QStringList remove spaces from strings

Question

What a best way for trimming all strings in string list? I try to use replaceInStrings:

QStringList somelist;
// ... //
// add some strings
// ... //
somelist.replaceInStrings(QRegExp("^\s*"),"");

but spaces not removed.

Answer 1

QRegExp("^\s*")

\ is special symbol, so you must use \\ when you need to insert slash into string

QRegExp("^\\s*")

Answer 2

As another answer already told, you need to escape the backslash. You also want to change the expression to match one or more spaces and not 0 or more spaces, try using: QRegExp("^\\s+")

Answer 3

If you can use C++11 (qt5 qmake project file: CONFIG += c++11), then try this short snippet:

QStringList somelist;
// fill list
for(auto& str : somelist)
    str = str.trimmed();

It will run through the list with a reference and the trimmed function call result will be assigned back to the item in the original list.

Without the use of C++11 you can use Qt methods with Java-Style, mutable iterators:

QMutableListIterator<QString> it(somelist);
while (it.hasNext()) {
    it.next();
    it.value() = it.value().trimmed();
}

The latter method is just perfect, if you, for instance, want to remove empty strings after they have been trimmed:

QMutableListIterator<QString> it(somelist);
while (it.hasNext()) {
    it.next();
    it.value() = it.value().trimmed();
    if (it.value().length() == 0)
        it.remove(); 

}

The remove is valid, see the Qt java-style iterator docs