C-h h!
It happens quite often to me that I try to C-M-% a text. Thus I use query-replace-regexp interactively. So I enter the search regex and Emacs asks meekly for the replacement text, when in fact my search regex does not match any text!
Ideally, I would like to be signaled as soon as possible that my regex does not match.
Is there a way out of this?
One way to do this is to start with C-M-s, for isearch-forward-regexp, and interactively enter the regexp. That way, you'll see that it reaches the first match, and any further matches will be highlighted. Then, still in isearch mode, type C-M-%. The regexp from the isearch will automatically become the search regexp for the replacement command.
Related
I have an XML code:
<Line1>Matched_text Other_text</Line1>
<Line2>Text_to_replace</Line2>
How to tell Notepad++ to find Matched_text and replace Text_to_replace to Replaced_text? There are several similar blocks of code, with one exactly Matched _text and different Other_text and Text_to_replace. I want to replace all in once.
My idea is to put
Matched_text*<Line2>*</Line2>
in the Find field, and
Matched_text*<Line2>Replaced_text</Line2>
in the Replace field. I know that \1 in regex might be useful, but I don't know where to start.
The actual code is:
<Name>Matched_text, Other_text</Name>
<IsBillable>false</IsBillable>
<Color>-Text_to_replace</Color>
The regex you're looking for is something like the following.
Find: (Matched_text[\w,\s<>\/]*<Color>-).*(</Color>)
Replace: \1Replaced_text\2
Broken down:
`()` is how you tell regex that you want to keep things (for use in /1, /2, etc.), these are called capture groups in regex land.
`Matched_text[\w,\s<>\/]*` means you want your anchor `Matched_text` and everything after it up till the next part of the expression.
`<Color>-).*(</Color>)` Select everything between <Color>- and </Color> for replacement.
If you have any questions about the expression, I highly recommend looking at a regex cheatsheet.
I got a string like this:
PREFIX-('STRING WITH SPACES TO REPLACE')
and i need this:
PREFIX-('STRING_WITH_SPACES_TO_REPLACE')
I'm using Notepad++ for the Regex Search and Replace, but i'm shure every other Editor capable of regex replacements can do it to.
I'm using:
PREFIX-\('(.*)(\s)(.*)'\)
for search and
PREFIX-('\1_\3')
for replace
but that replaces only one space from the string.
The regex search feature in Notepad++ is very, very weak. The only way I can see to do this in NPP is to manually select the part of the text you want to work on, then do a standard find/replace with the In selection box checked.
Alternatively, you can run the document through an external script, or you can get a better editor. EditPad Pro has the best regex support I've ever seen in an editor. It's not free, but it's worth paying for. In EPP all I had to do was this:
search: ((?:PREFIX-\('|\G)[^\s']+)\s+
replace: $1_
EDIT: \G matches the position where the previous match ended, or the beginning of the input if there was no previous match. In other words, the first time you apply the regex, \G acts like \A. You can prevent that by adding a negative lookahead, like so:
((?:PREFIX-\('|(?!\A)\G)[^\s']+)\s+
If you want to prevent a match at the very beginning of the text no matter what it starts with, you can move the lookahead outside the group:
(?!\A)((?:PREFIX-\('|\G)[^\s']+)\s+
And, just in case you were wondering, a lookbehind will work just as well as a lookahead:
((?:PREFIX-\('|(?<!\A)\G)[^\s']+)\s+
You have to keep matching from the beggining of the string untill you can match no more.
find /(PREFIX-\('[^\s']*)\s([^']*'\))/
replace $1_$2
like: while (/(PREFIX-\('[^\s']*)\s([^']*'\))/$1_$2/) {}
How about using Replace all for about 20 times? Or until you're sure no string contains more spaces
Due to nature of regex, it's not possible to do this in one step by normal regular expression.
But if I be in your place, I do such replaces in several steps:
find such patterns and mark them with special character
(Like replacing STRING WITH SPACES TO REPLACE with #STRING WITH SPACES TO REPLACE#
Replace #([^#\s]*)\s to #\1_ server times.
Remove markers!
I studied a little the regex tool in Notepad++ because I didn't know their possibilities.
I conclude that they aren't powerful enough to do what you want.
Your are obliged to learn and use a programming language having a real regex capability. There are a number of them. Personnaly, I use Python. It would take 1 mn to do what you want with it
You'd have to run the replace several times for each space but this regex will work
/(?<=PREFIX-\(')([^\s]+)\s+/g
Replace with
\1_ or $1_
See it working at http://refiddle.com/10z
How can I delete some text that match with a regex in emacs?
