Split words in letters

AlvaroS

Hi everyone.
Thanks a lot for reading this post and helping me.

I have a QStringList words which has the next:

QStringList words_of_line

words_of_line = [-10,30]

Now I would like to get just the numbers so -10 and 30.
The format will be always the same, some examples:
[5,6] [10,-5] [-1,20]

So how can I get just the numbers? (it it is negative I have to get the negative.)

mrjj

Hi
You can use the split function

http://doc.qt.io/qt-5/qstring.html#split

kshegunov

@AlvaroS
You can indeed use split as @mrjj said, but you can also extract them directly with a regex (\[\s*(-?[0-9]+)\s*,\s*(-?[0-9]+)\s*\]). However the regex will probably work much better if you had a whole string.

Devopia53

@AlvaroS

Also, you can use the capture method of regular expression.
Something like this:

QRegExp         rx("(-?\\d+),(-?\\d+)");

foreach (auto str, QStringList() << "[5,6]" << "[10,-5]" << "[-1,20]") {
    if (rx.indexIn(str) > -1)
        qDebug() << "lvalue:" << rx.cap(1) << "rvalue:" << rx.cap(2);
}

SGaist

Hi,

To add to my fellow regexp fans. Use QRegularExpression with Qt 5. QRegExp has been deprecated.

AlvaroS

@mrjj Thanks! I have solved with this! it is easy!!

AlvaroS

@SGaist hi! First of all thanks for answering!!
It is a little hard for me. Where can I find the Regular expresion in C++? like -? d+. the meaning of that!

Thanks a lot!

AlvaroS

@Devopia53 said:

@AlvaroS

Also, you can use the capture method of regular expression.
Something like this:

QRegExp         rx("(-?\\d+),(-?\\d+)");

foreach (auto str, QStringList() << "[5,6]" << "[10,-5]" << "[-1,20]") {
    if (rx.indexIn(str) > -1)
        qDebug() << "lvalue:" << rx.cap(1) << "rvalue:" << rx.cap(2);
}

@kshegunov said:

@AlvaroS
You can indeed use split as @mrjj said, but you can also extract them directly with a regex (\[\s*(-?[0-9]+)\s*,\s*(-?[0-9]+)\s*\]). However the regex will probably work much better if you had a whole string.

Thanks for asnwering friends! Like I said in the last post. Where can I find the regular expressions of C++ like -? s*??? The meaning of that!

Thanks!

AlvaroS

hi again.

Now I am trying split one word but I have to get the first paramenter. For example:

i have this: /home/user/image.jpeg

So I have to get just "/home/user/"
So every characters until the last /.

How can I do that?!

Thanks!!

kshegunov

@AlvaroS said:

Where can I find the regular expressions of C++ like -? s*??? The meaning of that!

You can't because this is not part of C++. This is something Qt provides for you through the QRegularExpression class. That class is using PCRE (perl-compatible regular expressions), so you can see the syntax on any site that deals with them. For example:
http://www.pcre.org/pcre.txt
or more humanly presented:
http://php.net/manual/en/reference.pcre.pattern.syntax.php

Also you can experiment and test PCREs here:
https://regex101.com/ (select PCRE flavor in the left sidebar).

Now I am trying split one word but I have to get the first paramenter. For example:
i have this: /home/user/image.jpeg

For this, you're better of using Qt's file/dir/fileinfo classes. For the simplest of examples:

QString filePath = "/home/user/image.jpeg";
QString dirPath = QFileInfo(filePath).dir().path();

SGaist

You'll be also interested by the regular expression tool

AlvaroS

@kshegunov said:

@AlvaroS said:

Where can I find the regular expressions of C++ like -? s*??? The meaning of that!

You can't because this is not part of C++. This is something Qt provides for you through the QRegularExpression class. That class is using PCRE (perl-compatible regular expressions), so you can see the syntax on any site that deals with them. For example:
http://www.pcre.org/pcre.txt
or more humanly presented:
http://php.net/manual/en/reference.pcre.pattern.syntax.php

Also you can experiment and test PCREs here:
https://regex101.com/ (select PCRE flavor in the left sidebar).

Now I am trying split one word but I have to get the first paramenter. For example:
i have this: /home/user/image.jpeg

For this, you're better of using Qt's file/dir/fileinfo classes. For the simplest of examples:
QString filePath = "/home/user/image.jpeg";
QString dirPath = QFileInfo(filePath).dir().path();

@SGaist said:

You'll be also interested by the regular expression tool

Thanks a lot. I have done good what I wanted to do :)
Have a good day.