Removing character(s) from the middle of a string

[pm771]

Hi

I'm using BRU 2.7.0.4

Let say we have files names with "-"s in the middle. Something like this:
aaa-bbb
1234--ddd
eee---wwww

We want to remove "-"s using Regular Expressions (and not the Remove (5) )

The following works:

Code: Select all

Match: ([^-]*)(-+)(.*)
Replace: \1\3

But the following does not:

Code: Select all

Match: (.*)(-+)(.*)
Replace: \1\3

Is it the intended behavior or a bug?

TIA, Eugene

[Stefan]

Hi

I'm using BRU 2.7.0.4

Let say we have files names with "-"s in the middle. Something like this:
aaa-bbb
1234--ddd
eee---wwww

We want to remove "-"s using Regular Expressions (and not the Remove (5) )

The following works:

Code: Select all

Match: ([^-]*)(-+)(.*)
Replace: \1\3

But the following does not:

Code: Select all

Match: (.*)(-+)(.*)
Replace: \1\3

Is it the intended behavior or a bug?

TIA, Eugene

Try
RegEx(1)
Match: (.*)(-+)(.*)
Replace: \1#\3

and you see that your regex works greedy.
This means the first "(.+)" eats all till the last dash. That's normal.

Test it
INPUT:
Test-1.txt
Test--2Zwei.txt
Test---3Drei.txt
Test----4Vier.txt
OUTPUT:
Test#1.txt
Test-#2Zwei.txt
Test--#3Drei.txt
Test---#4Vier.txt

You see that the first (.+) match all but the last dash.


So we try this
RegEx(1)
Match: (.*?)(-+)(.*)
Replace: \1\3
or
RegEx(1)
Match: (.*?)-+(.*)
Replace: \1\2

and you will see it works as indented:
OUTPUT:
Test1.txt
Test2Zwei.txt
Test3Drei.txt
Test4Vier.txt

The "?" switch to non-greedy and so the first expression ".*" stop at the first occurrence of the next expression "-+".
You just have to learn how regex work

An other logically regex would be
RegEx(1)
Match: (.*[^-])(-+)(.*)
Replace: \1\3
which means: none-or-more of any sign till an dash

So you has been already on the right track with
Match: ([^-]*)(-+)(.*)
Replace: \1\3


HTH?

[pm771]

Stefan,

Thank you very much for the response.

The "?" switch to non-greedy and so the first expression ".*" stop at the first occurrence of the next expression "-+".
You just have to learn how regex work

I didn't know about greedy / lazy functioning of + operator.

Your explanation and http://www.regular-expressions.info/repeat.html clarified it for me.

Eugene

[Stefan]

Thanks for the feedback.

Now at least i taken the time to read this info you pointed to
and did learn something new: <[^>]+> "An Alternative to Laziness"

I read such things many times but now i hope this time i have got it (Learning by doing is the best one can do)