I suppose that using:
'(query-replace-regexp PATTERN EMPTY)
and:
'(replace-regexp PATTERN EMPTY)
but they throw:
perform-replace: Invalid regexp: "Premature end of regular expression".
In general, you can delete text that matches a given regexp by using the empty string "" as the replacement in the two functions you mention. However, as others mentioned in the comments above, your regular expression is faulty.
For instance, if your buffer contains the following text:
1. My todo list
1.1. Brush teeth
1.2. Floss
2. My favorite movies
2.1. Star Wars episodes 4-6
and you would like to get rid of the numbers at the beginning of each line, you could place the cursor at the beginning of the buffer and then type M-C-% (that is, you press at a time: ALT, CTRL, Shift, 5) to invoke the command query-replace-regexp. You'll get asked two parameters in the minibuffer, first the regexp to match than the replacement string.
So, in our example, you could use the following regexp:
\([0-9]\.\)+\s-
as the first parameter, and simply hit ENTER for the second parameter, i.e., don't specify anything as the replacement. That way, the replacement is the empty string: you replace what ever matches the regexp with nothing.
query-replace-regexp will ask you interactively for every match if you want to replace it or if you want to skip it. This is the "query"-part in query-replace-regexp and it is helpful to see if the regexp you came up with actually matches what you thought it does. If you're sure it does, you can type ! to make Emacs replace the remaining matches without asking every time.
If you use M-x replace-regexp instead of M-C-% Emacs will replace every match without asking for input at every match.
For the special case that you'd like to delete whole lines when a certain part of the line matches a regexp, there's also delete-matching-lines and its evil, goatee-wearing twin brother from a parallel universe delete-non-matching-lines.
How do you do a query-replace-regexp in Emacs that will match across multiple lines?
as a trivial example I'd want <p>\(.*?\)</p> to match
<p>foo
bar
</p>
M-x re-builder
is your friend. And it led me to this regular expression:
"<p>\\(.\\|\n\\)*</p>"
which is the string version of
<p>\(.\|^J\)*</p> ;# where you enter ^J by C-q C-j
And that works for me when I do re-search-forward, but not when I do 'query-replace-regexp. Unsure why...
Now, when doing a 're-search-forward (aka C-u C-s), you can type M-% which will prompt you for a replacement (as of Emacs 22). So, you can use that to do your search and replace with the above regexp.
Note, the above regexp will match until the last </p> found in the buffer, which is probably not what you want, so use re-builder to build a regexp that comes closer to what you want. Obviously regular expressions can't count parenthesis, so you're on your own for that - depends on how robust a solution you want.
Try character classes. As long as you're using only ASCII character set, you can use [[:ascii:]] instead of the dot. Using the longer [[:ascii:][:nonascii:]] ought to work for everything.
I know the regex for doing a global replace,
%s/old/new/g
How do you go about doing an interactive search-replace in Vim?
Add the flag c (in the vim command prompt):
:%s/old/new/gc
will give you a yes/no prompt at each occurrence of 'old'.
Vim's built-in help offers useful info on the options available once substitution with confirmation has been selected. Use:
:h :s
Then scroll to section on confirm options. Screenshot below:
For instance, to substitute this and all remaining matches, use a.
Mark Biek pointed out using:
%s/old/new/gc
for a global search replace with confirmation for each substitution. But, I also enjoy interactively verifying that the old text will match correctly. I first do a search with a regex, then I reuse that pattern:
/old.pattern.to.match
%s//replacement/gc
The s// will use the last search pattern.
I think you're looking for c, eg s/abc/123/gc, this will cause VIM to confirm the replacements. See :help :substitute for more information.
I usually use the find/substitute/next/repeat command :-)
/old<CR>3snew<ESC>n.n.n.n.n.n.n.
That's find "old", substitute 3 characters for "new", find next, repeat substitute, and so on.
It's a pain for massive substitutions but it lets you selectively ignore some occurrences of old (by just pressing n again to find the next one instead of . to repeat a substitution).
If you just want to count the number of occurrences of 'abc' then you can do %s/abc//gn. This doesn't replace anything but just reports the number of occurrences of 'abc'.
If your replacement text needs to change for each matched occurrence (i.e. not simply choosing Yes/No to apply a singular replacement) you can use a Vim plugin I made called interactive-replace.
Neovim now has a feature inccommand which allows you to preview the substitution:
inccommand has two options:
set inccommand=split previews substitutions in a split pane
set inccommand=nosplit previews substitution in the active buffer
Image taken from: https://medium.com/#eric.burel/stop-using-open-source-5cb19baca44d
Documentation of the feature: https://neovim.io/doc/user/options.html#'inccommand'