regex - search and replace - "remember"?
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I don’t know where in the document mentions where you can take what ever it has been found, and copies text and is pasted in the “replace with”. For example:
abcd/1234/efgh ijkl/5678/mnopbecomes:
abcd/efgh/1234 ijkl/mnop/5678(it’s swapped, by being replaced with [abcd/<memory 2>/<memory 1>]).
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Open the Replace dialog by pressing Ctrl+h and then set up the following search parameters:
Find what box:
(?-s)(.{4})/(.{4})$
Replace with box:\2/\1
Search mode radiobutton: Regular expression
Wrap around checkbox: ticked
. matches newline checkbox: doesn’t matter (because the(?-s)leading off the Find what box contains ansvariant)Then press the Replace All button
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Hmm … question is quite similar to this one, strange.
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@Alan-Kilborn So, it’s something to do with a backreference. Is this caused by the parenthesis? Because the
.means to match any character and{ℕ}is the number of characters. Also, do backreferences’s numbering:-Starts at 0?
-Is numbered from left to right (example, the first parenthesis group is numbered 0 and the last is numbered 2)? -
@Adam-Yik said in regex - search and replace - "remember"?:
Is this caused by the parenthesis?
Yes.
do backreferences’s numbering: Starts at 0?
No, they start at 1, and they aren’t called backreferences, they’re called “capture groups”.
A pseudo-group #0 is for the overall match and is accessed at replace time as
$0rather than\0.Is numbered from left to right
Yes.
he first parenthesis group is numbered 0 and the last is numbered 2)?
No, but close. The first is numbered 1 and the second/last is 2.
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@Alan-Kilborn thanks! sadly, up to 9 can be remembered within parent group at a time. But I think you can get around this by doing this multiple times.
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@Alan-Kilborn To fully understand the subgroup, it is very similar to Directory-based system such as windows 10. However, up to 9 files and folders can exist in a directory, and to refer them on a path, you place each digit and without the path separator
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@Adam-Yik said in regex - search and replace - "remember"?:
thanks! sadly, up to 9 can be remembered within parent group at a time
Actually, there is no such limitation. The substitutions section of the official docs says,
$ℕ,${ℕ},\ℕ⇒ Returns what matched the ℕth subexpression, where ℕ is a positive integer (1 or larger).By using the
${ℕ}notation, you can reference any capture group, not just the first 9. So the fifteenth group would be${15}in the replacement expression. -
@Adam-Yik said in regex - search and replace - "remember"?:
it is very similar to Directory-based system such as windows 10. However, up to 9 files and folders can exist in a directory, and
There is no such limitation in Windows, and it doesn’t have anything to do with regular expression processing. Please don’t spread misinformation.
