Hej Folks.
I cannot find an answer for my question, so apologize if that's a duplication.
I have a Qt Application and running a Qt::Process.
Furthermore, I show the stdout and stderr of the process to the user, so errors can be understood.
My approach is to append every output to a QString I can show in a Text QML Type.
QObject::connect(update, &QProcess::readyRead, [update, this] () {
QString newline = QString(update->readAll());
m_updateLog.append(newline);
emit newUpdateLog();
});
The problem is that with a lot of \r (Carriage Return), the QString quickly gets pretty long.
I hoped to somehow reduce the length of the QString to his "readable" length?
Example : QString("Hello\nWorld\rUniverse") becomes QString("Hello\nUniverse")
I tried to write my own logic … but I'm kinda too stupid that it's work properly.
In the future I will cut the QString to a max length, but in cases with a lot of CR it gets kinda ugly,
because important informations will be cut :/.
( Example: QString("Loaded:\n0.4%\r0.5%\r0.6%\r0.7%\r0.8%\r0.9%\r1.0%") )
Thanks for any help.
I wouldn't expect there to be any magic that understands that stuff before a "\r" is effectively erased -- that logic is in the text rendering implementation not any string formatting. You would have to implement it yourself; you would have to track where the "\r" is backing up the cursor to.
I would suggest replacing your single string (whatever type m_updateLog is) with a list or array of strings, with each line of output (delimited by "\r" or "\n") as its own string. That way when you see a "\r" you can drop the last element. Also if the array gets too long, you can remove the first elements to shorten it, so that you have a kind of rolling tail of the output.
Related
I need to split string by comma, that not quoted like:
foo, bar, "hello, user", baz
to get:
foo
bar
hello, user
baz
Using std.csv:
import std.csv;
import std.stdio;
void main()
{
auto str = `foo,bar,"hello, user",baz`;
foreach (row; csvReader(str))
{
writeln(row);
}
}
Application output:
["foo", "bar", "hello, user", "baz"]
Note that I modified your CSV example data. As std.csv wouldn't correctly parse it, because of space () before first quote (").
You can use next snippet to complete this task:
File fileContent;
string fileFullName = `D:\code\test\example.csv`;
fileContent = File (fileFullName, "r");
auto r = regex(`(?!\B"[^"]*),(?![^"]*"\B)`);
foreach(line;fileContent.byLine)
{
auto result = split(line, r);
writeln(result);
}
If you are parsing a specific file format, splitting by line and using regex often isn't correct, though it will work in many cases. I prefer to read it in character by character and keep a few flags for state (or use someone else's function where appropriate that does it for you for this format). D has std.csv: http://dlang.org/phobos/std_csv.html or my old old csv.d which is minimal but basically works too: https://github.com/adamdruppe/arsd/blob/master/csv.d (haha 5 years ago was my last change to it, but hey, it still works)
Similarly, you can kinda sorta "parse" html with regex... sometimes, but it breaks pretty quickly outside of simple cases and you are better off using an actual html parser (which probably is written to read char by char!)
Back to quoted commas, reading csv, for example, has a few rules with quoted content: first, of course, commas can appear inside quotes without going to the next field. Second, newlines can also appear inside quotes without going to the next row! Third, two quote characters in a row is an escaped quote that is in the content, not a closing quote.
foo,bar
"this item has
two lines, a comma, and a "" mark!",this is just bar
I'm not sure how to read that with regex (eyeballing, I'm pretty sure yours gets the escaped quote wrong at least), but it isn't too hard to do when reading one character at a time (my little csv reader is about fifty lines, doing it by hand). Splitting the lines ahead of time also complicates compared to just reading the characters because you might then have to recombine lines later when you find one ends with a closing quote! And then your beautiful byLine loop suddenly isn't so beautiful.
Besides, when looking back later, I find simple character readers and named functions to be more understandable than a regex anyway.
So, your answer is correct for the limited scope you asked about, but might be missing the big picture of other cases in the file format you are actually trying to read.
edit: one last thing I want to pontificate on, these corner cases in CSV are an example of why people often say "don't reinvent the wheel". It isn't that they are really hard to handle - look at my csv.d code, it is short, pretty simple, and works at everything I've thrown at it - but that's the rub, isn't it? "Everything I've thrown at it". To handle a file format, you need to be aware of what the corner cases are so you can handle them, at least if you want it to be generic and take arbitrary user input. Knowing these edge cases tends to come more from real world experience than just taking a quick glance. Once you know them though, writing the code again isn't terribly hard, you know what to test for! But if you don't know it, you can write beautiful code with hundreds of unittests... but miss the real world case your user just happens to try that one time it matters.
