CODEWITHSUNDEEP
regexnotepad++replace
kingrichard2005
kingrichard2005

Reputation: 7269

Notepad++ RegeEx group capture syntax

I have a list of label names in a text file I'd like to manipulate using Find and Replace in Notepad++, they are listed as follows:

MyLabel_01
MyLabel_02
MyLabel_03
MyLabel_04
MyLabel_05
MyLabel_06

I want to rename them in Notepad++ to the following:

Label_A_One
Label_A_Two
Label_A_Three
Label_B_One
Label_B_Two
Label_B_Three

The Regex I'm using in the Notepad++'s replace dialog to capture the label name is the following:

((MyLabel_0)((1)|(2)|(3)|(4)|(5)|(6)))

I want to replace each capture group as follows:

\1 = Label_
\2 = A_One
\3 = A_Two
\4 = A_Three
\5 = B_One
\6 = B_Two
\7 = B_Three

My problem is that Notepad++ doesn't register the syntax of the regex above. When I hit Count in the Replace Dialog, it returns with 0 occurrences. Not sure what's misesing in the syntax. And yes I made sure the Regular Expression radio button is selected. Help is appreciated.

UPDATE:

Tried escaping the parenthesis, still didn't work:

\(\(MyLabel_0\)\((1\)|\(2\)|\(3\)|\(4\)|\(5\)|\(6\)\)\)

Upvotes: 4

Views: 6369

Answers (4)

AdrianHHH
AdrianHHH

Reputation: 14038

A regular expression search and replace for

MyLabel_((01)|(02)|(03)|(04)|(05)|(06))

with

Label_(?2A_One)(?3A_Two)(?4A_Three)(?5B_One)(?6B_Two)(?7B_Three)

works on Notepad 6.3.2

The outermost pair of brackets is for grouping, they limit the scope of the first alternation; not sure whether they could be omitted but including them makes the scope clear. The pattern searches for a fixed string followed by one of the two-digit pairs. (The leading zero could be factored out and placed in the fixed string.) Each digit pair is wrapped in round brackets so it is captured.

In the replacement expression, the clause (?4A_Three) says that if capture group 4 matched something then insert the text A_Three, otherwise insert nothing. Similarly for the other clauses. As the 6 alternatives are mutually exclusive only one will match. Thus only one of the (?...) clauses will have matched and so only one will insert text.

Upvotes: 0

Will
Will

Reputation: 102

The easiest way to do this that I would recommend is to use AWK. If you're on Windows, look for the mingw32 precompiled binaries out there for free download (it'll be called gawk).

BEGIN {
    FS = "_0";
    a[1]="A_One";
    a[2]="A_Two";
    a[3]="A_Three";
    a[4]="B_One";
    a[5]="B_Two";
    a[6]="B_Three";
}

{
    printf("Label_%s\n", a[$2]);
}

Execute on Windows as follows:

C:\Users\Mydir>gawk -f test.awk awk.in
Label_A_One
Label_A_Two
Label_A_Three
Label_B_One
Label_B_Two
Label_B_Three

Upvotes: -2

Ed Staub
Ed Staub

Reputation: 15690

Bar bar bar - Notepad++ thinks you're a barbarian.

(obsolete - see update below.) No vertical bars in Notepad++ regex - sorry. I forget every few months, too!

Use [123456] instead.

Update: Sorry, I didn't read carefully enough; on top of the barhopping problem, @Ahmad's spot-on - you can't do a mapping replacement like that.

Update: Version 6 of Notepad++ changed the regular expression engine to a Perl-compatible one, which supports "|". AFAICT, if you have a version 5., auto-update won't update to 6. - you have to explicitly download it.

Upvotes: 4

Ahmad Mageed
Ahmad Mageed

Reputation: 96477

Ed's response has shown a working pattern since alternation isn't supported in Notepad++, however the rest of your problem can't be handled by regex alone. What you're trying to do isn't possible with a regex find/replace approach. Your desired result involves logical conditions which can't be expressed in regex. All you can do with the replace method is re-arrange items and refer to the captured items, but you can't tell it to use "A" for values 1-3, and "B" for 4-6. Furthermore, you can't assign placeholders like that. They are really capture groups that you are backreferencing.

To reach the results you've shown you would need to write a small program that would allow you to check the captured values and perform the appropriate replacements.

EDIT: here's an example of how to achieve this in C#

var numToWordMap = new Dictionary<int, string>();
numToWordMap[1] = "A_One";
numToWordMap[2] = "A_Two";
numToWordMap[3] = "A_Three";
numToWordMap[4] = "B_One";
numToWordMap[5] = "B_Two";
numToWordMap[6] = "B_Three";

string pattern = @"\bMyLabel_(\d+)\b";
string filePath = @"C:\temp.txt";
string[] contents = File.ReadAllLines(filePath);

for (int i = 0; i < contents.Length; i++)
{
    contents[i] = Regex.Replace(contents[i], pattern,
        m =>
        {
            int num = int.Parse(m.Groups[1].Value);
            if (numToWordMap.ContainsKey(num))
            {
                return "Label_" + numToWordMap[num];
            }
            // key not found, use original value
            return m.Value;
        });
}

File.WriteAllLines(filePath, contents);

You should be able to use this easily. Perhaps you can download LINQPad or Visual C# Express to do so.

If your files are too large this might be an inefficient approach, in which case you could use a StreamReader and StreamWriter to read from the original file and write it to another, respectively.

Also be aware that my sample code writes back to the original file. For testing purposes you can change that path to another file so it isn't overwritten.

Upvotes: 5

Related Questions