How can I use the captured group in the same regex

Question

mFoo = foo;
mBar = bar;
// convert to
this.foo = foo;
this.bar = bar;

How to use a regex to handle this substitution? Please help. Here is the method I used in Android Studio (IntelliJ IDEA) Edit -> Find -> Replace in Path

Text to find: m([A-Z])([A-Za-z0-9]+) = L$1$2
Replace with: this\.L$1$2 = L$1$2

Update

L above is a typo. It should be \L according to JetBrains' document

What language/tool? What have you tried? BTW, you can use back-reference. — Tushar, Jan 24 '16 at 06:55
I am using Android Studio (IntelliJ IDEA) `Edit -> Find -> Replace in Path` — bitdancer, Jan 24 '16 at 06:57
You might wanna check if the flavor you are using supports `\1` or `$1` for back referencing. — , Jan 24 '16 at 07:01
[**Find:** `m(\S+)` **Replace:** `this.m$1`](https://regex101.com/r/cL7eL2/2) — Tushar, Jan 24 '16 at 07:03
@noob Unfortunately, it seemed not working with the back referencing in the same regex, or maybe I use it in a wrong way. — bitdancer, Jan 24 '16 at 07:04

score 25 · Accepted Answer · edited Jul 02 '19 at 01:01

25

You can use a pattern with back-reference and grouping the last words after "=":

Text to find:

m([A-Z])([A-Za-z0-9]+) = (L\1\2)

Replace with:

this.L$1$2 = $3

After your comments, I understand that you have also problems with lowercase/uppercase characters. So try this pattern (I have also simplified the regex):

m(\p{Alpha})(\w+) = (((?i)\1)\2)

and this replace string:

this\.L$1$2 = $3

So with your example with an input text:

mContext = context

you obtain this:

this.LContext = context

I don't know if "L" specified in your text/replace string is your typo error or other but if it's so you can change the "replace string" in the following way:

this\.$3 = $3

So you can obtain this:

this.context = context

Let me know if this help you!

edited Jul 02 '19 at 01:01

Keale

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answered Jan 24 '16 at 07:06

Simona R.

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I'll try the backreference feature on Android Studio and it works – Simona R. Jan 24 '16 at 07:12
`L\1` seemed not same as `L$1`, but back-reference `\1` worked. `L\1` cannot match lower case `\1` – bitdancer Jan 24 '16 at 07:16
Could you put a text example? So I'll check the mistake – Simona R. Jan 24 '16 at 07:22
`mContext = context;` I have checked case sensitive option. – bitdancer Jan 24 '16 at 07:23
Ok you have a problem with a lower case not with back-reference. I enriched the answer – Simona R. Jan 24 '16 at 08:02
`L` is a typo. It should be `\L` according to [jetbrains document](https://www.jetbrains.com/idea/help/finding-and-replacing-text-in-file.html) `m(\p{Alpha})(\w+) = (((?i)\1)\2)` and `this\.$3 = $3` works. Thanks a lot. – bitdancer Jan 24 '16 at 12:33
I tried to use `\L` in **Replace with** text field of IntelliJ IDEA's **Replace in Path** dialog, but it shows some kind of syntax error. I don't know what's going on. – bitdancer Jan 24 '16 at 12:46

score 2 · Answer 2 · answered Oct 21 '20 at 06:57

Thanks to Simona R., a simple example in Android Studio.

I want to replace

parentFragmentManager.let { dialogFragment.show(it, AlertDialogFragment.TAG) }

to

dialogFragment.show(parentFragmentManager, AlertDialogFragment.TAG)

in several classes so that two parameters may change.

Then I use replacement with $1 and $2:

parentFragmentManager.let \{ (\w+).show\(it, (\w+).TAG\) \}
$1.show\(parentFragmentManager, $2.TAG\)

score 0 · Answer 3 · answered Jun 20 '19 at 15:37

Say you have a text file with a list of statements:

This is text one$
This is text two!
Is this text three?

And you want to escape all metacharacter. 1. In Android studio open the "Find and Replace" feature by hitting ctrl+R 2. In the "find" field enter: ([[\\^\$.\|\?*+(){}]) 3. Check the checkbox for "Regex" 4. In the "replace" field enter: \$1

The result should now look like this:

This is text one\$
This is text two\!
Is this text three\?

How can I use the captured group in the same regex

3 Answers3

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