So I've outputted a string of various ASCII characters. This program involves parts of this string being modified, and then re-displayed.
Instead of clearing the entire screen and re-displaying everything, which produces an unwanted flicker effect, I've decided on moving the cursor and then rewriting only the characters that have changed.
I'm moving the cursor with SetConsoleCursorPosition, part of windows.h.
However, once I try and cout something, it pushes all of the text in front of it ahead by a space; another unwanted effect.
In an attempt to fix this, I tried various forms of 'cout<<"\b";' to remove the old, unmodified character. But there was either no effect, or it actually added a space, which is obviously not a desired effect here.
I read somewhere that in order to remove the unwanted character that you actually have to use the escape sequence twice, Example: '\b\b', because the first one moves the cursor back a space, and the second one overwrites the character in front of it with a space (' ') or something like that.
'\b\b' didn't work either, unsurprisingly. Or maybe that is surprising, I don't actually know.
My question is: How do I remove the unwanted character? Or better yet, How do I overwrite text that has already been outputted with new text?
EDIT: I apologize, I'm running Windows 7
I think maybe clearing the ENABLE_INSERT_MODE with the SetConsoleMode function might help. It should prevent the console from inserting characters and pushing the old characters forward.
This a question I've solved and wanted to post in Q&A style because I think more people could use the solution. Or maybe improve the solution, show where it breaks.
The problem
You wanna do something with quoted strings and/or comments in a body of text. You wanna extract them, highlight them, what have you. But some quoted strings are inside comments, and sometimes comment-characters are inside strings. And strings delimiters can be escaped, and comments can be line-comments or block comments. And when you thought you had a solution somebody complains that it doesn't work when there's a regex-literal in his JavaScript. What do?
Concrete example
var ret = row.match(/'([^']+)'/i); // Get 1st single quoted string's content
if (!ret) return ''; /* return if there's no matches
Otherwise turn into xml: */
var message = '\t<' + ret[1].replace(/\[1]/g, '').replace(/\/#(\w+)/i, ' $1=""') + '></' + ret[1].match(/[A-Z_]\w*/i)[0] + '>';
alert('xml: \'' + message + '\''); /*
alert("xml: '" + message + "'"); // */
var line = prompt('How do line-comments start? (e.g. //)', '//');
// do something with line
This code is nonsense, but how do I do the right thing in each of the cases of the above JavaScript?
The only thing I found that comes close is this: Comments in string and strings in comments where Jan Goyvaerts himself answered with a similar approach. But that one doesn't handle apostrophe-escaping yet.
I've broken the regex into 4 lines corresponding with the 4 paths in the graph, don't keep those line-breaks in there if you ever use this.
(['"])(?:(?!\1|\\).|\\.)*\1|
\/(?![*/])(?:[^\\/]|\\.)+\/[igm]*|
\/\/[^\n]*(?:\n|$)|
\/\*(?:[^*]|\*(?!\/))*\*\/
Debuggex Demo
This code grabs 4 types of "blocks" that can contain the other 3. You can iterate through this and do with each one whatever you want or discard it because it's not the one you wanna do anything to.
This one is specific for JavaScript as it's a language I'm familiar with. But you could easily adapt this to the language of your preference.
Anyone see a way in which this code breaks?
Edit I have since been notified that the general pattern is described very well here: https://stackoverflow.com/a/23589204/2684660, neato!
I'm asking this question because i dont know how to google it, i dont find the right keywords.
I have a QListWidget with strings inside. The strings are very long and if i disable horizontal scrolling, which is what i want, then the text ends with ... because it is too long.
I would like to have the text to display the end of the text and the beginning like:
This is very long text to This is ... text instead of This is very long ...
Is there any simple way to achieve this without having to manipulate the string? I need the full string afterwards and i dont want to store extra data. Any help is appreciated.
There is indeed a very easy solution: Lock for TextElideMode and Qt::ElideMiddle (setTextElideMode ( Qt::TextElideMode mode )).
