I'm really bad in regular expressions, so please help me.
I need to find in string any pieces like #text.
text mustn't contain any space characters (\\s). It's length must be at least 2 characters ({2,}), and it must contain at least 1 letter(QChar::isLetter()).
Examples:
#c, #1, #123456, #123 456, #123_456 are incorrect#cc, #text, #text123, #123text are correctI use QRegExp.
QRegExp rx("#(\\S+[A-Za-z]\\S*|\\S*[A-Za-z]\\S+)$");
bool result = (rx.indexIn(str) == 0);
rx either finds a non-whitespace followed by a letter and by an unspecified number of non-whitespace characters, or a letter followed by at least non-whitespace.
The shortest I could come up with (which should work, but I haven't tested extensively) is:
QRegExp("^#(?=[0-9]*[A-Za-z])[A-Za-z0-9]{2,}$");
Which matches:
^ the start of the string# a literal hash character(?= then look ahead (but don't match)
[0-9]* zero or more latin numbers[A-Za-z] a single upper- or lower-case latin letter)[A-Za-z0-9]{2,} then match at least two characters which may be upper- or lower-case latin letters or latin numbers$ then find and consume the end of the lineTechnically speaking though this is still wrong. It only matches latin letters and numbers. Replacing a few bits gives you:
QRegExp("^#(?=\\d*[^\\d\\s])\\w{2,}$");
This should work for non-latin letters and numbers but this is totally untested. Have a quick read of the QRegExp class reference for an explanation of each escaped group.
And then to match within larger strings of text (again, untested):
QRegExp("\b#(?=\\d*[^\\d\\s])\\w{2,}\b");
A useful tool is the Regular Expressions Example which comes with the SDK.
Styne666 gave the right regex.
Here is a little Perl script which is trying to match its first argument with this regex:
#!/usr/bin/env perl
use strict;
use warnings;
my $arg = shift;
if ($arg =~ m/(#(?=\d*[a-zA-Z])[a-zA-Z\d]{2,})/) {
print "$1 MATCHES THE PATTERN!\n";
} else {
print "NO MATCH\n";
}
Perl is always great to quickly test your regular expressions.
Now, your question is a bit different. You want to find all the substrings in your text string, and you want to do it in C++/Qt. Here is what I could come up with in couple of minutes:
#include <QtCore/QCoreApplication>
#include <QRegExp>
#include <iostream>
using namespace std;
int main(int argc, char *argv[])
{
QString str = argv[1];
QRegExp rx("[\\s]?(\\#(?=\\d*[a-zA-Z])[a-zA-Z\\d]{2,})\\b");
int pos = 0;
while ((pos = rx.indexIn(str, pos)) != -1)
{
QString token = rx.cap(1);
cout << token.toStdString().c_str() << endl;
pos += rx.matchedLength();
}
return 0;
}
To make my test I feed it an input like this (making a long string just one command line argument):
peter@ubuntu01$ qt-regexp "#hjhj 4324 fdsafdsa #33e #22"
And it matches only two words: #hjhj and #33e.
Hope it helps.
use this regular expression. hope fully your problem will solve with given RE.
^([#(a-zA-Z)]+[(a-zA-Z0-9)]+)*(#[0-9]+[(a-zA-Z)]+[(a-zA-Z0-9)]*)*$
