString(lcTxt,",,",",0,") 
Wend   
Debug lcTxt ; result ",0,,0,,0,,0," but expected ",0,0,0,0,0,0,0"

Debug Output:

Code: Select all

,0,,0,,0,,0,
,0,,0,,0,,0,
,0,0,0,0,0,0,0,

Posted: **Thu Jul 31, 2025 2:55 pm**

swhite wrote:Is this a ReplaceString Bug?

No.
'lcTxt' contains ",," 4 times, and each occurence of ",," is replaced with ",0,". So of course the result is ",0,,0,,0,,0,".

Posted: **Thu Jul 31, 2025 2:59 pm**

I do not think it is a bug. The search and replace is started at the beginning of the source and moves character by character. It does not search the replacements after they have each been made.

Posted: **Thu Jul 31, 2025 3:03 pm**

The experts' explanations make sense to me.
So you need the while loop (see above) for your expected result.

BTW: Maybe it's not so good to use the word bug in subject lines. Actually it's an observed behavior, the decision bug or feature will be made by Fred at the end of all days anyway.

Posted: **Thu Jul 31, 2025 3:13 pm**

Axolotl wrote: Thu Jul 31, 2025 3:03 pm BTW: Maybe it's not so good to use the word bug in subject lines. Actually it's an observed behavior, the decision bug or feature will be made by Fred at the end of all days anyway.

He didn't call it a bug, he asked if it was a bug. Seems reasonable to me.

Posted: **Thu Jul 31, 2025 5:49 pm**

Demivec wrote: Thu Jul 31, 2025 2:59 pm It does not search the replacements after they have each been made.

Yep! And I thank heaven for that! Otherwise, that function would be a whole mess, and could even produce an endless loop.

Posted: **Thu Jul 31, 2025 9:56 pm**

You probably want to do it like this (looks right, but do your own tests):

Code: Select all

lcTxt.s=",,,,,,,,"
lcTxt=ReplaceString(lcTxt,",",",0")
Debug lcTxt ; Result: ,0,0,0,0,0,0,0,0

Posted: **Fri Aug 01, 2025 2:55 pm**

Hi

Thanks for all the responses.

I did realize that the solution was to use "while". It is not a problem if this is the expected behavior. However, it just caught me off guard in that I expected the search to continue from the last character replaced. I also cannot use BarryG's solution because the actual string is more like "'test',,345,'No',,," as it is part of an SQL statement so I do not want to replace every comma with ",0". I just gave my example to indicate the behavior and what I had expected.

Simon

Posted: **Sat Aug 02, 2025 8:51 am**

A regular expression can help here:
The expression ",(?=,)|,$" search for a "," which is followed by a other "," (?=,) or the end of the string ($):

Code: Select all

Define String.s = "'test',,345,'No',,," 

Define Regex.i = CreateRegularExpression(#PB_Any, ",(?=,)|,$")

Define NewString.s = ReplaceRegularExpression(Regex, String, ",0")

Debug String
Debug NewString

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