This is my string:
"this is my sentence"
I would like to have this output:
"sentence my is this"
I would like to select a few words on a line (in a buffer) and reverse it word by word.
Can anyone help me?
It's not totally clear what the context is here: you could be talking about text in a line in a buffer or about a string stored in a VimScript variable.
note: Different interpretations of the question led to various approaches and solutions.
There are some "old updates" that start about halfway through that have been rendered more or less obsolete by a plugin mentioned just above that section. I've left them in because they may provide useful info for some people.
full line replacement
So to store the text from the current line in the current buffer in a vimscript variable, you do
let words = getline('.')
And then to reverse their order, you just do
let words = join(reverse(split(words)))
If you want to replace the current line with the reversed words, you do
call setline('.', words)
You can do it in one somewhat inscrutable line with
call setline('.', join(reverse(split(getline('.')))))
or even define a command that does that with
command! ReverseLine call setline('.', join(reverse(split(getline('.')))))
partial-line (character-wise) selections
As explained down in the "old updates" section, running general commands on a character- or block-wise visual selection — the former being what the OP wants to do here — can be pretty complicated. Ex commands like :substitute will be run on entire lines even if only part of the line is selected using a character-wise visual select (as initiated with an unshifted v).
I realized after the OP commented below that reversing the words in a partial-line character-wise selection can be accomplished fairly easily with
:s/\%V.*\%V./\=join(reverse(split(submatch(0))))/
wherein
\%V within the RE matches some part of the visual selection. Apparently this does not extend after the last character in the selection: leaving out the final . will exclude the last selected character.
\= at the beginning of the replacement indicates that it is to be evaluated as a vimscript expression, with some differences.
submatch(0) returns the entire match. This works a bit like perl's $&, $1, etc., except that it is only available when evaluating the replacement. I think this means that it can only be used in a :substitute command or in a call to substitute()
So if you want to do a substitution on a single-line selection, this will work quite well. You can even pipe the selection through a system command using ...\=system(submatch(0)).
multiple-line character-wise selections
This seems to also work on a multiple-line character-wise selection, but you have to be careful to delete the range (the '<,'> that vim puts at the beginning of a command when coming from visual mode). You want to run the command on just the line where your visual selection starts. You'll also have to use \_.* instead of .* in order to match across newlines.
block-wise selections
For block-wise selections, I don't think there's a reasonably convenient way to manipulate them. I have written a plugin that can be used to make these sorts of edits less painful, by providing a way to run arbitrary Ex commands on any visual selection as though it were the entire buffer contents.
It is available at https://github.com/intuited/visdo. Currently there's no packaging, and it is not yet available on vim.org, but you can just git clone it and copy the contents (minus the README file) into your vimdir.
If you use vim-addon-manager, just clone visdo in your vim-addons directory and you'll subsequently be able to ActivateAddons visdo. I've put in a request to have it added to the VAM addons repository, so at some point you will be able to dispense with the cloning and just do ActivateAddons visdo.
The plugin adds a :VisDo command that is meant to be prefixed to another command (similarly to the way that :tab or :silent work). Running a command with VisDo prepended will cause that command to run on a buffer containing only the current contents of the visual selection. After the command completes, the buffer's contents are pasted into the original buffer's visual selection, and the temp buffer is deleted.
So to complete the OP's goal with VisDo, you would do (with the words to be reversed selected, and with the above-defined ReverseLine command available):
:'<,'>VisDo ReverseLine
old updates
...previous updates follow ... warning: verbose, somewhat obselete, and mostly unnecessary...
The OP's edit makes it more clear that the goal here is to be able to reverse the words contained in a visual selection, and specifically a character-wise visual selection.
This is decidedly not a simple task. The fact that vim does not make this sort of thing easy really confused me when I first started using it. I guess this is because its roots are still very much in the line-oriented editing functionality of ed and its predecessors and descendants. For example, the substitute command :'<,'>s/.../.../ will always work on entire lines even if you are in character-wise or block-wise (ctrlv) visual selection mode.
Vimscript does make it possible to find the column number of any 'mark', including the beginning of the visual selection ('<) and the end of the visual selection ('>). That is, as far as I can tell, the limit of its support. There is no direct way to get the contents of the visual selection, and there is no way to replace the visual selection with something else. Of course, you can do both of those things using normal-mode commands (y and p), but this clobbers registers and is kind of messy. But then you can save the initial registers and then restore them after the paste...
So basically you have to go to sort of extreme lengths to do with parts of lines what can easily done with entire lines. I suspect that the best way to do this is to write a command that copies the visual selection into a new buffer, runs some other command on it, and then replaces the original buffer's visual selection with the results, deleting the temp buffer. This approach should theoretically work for both character-wise and block-wise selections, as well as for the already-supported linewise selections. However, I haven't done that yet.
This 40-line code chunk declares a command ReverseCharwiseVisualWords which can be called from visual mode. It will only work if the character-wise visual selection is entirely on a single line. It works by getting the entire line containing the visual selection (using getline()) running a parameterized transformation function (ReverseWords) on the selected part of it, and pasting the whole partly-transformed line back. In retrospect, I think it's probably worth going the y/p route for anything more featureful.
" Return 1-based column numbers for the start and end of the visual selection.
function! GetVisualCols()
return [getpos("'<")[2], getpos("'>")[2]]
endfunction
" Convert a 0-based string index to an RE atom using 1-based column index
" :help /\%c
function! ColAtom(index)
return '\%' . string(a:index + 1) . 'c'
endfunction
" Replace the substring of a:str from a:start to a:end (inclusive)
" with a:repl
function! StrReplace(str, start, end, repl)
let regexp = ColAtom(a:start) . '.*' . ColAtom(a:end + 1)
return substitute(a:str, regexp, a:repl, '')
endfunction
" Replace the character-wise visual selection
" with the result of running a:Transform on it.
" Only works if the visual selection is on a single line.
function! TransformCharwiseVisual(Transform)
let [startCol, endCol] = GetVisualCols()
" Column numbers are 1-based; string indexes are 0-based
let [startIndex, endIndex] = [startCol - 1, endCol - 1]
let line = getline("'<")
let visualSelection = line[startIndex : endIndex]
let transformed = a:Transform(visualSelection)
let transformed_line = StrReplace(line, startIndex, endIndex, transformed)
call setline("'<", transformed_line)
endfunction
function! ReverseWords(words)
return join(reverse(split(a:words)))
endfunction
" Use -range to allow range to be passed
" as by default for commands initiated from visual mode,
" then ignore it.
command! -range ReverseCharwiseVisualWords
\ call TransformCharwiseVisual(function('ReverseWords'))
update 2
It turns out that doing things with y and p is a lot simpler, so I thought I'd post that too. Caveat: I didn't test this all too thoroughly, so there may be edge cases.
This function replaces TransformCharwiseVisual (and some of its dependencies) in the previous code block. It should theoretically work for block-wise selections too — it's up to the passed Transform function to do appropriate things with line delimiters.
function! TransformYankPasteVisual(Transform)
let original_unnamed = [getreg('"'), getregtype('"')]
try
" Reactivate and yank the current visual selection.
normal gvy
let #" = a:Transform(#")
normal gvp
finally
call call(function('setreg'), ['"'] + original_unnamed)
endtry
endfunction
So then you can just add a second command declaration
command! -range ReverseVisualWords
\ call TransformYankPasteVisual(function('ReverseWords'))
tangentially related gory detail
Note that the utility of a higher-level function like the ones used here is somewhat limited by the fact that there is no (easy or established) way to declare an inline function or block of code in vimscript. This wouldn't be such a limitation if the language weren't meant to be used interactively. You could write a function which substitutes its string argument into a dictionary function declaration and returns the function. However, dictionary functions cannot be called using the normal invocation syntax and have to be passed to call call(dictfunct, args, {}).
note: A more recent update, given above, obsoletes the above code. See the various sections preceding old updates for a cleaner way to do this.
Maybe:
:s/\v(.*) (.*) (.*) (.*)/\4 \3 \2 \1/
Of course you probably need to be more specific in the first part to find that particular sentence. Generally you can refer to match groups as \number with \0 being the whole match.
Here's a way to do by calling out to Ruby. After selecting the line you want to reverse, you can do this in command mode to replace it:
!ruby -e 'puts ARGF.read.strip.split(/\b/).reverse.join'
I found the solution myself thank to your answers and a lot of trying :)
This works:
function! Test()
exe 'normal ' . 'gv"ay'
let r = join(reverse(split(getreg('a'))))
let #a = r
exe 'normal ' . 'gv"ap'
endfunction
Didn't thought that I was enable to write such a function :)